METHOD AND SYSTEM FOR DETERMINING A MINIMUM-PUSH SYNCHRONOUS DESCENTING PROFILE AND DESCENT PROFILE

专利摘要:
A method for determining a descent and minimum thrust descent profile of a target point by an aircraft comprises a first step (4) of calculating an energy differential of the aircraft in the air? between a first initial state of the aircraft at an initial geodesic point Qi and a second final state of the aircraft at the final target point of arrival Qf. The method comprises a second step (6), subsequent to the first step (4), of adjusting an adjustable model profile altitude hm (t) and air velocity Vam (t) of the aircraft to the using parameters such that the modeled adjusted air altitude h (t) and air speed Va (t) profile of the aircraft ensures the consumption of the energy variation of the aircraft in the air Within a required time, the target is set and a required altitude variation is set within the required time period, the aircraft operating continuously in a constant and minimum thrust engine speed. The method comprises a third step (8), subsequent to the second step (6), of determining a lateral geodesic trajectory of the aircraft from the adjusted altitude profile h (t), of the speed profile in the aircraft. Adjusted air Va (t) and knowledge of the wind speeds in the intended geography of the aircraft.
公开号:FR3057986A1
申请号:FR1601522
申请日:2016-10-20
公开日:2018-04-27
发明作者:Benoit DACRE-WRIGHT；Jerome Sacle；Cedric D'Silva
申请人:Thales SA；
IPC主号:

专利说明:

© Publication number: 3,057,986 (to be used only for reproduction orders) © National registration number: 16,01522 ® FRENCH REPUBLIC
NATIONAL INSTITUTE OF INDUSTRIAL PROPERTY
COURBEVOIE © Int Cl ⁸ : G 08 G 5/00 (2017.01), G 01 C 21/20, G 05 D 1/00
A1 PATENT APPLICATION
Date of filing: 20.10.16. (© Applicant (s): THALES— FR. © Priority : © Date of public availability of the request: 04.27.18 Bulletin 18/17. @ Inventor (s): DACRE-WRIGHT BENOIT, SACLE JEROME and D'SILVA CEDRIC. (56) List of documents cited in the preliminary search report: See the end of this brochure © References to other related national documents: ®) Holder (s): THALES. o Extension request (s): © Agent (s): MARKS & CLERK FRANCE General partnership.
FR 3 057 986 - A1
State aircraft initiation (Qi, hi, Vi, ti)
Firtafe constraint (Qtftf, Vi, b)
TT METHOD AND SYSTEM FOR DETERMINING A SYNCHRONOUS DESCENT PROFILE AND MINIMUM DRIVE FOR AN AIRCRAFT.
_ A method of determining a descent profile geography area of expected crossing of the aircraft, and joining in minimum thrust of a target point by an aircraft comprises a first step (4) of calculating a said- energy differential of the aircraft in the air E _g between a first initial state of the aircraft at an initial geodesic point Qi and a second final state of the aircraft at the final arrival target point Qf .
The method comprises a second step (6), consecutive to the first step (4), consisting in adjusting an adjustable model profile of altitude h _m (t) and speed in the air Va _m (t) of the aircraft using parameters so that the adjusted model profile of altitude h (t) and air speed Va (t) of the aircraft ensures the consumption of the energy variation of the aircraft in l 'air E _has within a required period' Leqjjis ^{fixed and a} required altitude variation t _f -1, fixed within the required time, the aircraft operating continuously in an engine speed with constant and minimum thrust.
The method comprises a third step (8), consecutive to the second step (6), of determining a lateral geodesic trajectory of the aircraft from the adjusted altitude profile h (t), the speed profile in l adjusted air Va (t) and knowledge of wind speeds in the
METHOD AND SYSTEM FOR DETERMINING A SYNCHRONOUS DESCENT AND JOINT PROFILE AT MINIMUM PUSH FOR AN AIRCRAFT
The present invention relates to a method for determining a descent profile and joining in minimum thrust of a target point constrained in time by an aircraft, and the system for implementing said method.
The field of application of the method according to the invention is in particular that of planning and guiding the trajectory of an aircraft during the descent phases, as well as the management of air traffic in end-of-route procedures. or approaching airports. The method of the invention can also be applied to the mission management of unmanned aircraft, if the latter are subject to time of flight constraints or insertion into traffic with other aircraft.
In current air traffic control practices, air traffic controllers assign aircraft speeds, or have them maneuver sideways, to ensure efficient sequencing of aircraft in terminal control areas. To help the controller in this task, various tools have been developed. The flight predictions of the aircraft make it possible to estimate its flight time and its arrival time at certain characteristic points of the approach. Tools such as an AMAN arrival manager (in English "Arrivai MANager") can then display the arrival sequence of the various aircraft, and identify for each a time to lose (in English "Time To Loose ”) Or to be won (in English“ Time To Gain ”) to establish a sequencing of aircraft at the runway that meets the required rate, while maintaining the separation necessary for flight safety. The choice of speed setpoint or lateral maneuver is assessed by the controller according to the time to be gained or lost, taking into account the surrounding traffic. The vertical prediction information of the aircraft, available by the ADS-C protocol (in English Automatic Dependent Surveillance Broadcast) in the form of EPP (in English Extended Projected Profile), is not taken into account today in determining the lateral or speed setpoints.
Current aircraft are able to determine an optimized descent profile according to an economic criterion, often a cost index, achieving a compromise between fuel consumption and flight time, sometimes synthesized in the form of a performance criterion. The descent speed profile, as well as the descent start point, are determined so as to maximize the use of a minimum thrust during the descent, while meeting the altitude and speed constraints required by the plan. flight. These constraints can come from the procedures defined in the navigation database and inserted into the flight plan, or have been entered by the pilot, at the request or not of the ground operator.
When an arrival time constraint is required (also called RTA (in English "Required Time of Arrivai") or CTA / CTO (in English "Constrained Time of Arrivai / Overfly"), the on-board flight management system FMS (in English "Flight Management System") can calculate a new speed profile, and the associated descent profile, allowing to satisfy the time constraint. RTA speed calculation profiles can be ensured in several ways, either by searching for a cost index satisfying the constraint as described in patent application US8744768, either according to more elaborate speed strategies, for example using the time profiles corresponding respectively to a flight at minimum, maximum, or economic speed, as described in the patent application US8332145 It is also possible to automatically calculate a lateral maneuver ensuring the desired arrival time as described in the d patent application US8457872. The criterion for determining these maneuvers remains the time constraint, without taking energy management into account.
As part of synchronization operations between ASAS (Airborne Separation Assistance System) or FIM (Flight deck based Interval Management) aircraft, using data exchanged between aircraft by ADS-B protocol, Lateral and speed maneuvers were developed to acquire and then maintain a temporal or spatial spacing behind another aircraft. A lateral maneuver consists in determining, on the current route or along the current heading, a turning point towards a specified point, making it possible to acquire the required spacing as described in applications US8386158, US8078341 or US8862373. Then a speed adjustment is applied to refine and maintain the specified spacing. But the turning point, like the speed setpoint, is established to obtain the required spacing, without taking into account the impact on energy or the descent capacity of the aircraft.
Furthermore, methods have been defined for automatically ensuring the lateral and vertical joining of a flight plan and a reference descent profile as described in patent application US8515598, possibly by maximizing the use of the minimum thrust. as described in application US9188978. During these lateral and vertical capture maneuvers, the energy of the aircraft can be taken into account to adjust the vertical profile, and the distance required to ensure stabilization can be evaluated. In particular, the trajectory can be modified and lengthened to ensure sufficient length to stabilize the aircraft before landing. However, these methods do not take into account a possible time constraint in order to achieve the best compromise between speed and length of trajectory, so as to promote maintenance of descent in minimum thrust.
Taking into account a time constraint in the calculation of an energy optimized descent profile was also proposed in patent application US9026275 but acts on the parameters of altitude, speed, thrust on a lateral trajectory predetermined, without using the lateral modification of the trajectory as a degree of freedom of optimization.
Finally, US patent application 20160063867, published on March 3, 2016, describes an adjustment of the speed and the lateral trajectory, in the presence of a time constraint fixed on a target point of rejoining. The method described consists in monitoring the energy and the time of passage at a point downstream from the descent, so as to ensure compliance with the flight plan. The energy recovery system, described by this document, implements a calculation method which identifies the necessary adjustments to trajectory control parameters to force the aircraft to follow energy recovery and time profiles at target arrival point using a minimum lengthening of the lateral trajectory. The described method can lead to adjustments in speed and lateral trajectory but also includes the possibility of additional thrust or drag. The objective claimed in this document is to secure, as a priority, respect for energy and, if possible, respect for the required flight time, without economic optimization being systematically sought. Furthermore, the method neither describes the methods for calculating the vertical profile, nor the manner in which the effects of the wind and / or of the lateral trajectory on this profile are taken into account. This process therefore does not specify how, in the presence of a significant change in the expected arrival time in the flight time, a lateral maneuver can be devised to respect the new arrival time by achieving the most economically efficient compromise in fuel consumption terms.
A first technical problem is to provide a method of determining a descent profile and joining in minimum thrust of a target point by an aircraft in which the fuel consumption along the profile is minimized without additional energy from the aircraft and respecting the arrival time constraint set at the target descent and rejoin point.
A second technical problem is to provide a method for determining a descent profile and joining in minimum thrust, solution of the first technical problem and simple to implement.
To this end, the subject of the invention is a method for determining a descent profile and joining in minimum thrust of a target point by an aircraft, the descent profile permanently in minimum thrust being defined from a first initial state of the initial aircraft up to a second final state of the time-constrained aircraft, the first initial state of the aircraft comprising a first geodetic starting position Qi, an initial time ti, a first initial altitude hi , a first initial speed of the aircraft VÏ relative to the ground and a first wind speed Wî, the second final state of the aircraft comprising a second geodesic position Qf of arrival at the target point, a final time tf of constraint, a second final altitude hf, a second final speed of the aircraft ~ Vf relative to the ground and a second wind speed Wf, said method being characterized in that it comprises:
a first step of calculating an energy differential of the aircraft in the air ΔΕ _α between the first initial state of the aircraft and the second final state of the aircraft; and a second step, consecutive to the first step consisting in. * providing an adjustable model profile of altitude h _m (t) and of speed in air Va _m (t) of the aircraft, corresponding to a descent strategy in the air which permanently ensures an engine speed at minimum thrust and using one or more adjustable parameters, then to .- adjust the adjustable parameter (s) so that an adjusted profile of altitude h (t) and speed in the air going (t) from the aircraft consumes the energy variation of the aircraft in the air AE _a within the required time Lt _required , and the required altitude variation h, - h _f in the time required with a constant and minimum thrust engine speed at all times; and .- a third step, consecutive to the second step, of determining a lateral geodesic trajectory P (t) of the aircraft from the adjusted altitude profile h (t), of the speed profile in the air adjusted Va (t) and knowledge of the wind speeds in the planned geography area of the aircraft crossing.
According to particular embodiments, the method of determining descent and rejoining in minimum thrust of a target point by an aircraft comprises one or more of the following characteristics;
.- the first step consists in determining the differential of the energy of the aircraft in the air ΔΕ _α as the difference E _ai -E _af between the energy of the aircraft in the air in the initial state E _ai and the energy of the aircraft in the air in the final state E _af , the energy of the aircraft in the air E _ai in the initial state being equal to the sum E _T i + E _W i the total energy E-π of the aircraft in the initial state and a first corrective term E _Wi of the effect of the winds in the initial state on the air slope followed by the aircraft, and the energy of the aircraft in air E _af in the final state being equal to the sum Etî + E _W f of the total energy E _T f of the aircraft in the final state and a second corrective term E _Wf of the effect of winds in the final state on the air slope followed by the aircraft, with ¹
Etî = + m (ti) .g.hi and
E _wi = and
E _T f = + m (t _f ) .gh _f and
Æjyy = - Wy - (Vf - Wf). Wf and m (t /) designating the mass of the aircraft respectively at the initial instant f and the final instant t _f ;
the adjustable model profile of altitude h _m (t) and speed in the air Va _m (t) of the aircraft is broken down into a temporal succession of a number N, greater than or equal to 2, of adjustable elementary profiles altitude h _m (k, t) and speed in the air Va _m (k, t) of the aircraft, the index k being an index identifying the order of temporal succession of the adjustable elementary profiles h _m (k, t), Va _m (k, t) between 1 and N; and the elementary profile h _m (1, t) and Va _m (1, t) evolves over a first elementary time interval IT (1) comprised between the initial time ti and a first intermediate time t (2) respectively forming the associated times the first initial state and a first intermediate state of the aircraft; and for k varying between 2 and N-1, the elementary profile h _m (k, t) and Va _m (k, t) evolves over a k-th elementary time interval IT (k) between one (kl) -th intermediate time t (k) and a k-th intermediate time t (k + 1) respectively forming the times associated with the (kl) -th intermediate state and the k-th intermediate state of the aircraft; and the elementary profile h _m (N, t) and Va _m (N, t) evolve over an N-th elementary time interval IT (N) comprised between the (Nl) -th intermediate time t (N) and the final time tf respectively forming the times associated with the (Nl) th intermediate state and the second final state of the aircraft; and two consecutive intervals IT (k), IT (k + 1) for k varying from 1 to N-1 are contiguous, the adjustable profiles h _m (k, t) and Va _m (k, t), for k varying from 1 to N correspond to phases Φ (Ε) of descent in constant and minimum engine speed, the phases of descent in constant and minimum engine speed being included in the assembly formed by the descent phases at constant CAS speed, the phases in constant acceleration and deceleration phases with constant ER energy ratio;
for each descent phase 4> (k) and the corresponding adjustable profile h _m (k, t) and Va _m (k, t), k varying from 1 to N, the start time of the interval IT (k ), t (k), the end time of the interval IT (k), t (k + 1), the altitudes h _m (t (k)), and h _m (t (k + 1)) , the speeds of the aircraft in the air Va _m (k, t (k)) and Va _m ((k, t (k + 1)), the residual energies SEP _m (k, t (k)), SEP _m (k, t (k + 1)), corresponding respectively to the two instants t (k) and t (k + 1) are connected by the relation:
SEP _m (k, t (kf) + SEP _m (k, t (k + 1). (T (/ c + 1) - t (fc))
Vam ² (k, t (k + lj) - Vam ² (k, t (kf) = [hm (t (k + 1) - h _m (t (k)] + + for k varying from 1 to N,. * when the adjustable profiles h _m (k, t) and Va _m (k, t) correspond to a <t> (k) phase of descent in bounded constant acceleration and in constant and minimum engine speed, the duration At _m (k ) of the k-th elementary interval
IT (t) and the variation in altitude Ah _m (k) over said interval IT (k) verify the equations:
At _m (k) = v _am (k, t (k + i)) - v _am (k, t (k)) and _ ^ gPm (fcT (fc)) + S £ P _m (fc, t (fc + l)) _ VaTn (t (fc)) + Va n (t (fc + l)) ^ + 1)) _
VarntJkJ). * When the adjustable profiles h _m (k, t) and Va _m (k, t) correspond to a phase Φ (1 <) of descent at constant CAS or Mach speed and in constant and minimum engine speed, the duration ât _m (k) of the k-th elementary interval IT (t) and the altitude variation Ah _m (k) over said interval IT (k) verify the equations
Ah _m (k) = h _m (k, t (k + 1)) - h _m (k, t (k)) and
At _m (k) = / Vam ² (t (k + 1) - Vam ² (t (k) y
SEP _m (k, t (k)) + SEP _m (k, t (k + 1)) '+ y _g . * When the adjustable profiles h (k, t) and Va (k, t) correspond to a phase <J> (k) descent during deceleration at constant ER energy ratio and at constant and minimum engine speed, the duration At (k) of the k-th elementary interval IT (t) and the altitude variation Ah (k ) on said interval IT (k) verify the equations:
At _m (k) / Vam ² (t (k + 1) - Vam ² (t (k)) ”ER. (SEP _m (k, t (k)) + SEP _m (k, t (k + 1) )) ' 2g and _{f λ} (1 - ER) (yam ² (t (k + 1)) - Vam ² (t (/ c))) ^{àhmm =} ER 2 ^ the parametric model of altitude profile h ( t) and the speed in the air goes (t) of the aircraft to be adjusted comprises three successive phases: a first phase of acceleration / deceleration towards a desired CAS speed, then a second phase at the constant desired CAS speed, then a third acceleration / deceleration phase towards the final speed, the desired CAS speed and the durations of the three phases being adjusted so as to satisfy the total duration constraint Lt _{required as} well as the altitude variation constraint duration hi ~ h _f the modeled profile of altitude h (t) and speed in air Va (t) of the aircraft to be adjusted comprises three successive phases: a first phase at initial CAS speed on a first tranche of altitude Δ / ι (1) with an adjustable duration allows ant to vary an instant of start of deceleration, then a second phase of deceleration from the initial CAS speed to the final CAS speed, then a third phase of descent at the final CAS speed to the final altitude, the variation d altitude ΔΖι (1) before deceleration is adjusted iteratively to obtain the duration of the first phase;
.- the third step includes a first sub-step during which horizontal starting and ending positions, P _a i and P _a f, within the air mass are determined from horizontal geodesic positions of departure and arrival, Pi and Pf, and of the horizontal wind speed W _ftor (/ i) assuming that the wind speed and direction depend only on the altitude h and using the relation:
ti
P _ai Paf = Pflf ~ W _hor (h (t)) dt and a second sub-step of determining a required lateral distance in the air to be traveled D _a from the speed profile of the aircraft in the air Va (t) and the slope air y (t) using the equation:
ti a third sub-step of determining a lateral trajectory in the air Pa (t) joining the horizontal positions of departure and arrival, Pai and Paf and taking into account the vectors of initial and final speed in the air , the length of the lateral trajectory in the air Pa (t) being constrained by being set equal to the lateral distance in the air required to travel D _a , a fourth sub-step of calculation of a geodetic lateral trajectory Pa ( t) deduced from lateral trajectory in air Pa (t) and from the wind map;
.- the third stage comprises a first sub-stage of supplying a preliminary lateral trajectory of a predetermined type adjustable by the modification of a parameter, and a wind model depending on the altitude and possibly on the horizontal position and possibly time, and a second sub-step of adjusting the at least one parameter of the preliminary lateral trajectory during which the at least one adjustment parameter is modified so that the horizontal geodesic distance traveled along of the preliminary lateral trajectory adjusted taking into account the winds ends precisely at the final geodesic position P _f , and a third sub-step of determining a required horizontal geodesic distance from the altitude profiles h (t) and speed of the aircraft in the air Va (t), by evaluating at each time t the module | κ _ρΛθΓ | the horizontal geodetic speed of the aircraft from the air speed Va (t) and components of the wind speed (XW (t), TW (t)), and by integrating over time the module of the horizontal geodetic speed according to the equations:
d = f | iûf | dt = f Üç -xw t) + nr (t)) dt
Jtl Jtl
XW (t) and TW (t) designating respectively the transverse component and the longitudinal component of the wind at time t;
the method for determining a descent profile and joining the minimum thrust of a target point by an aircraft described above further comprises a fourth step, consecutive to the third step, of correcting the altitude profiles h ( t) and of the speed of the aircraft in the air Va (t), and of the lateral geodesic trajectory, determined respectively in the second and third stages, which take into account a first effect sft) of the wind gradients in the calculation of the residual energy in SEP air and / or a second effect e ₂ (t) of the turns on the load factor which modifies the apparent mass in the calculation of the variation of the residual energy in SEP air (t), the general expression of the residual energy in the air SEP (t) written in the form:
nn, .. Vâm fdVâm _t , dh (f) ^{ίΕΡω =} ~ ~ άΓ ^{+ εΜ} -5r ( ^{1 +} ^ w) where g denotes the acceleration of gravity near the surface of the Earth;
the fourth step is an iterative process, comprising first, second, third, fourth substeps executed in a loop; and the first sub-step, executed initially at the end of the third step and after the fourth sub-step when at least one iteration has been decided during the third sub-step, consists in conventionally determining an evolution time of an aircraft state vector including at least the altitude h (t), the speed of the aircraft in the air Va (t), the geodesic distance traveled D (t) along the current geodesic trajectory P (t), initially determined at the start of a first iteration in the third step or determined during the fourth substep of the fourth step, taking into account the wind gradients and the load factor of the turns in the calculation of the variation of residual energy SEP (t) until either the final position or the final altitude is reached at a stopping point of the current geodetic trajectory; and the second sub-step, executed after the first sub-step, consists of the fact that gross differences ÔD ₁ , dq, ôh, ÔV _a , concerning the geodesic distance traveled, time, altitude, speed in the air are evaluated between the state of the aircraft, considered at the stopping point and calculated taking into account the correction effects, and the desired final state, and in that refined deviations ÔD ₂ , ôt ₂ , concerning distance geodesic traveled, the time are evaluated as a function of the gross differences ÔD- ^, ôt _± , between the state of the aircraft, considered at the stopping point and calculated taking into account the effects of correction, and the final state wish ; and the third substep for testing and deciding to execute an iteration of the loop, executed after the second substep, consists in that the refined deviations δΰ ₂ , ot ₂ of geodesic distance traveled and time d ' arriving at the stopping point are compared with a threshold for stopping the output of the loop ε, a connection is made to the fourth substep is made when at least one of the refined deviations ÔD ₂ , ôt ₂ is greater than or equal at the stopping threshold, and a stopping of the fourth step when the two refined deviations SD ₂ , ot ₂ are strictly below the threshold, the fourth step is completed; and the fourth sub-step, executed when at least one of the refined deviations ÔD ₂ , ôt ₂ is greater than or equal to the stopping threshold, consists in that the current profile of altitude h (t) and of speed in l air Va (t) is readjusted taking into account the refined time difference and reusing the profile adjustment process of the second step, then the lateral trajectory maneuver is readjusted taking into account the distance difference refined and reusing the method of adjusting the lateral trajectory of the third step to obtain an updated current geodetic trajectory;
the refined differences ÔD ₂ , St ₂ of geodesic distance traveled and time of arrival at the stopping point are functions of the gross differences 5D _r , ôt _± , between the state of the aircraft, considered at the stopping point and calculated taking into account the correction effects, and the desired final state, according to the relationships:
St, = St, + -2 —— and
ÔD ₂ = ÔD ₁ + -. Ôt ₂ .V _f
Vf and SEPf respectively designating the final speed and the variation of residual energy at the stop point P (t /);
.- the aircraft is included in all of the planes piloted on board manually or in automatic mode and drones piloted remotely manually or in automatic mode.
The invention also relates to a system for determining a descent profile and joining in minimum thrust of a target point by an aircraft, the descent profile permanently in minimum thrust being defined from a first state. initial of the initial aircraft up to a second final state of the aircraft temporally constrained by a final arrival time tf or a required time delay And _required , the first initial state of the aircraft comprising a first geodetic position Qi of departure, an initial time ti, a first initial altitude hi, a first initial speed of the aircraft Vi relative to the ground and a first wind speed Wi, the second final state of the aircraft comprising a second geodetic position Qf of arrival at the target point, a final constraint time tf, a second final altitude ht, a second final speed of the aircraft ~ Vf relative to the ground and a second wind speed Wf, said dice system termination comprising an aircraft performance database, a means of supplying meteorological data for the environment in which the aircraft operates, a ground station providing the required final time or a required time delay to the aircraft, and one or more electronic computers for calculating the descent and rejoin profile in minimum thrust of a target point, said determination system being configured for:
in a first step, calculate an energy differential of the aircraft in the air ΔΕ _α between the first initial state of the aircraft and the second final state of the aircraft, then in a second step, provide a modeled profile adjustable altitude h _m (t) and speed in the air V _am (t) of the aircraft corresponding to a strategy of speed in the air with a permanent minimum engine thrust, then adjust parameters of said modeled profile adjustable so that the adjusted model profile obtained from altitude h (t) and air speed Va (t) of the aircraft ensures the consumption of the energy variation of the aircraft in air ΔΕ ₃ within the required time & t _required , and the required altitude change hi - h _f within the required time with a minimum engine thrust at all times; then in a third step, determine a geodetic trajectory of the aircraft and a lateral geodetic trajectory from a type of lateral maneuver, from the adjusted altitude profile h (t), from the adjusted air speed profile going (t) and knowledge of the wind speeds in the expected geography area of the aircraft crossing.
According to particular embodiments, the system for determining the descent and joining the minimum thrust of a target point comprises one or more of the following characteristics:
.- the at least one electronic calculator for determining a calculation of a descent profile and rejoining in minimum thrust is an electronic calculator integrated in a flight management system FMS, or an EFB or any aid calculator on-board navigation but not integrated into aircraft avionics, or a computer integrated into an air traffic control ground station, for decision support for a controller, or a computer integrated into a ground mission management station 'a drone ;
.- according to a first configuration, the aircraft comprises a first computer, configured to calculate on board a required intermediate CAS descent speed and a required flight distance, and first transmission means to send these two requirement parameters, and the air traffic control station comprises second transmission means for receiving the required intermediate CAS descent speed and the required flight distance and sending instructions to the aircraft for defining a lateral trajectory and speed, said instructions being determined by a second ground station computer to provide the required flight distance and intermediate speed, or according to a second configuration, the ground station is configured to send the aircraft, in addition to the required delay, a point of convergence along the plane of flight, and the first computer of the aircraft is configured to determine the intermedia speed ire CAS and the required geodetic distance, and identify a turning point, either along a current heading maintenance by a course alignment, or along the current flight plan, by shortening of the trajectory, followed by a flight direct to the point of convergence.
The invention will be better understood on reading the description of several embodiments which will follow, given solely by way of example and made with reference to the drawings in which:
.- Figure 1 is a flowchart of a method according to the invention for determining a descent profile and joining in minimum thrust of a target point by an aircraft;
.- Figure 2 is a detailed flow chart of the first step of the method according to the invention of Figure 1 during which the energy differential of the aircraft in air is calculated between the first initial starting state and the second final state of arrival at the target point;
.- Figure 3 is a detailed flow chart of the second step of the method according to the invention of Figure 1 during which the parameters of a modeled profile of altitude and speed in the air of the aircraft are adjusted , corresponding to a speed strategy in the air of the aircraft permanently at minimum engine thrust;
.- Figure 4 is a view of an example of a modeled profile of altitude and speed in the air of the aircraft, corresponding to a strategy of speed in the air of the aircraft continuously in thrust minimum motor, usable in the second step of Figure 3 and comprising three elementary phases with an intermediate phase at calibrated air speed CAS (in English "Calibrated Air Speed") of constant intermediate descent;
.- Figure 5 is a detailed flowchart of a first embodiment of the third step of the method according to the invention of Figure 1, in which a lateral maneuver is determined before deducing the geodesic trajectory therefrom;
Figure 6 is an illustration of a lateral trajectory in air and of a derived lateral geodetic trajectory, determined using the first embodiment of the third step of Figure 5;
FIG. 7 is a detailed flowchart of a second embodiment of the third step of the method according to the invention of FIG. 1, in which an adjustment of an initial geodesic trajectory, corresponding to a joining strategy, is implemented artwork ;
Figure 8 is an illustration of a first example of an adjusted lateral geodetic trajectory and the lateral trajectory of the aircraft in the corresponding air;
Figure 9 is an illustration of a second example of an adjusted lateral geodesic trajectory and the corresponding lateral trajectory in air;
Figure 10 is a view of an initial lateral geodesic trajectory corresponding to a first joining strategy in which the capture of the final axis is adjusted in distance with a specified distance margin;
Figure 11 is a view of the horizontal component of the initial geodesic path corresponding to a second joining strategy in which the capture of the final axis is adjusted in distance with a specified capture angle;
Figure 12 is a view of an initial lateral geodesic trajectory corresponding to a second joining strategy in which the capture of the final axis is adjusted in distance by modification of the heading;
Figure 13 is a detailed flowchart of the third step of the method according to the invention of Figure 1 during which corrections are applied to the altitude profile and the speed of the aircraft in the air, and to the lateral geodesic trajectory to take into account the effects of wind gradients and turns;
Figure 14 is a view of an architecture of a system according to the invention implementing the method according to the invention of Figure 1.
The method according to the invention consists, during the descent of the aircraft, of determining the descent speed Va (t) and the horizontal or lateral distance D making it possible to reach a descent point and to reach a target point arrival with a specified time or arrival time.
The time constraint or time delay required is typically determined by a ground operator, who transmits this constraint to the aircraft crew. In special mission cases, the time constraint can be determined on board, without the need for a ground-to-board connection.
Likewise, the method can typically be implemented on board, but it is possible to envisage carrying out these treatments on the ground, either for the air traffic controller or for the ground operator of an unmanned vehicle.
In principle, the method according to the invention consists in evaluating or calculating at each current instant the specific residual energy SEP (in English Specifies Excess Power) making it possible to ensure the desired energy reduction within a required time, between the current altitude and speed of the aircraft, and the required altitude and speed at a reference or target point, specified along the descent profile according to the organization of approach procedures and traffic management. According to English terminology, it may for example be a reference point of type "Initial Approach Fix", a reference point of type "Final Approach Fix", or a reference point of type " Metering Fix ”determined on the flight plan. This calculation can take into account the specific residual energy values SEP at the current altitude, at the target altitude at destination, as well as the variations in SEP between the current speed and a desired descent speed, then between the speed of Desired descent and the required speed at the target arrival or reference point. This calculation makes it possible to identify a profile of desired speed of descent into the air Vat) and of desired altitude h (t) making it possible to consume the energy difference within the required time. It is then possible to deduce therefrom first a flight distance relative to the air mass, then by integrating the wind component a ground or geodesic distance, which make it possible to ensure the reduction of energy required in the time required while remaining in minimum engine thrust.
The speed profile in air Va (t) and altitude h (t) desired, as well as the desired lateral geodetic flight distance constitute information which allow to fully determine a lateral maneuver and a speed profile in the air meeting the descent and time constraint requirements, set either by air traffic control or on board the aircraft. It should be noted that the desired lateral geodetic flight distance data, and / or speed setpoint (s) characteristic of the speed profile in the desired air, can also be used in communications between ground and edge to allow a air traffic control operation in accordance with the operational need and the economic efficiency of the flight. These exchanges can be envisaged by data link, or by voice radio, and can be processed automatically on board or entered manually on board the aircraft to adjust the trajectory of the aircraft accordingly.
According to FIG. 1, a method 2 of determining a descent profile and joining in minimum thrust of a target point by an aircraft, comprises at least first, second, third steps 4, 6, 8, executed successively, and optionally comprises a fourth step 10, executed after the third step 8.
The descent profile of the aircraft, permanently at minimum engine thrust, is defined from a first initial state of the aircraft to a second final state of the time-constrained aircraft.
The first initial state of the aircraft comprises a first geodetic position Qi of departure, an initial time L, a first initial altitude hi, a first initial speed of the aircraft Vï relative to the ground, that is to say geodetic, and a first wind speed Wi.
The second final state of the aircraft comprises a second geodetic position Qf of arrival at the target point, a final time t _f of constraint of arrival at the target point, a second final altitude hf, a second final speed of the aircraft Vf relative to the ground, that is to say geodesic, and a second wind speed Wf.
The final altitude hf and the second final speed of the aircraft ~ Vf relative to the ground at the instant and to the position constrained by the target arrival point is determined once the time constraint has been identified, ie on the basis of the known constraints of the approach procedure, or on the basis of the initially planned descent and approach profile of the aircraft
Thus are defined a required delay & t _required , equal to the difference t _f - t _t between the final constraint time t _f and the initial time q, and an altitude variation Lh _required , equal to the difference h _f - hi between the second final altitude hf and the first initial altitude hi.
The first step 4 is a step of calculating an energy differential of the aircraft in the air, designated by ΔΕ _α , between the first initial state of the aircraft and the second final state of the aircraft.
The second step 6, consecutive to the first step 4, is a step in which an adjustable model profile of altitude h _m (t) and speed in the air Va _m (t) of the aircraft is first provided . The adjustable model profile of altitude h _m (t) and of air speed Va _m (t) of the aircraft, or model of adjustable descent profile, corresponds to a predetermined strategy of air speed of l aircraft at minimum engine thrust, and uses one or more adjustable parameters. Then, during the same second step 6, the parameters of the adjustable model profile of altitude h _m (t) and of air speed Va _m (t) of the aircraft are adjusted so that the adjusted model profile obtained from altitude h (t) and from speed in air Va (t) of the aircraft ensures the consumption of the required variation of energy of the aircraft in air AE _a within the required time At _required , and the required altitude variation Ah _required within the required time to _required with a constant minimum engine thrust.
The third step 8, consecutive to the second step 6, is a step of determining a lateral geodesic trajectory of the aircraft, carried out from the adjusted altitude profile h (t), from the speed profile in the air adjusted Va (t) and knowledge of the wind speeds in the planned geography area of the aircraft crossing. The third step 8 is carried out by first calculating a desired lateral flight distance relative to the air mass, then a desired lateral ground or geodetic distance which incorporates the wind component, which makes it possible to ensure the reduction of energy required in the time required while remaining at minimum engine thrust.
Thus, the determination method 2 determines a combination of modification of lateral distance and adjustment of descent speed, making it possible to lose or save time compared to the required time delay, while remaining in a minimum engine thrust mode. The interest of the determination method 2 lies in the efficient and simple management of the compromise between speed adjustment and adjustment of the lateral component of the geodesic trajectory to remain energy efficient.
In fact, a loss of time can be ensured either by lengthening the trajectory, which requires additional energy, or by reducing speed, which requires more trajectory to reduce energy. It can therefore be applied by a combination of lengthening the lateral trajectory and reducing speed consistent, compatible with maintaining minimum thrust.
Similarly, a saving of time can be ensured either by a shortening of the trajectory, with risk of over-energy, or by an increase in speed which increases the drag and therefore makes it possible to reduce the energy over a shorter distance. It is therefore possible to find a combination of trajectory shortening and speed increase allowing the required time saving by maintaining the minimum thrust.
The method 2 for determining a profile of descent and rejoining in minimum thrust of a target point according to the invention therefore makes it possible to efficiently and simply calculate a maneuver of descent and rejoin in minimum engine thrust of a target point, and / or to exchange certain characteristic parameters between the air traffic controller and the crew, so as to satisfy, during the descent of the aircraft, a final time, statically or dynamically prescribed and provided by an external command, of arrival of the aircraft at the target point, remaining in an engine speed with constant and minimum thrust without using airbrakes, therefore without additional fuel consumption of the aircraft, or excess energy detrimental to the stabilization of the aircraft.
According to Figure 2, the first step 4 consists in determining the differential of the energy of the aircraft in the air ΔΕ _α as the difference EafEai between the energy of the aircraft in the air in the final state Eaf and the energy of the aircraft in the air in the initial state Eai.
The energy of the aircraft in air E _ai in the initial state is equal to the sum E _T i + E _W i of the total energy En of the aircraft in the initial state and of a first corrective term E _Wi of the effect of winds in the initial state on the air slope followed by the aircraft.
The energy of the aircraft in air E _a f at the final state is equal to the sum E _T f + Ewf of the total energy Etî of the aircraft at the final state and a second term Ewf correction of the effect of winds in the final state on the air slope followed by the aircraft.
The first step 4 includes first, second, third, fourth and fifth substeps 32, 34, 36, 38, 40.
In the first sub-step 32, the total energy En of the aircraft in the initial state is calculated from the first initial speed of the aircraft Vi relative to the ground, the first initial altitude hi and the mass m (t () of the aircraft at the initial instant ti according to the equation:
¹
En = 2 ^m ^ ^V i 'FmÇt ^ .g.hi g denoting the acceleration of Earth's gravity.
In the second substep 34, the total energy E _T f of the aircraft in the final state is calculated from the second final speed of the aircraft Vf relative to the ground, from the second final altitude hf and from the mass m (t /) of the aircraft at the final instant t _f according to the equation:
E _T f = ^V f ^{+ h} f
In the third sub-step 36, executed after the first sub-step 36, the first corrective term E _W i of the effect of the winds in the initial state on the air slope followed by the aircraft is calculated according to the equation:
Ewi = - -mÇt ^ -W ^ .W, in which Wi denotes the first wind speed observed at the first initial position of the aircraft
Then in the same third substep 36, the first corrective term
Ewî is added to the total energy E _T i of the aircraft in the initial state to obtain the energy of the aircraft in the air Eai in the initial state.
In the fourth sub-step 38, executed after the second sub-step 34, the second corrective term E _W f of the effect of the winds in the initial state on the air slope followed by the aircraft is calculated according to the equation:
Ewf = ~ 2 ~ -W ^) .Wf in which ÏÀfl denotes the second wind speed observed at the second final position of the aircraft
Then in the same fourth sub-step 38, the second corrective term E _Wf is added to the total energy E _T f of the aircraft in the final state to obtain the energy of the aircraft in air Eaf at the initial state.
In the fifth substep, step 40, the difference E _af - E _ai between the energy of the aircraft in the air in the final state Eaf and the energy of the aircraft in the air in the state initial E _ai is calculated.
It should be noted that generally speaking, knowing the current parameters of the state vector of the aircraft, at a current instant the total current energy of the aircraft E _T (t) is the sum of the kinetic energy and of potential energy according to the equation:
Where V _g (t) denotes the inertial speed, with respect to the ground, m (t) denotes the mass of the aircraft, g denotes the acceleration of terrestrial gravity, and h (t) denotes the current altitude of l 'aircraft.
The ground inertial speed V _g (tj is correlated to the air speed Va (t) of the aircraft using the wind direction and speed ÎV (t).
If we derive the current total energy, we get the equation:
By decomposing the inertial speed V _g (t) relative to the ground into a component of speed V _a (t) relative to the air mass and the speed ÎV (t) of the air mass, ie the wind, we get the equation:
We can then identify on this equation a specific residual energy term SEP (in English Specifies Excess Power) defined by
dt dt ’g dt and two corrective terms related to wind.
The integration of equation # 1 between any two instants t1 and t2 makes it possible to relate the total energy difference to the integration of the specific residual energy of the aircraft in the absence of wind, at which s' add two wind corrective terms.
The integrated equation is written:
^E Ti ^e tx = pSEPiùdt + —fe, ² -W, ² + 2V 2.W ₂ -2ν _α1 Υ (Equation # 3) mg ^{J (} i 2g
Thus, knowing the initial energy of the aircraft, as well as the current wind and the wind predicted at the point of arrival, we know how to determine what difference in energy must produce the integration of the SEP in the air between the instants initial and final, this MS in the air being calculated without taking the wind into account.
Note that the wind terms in the formula in equation # 3 only translate the addition of wind and air speed to form ground speed, but do not account for the effect of wind on the distance covered. This effect of the wind can be taken into account in the fourth step 10 of method 2.
The residual energy is also determined by the balance between the engine thrust T (in English Thrust) and the drag D (in English Drag) according to the expression:
SEP (t) = E _a (t) ^T - ^D - (Equation # 4)
The thrust T depends on the engine speed and the altitude while the drag depends on the altitude, the air speed and the air slope which together determine the incidence of the descent.
Note that the two wind terms in the formula for equation # 3 only translate the addition of wind and air speed to form ground speed.
On the other hand, equation # 4 expressed in the air mass obliges to introduce a term related to the wind gradient, or more exactly, its application requires to introduce in equation # 2 of expression of the MS related to the wind gradient. The expression of MS then becomes:
^E a dV dh V dW,
SEP (t) = ——- + - + —- (Equation # 5) g dt dt g dt
Likewise, equation # 4, which is based on a balance between lift and weight, must be corrected by the apparent weight induced by an additional load factor when the aircraft is making a turn.
The effect of the wind gradients and of the apparent speed due to the turns, linked to the lateral trajectory is ignored in the first step 4 but can be reintroduced in a second step described below.
Knowing the first initial altitude, the first initial air speed, the second final altitude and the second final air speed, it is possible to generally determine a profile at altitude h (t) and at descent air speed V _a (t ) corresponding to a particular descent strategy, for which the integral of the SEP, taking into account adapted acceleration or deceleration phases, makes it possible to obtain the energy differential within the required time. In general, this descent strategy can be defined by a descent profile, parameterized using a set of parameters forming degrees of freedom of the descent profile, so as to allow, by adjusting these parameters, obtain the energy differential within the required time, according to the digital optimization methods known from the state of the art.
For example, when we go to constant and minimum engine speed (regime called in English “idle”), for phases of descent at constant speed or constant acceleration or constant deceleration, we can approximate that the variation of SEP over any time interval [t1, t2], t1 being strictly less than t2, on which the phase is defined, is linear, and we then obtain the relation:
-4-- 4) = (¼ - / ¾) + ^a (Equation # 6)
2g
Three basic cases can then arise:
.- a first case of a descent at constant bounded acceleration, .- a second case of a descent at constant CAS speed or possibly at constant Mach;
.- a third case of descent with deceleration at constant energy ratio.
According to FIG. 3, the second step 6, consecutive to the first step 4, comprises a first sub-step 52 and a second sub-step 54.
The first sub-step 52 is a step of providing an adjustable model profile of altitude h _m (t) and speed in the air Va _m (t) of the aircraft.
During the second sub-step 54, the parameters of the adjustable model profile of altitude h _m (t) and of air speed Va _m (t) of the aircraft are adjusted so that the adjusted model profile obtained of altitude h (t) and of speed in air va (t) of the aircraft ensures the consumption of the required variation of energy of the aircraft in air AE _a within the required time ùt _required , and the required altitude variation hf-hi within the required time with constant and minimum thrust engine speed.
The adjustable model profile of altitude h _m (t) and air speed Va _m (t) of the aircraft is broken down into or formed by a temporal succession of a number K, greater than or equal to 2, of adjustable elementary profiles of altitude h _m (k, t) and of air speed Va _m (k, t) of the aircraft, the index k being an index identifying the order of temporal succession of the adjustable elementary profiles h _m (k, t), Va _m (k, t) between 1 and K.
The elementary profile h _m (1, t) and Va _m (1, t) evolves over a first elementary time interval IT (1) comprised between the initial time ti and a first intermediate time t (2) respectively forming the times associated with the first initial state and a first intermediate state of the aircraft.
For k varying between 2 and N-1, the elementary profile h _m (k, t) and Va _m (k, t) evolves over a k-th elementary time interval IT (k) comprised between a (kl) -th time intermediate t (k) and a k-th intermediate time t (k + 1) respectively forming the times associated with the (k-1) th intermediate state and the k-th intermediate state of the aircraft. and
The elementary profile h _m (N, t) and Va _m (N, t) evolves over an N-th elementary time interval IT (N) between the (Nl) -th intermediate time t (N) and the final time tf respectively forming the times associated with the (Nl) th intermediate state and the second final state of the aircraft.
Two consecutive intervals IT (k), IT (k + 1) for k varying from 1 to N-1 are contiguous.
The adjustable profiles h _m (k, t) and Va _m (k, t), for k varying from 1 to N correspond to phases Φ (&) of descent in constant and minimum engine speed, the phases of descent in engine speed constant and minimum being included in the unit formed by the phases of descent at constant CAS speed, the phases in constant acceleration and the deceleration phases with constant ER energy ratio.
For each descent phase 4> (fc) and the corresponding adjustable profile h _m (k, t) and Va _m (k, t), k varying from 1 to N, the variation of the residual energy in the air SEP _m (k, t) along the elementary interval IT (k) is linear, the residual energy in the air being defined by the equation:
SEP _m (k, t)
Vam (k> 0 dV _am (k, t) g dt dh _m (k, t) dt where g denotes the acceleration of gravity near the surface of the Earth.
For k varying from 1 to N, the integral of the residual energy SEP _m (k, t) 5 along the elementary interval IT (k) is equal to the energy differential of the aircraft in the air AE _am (k) on the k-th interval IT (k) between the state of the aircraft at time t (k) and the state of the aircraft at time t (k + 1), divided by the weight of the aircraft as a product of the aircraft's mass and the following constant:
Egm (k, t (k + 1)) - E _am (k, t (k) _ SEP _m (k, t (kf) + SEP _m (k, t (k + 1) mg 2 rt (k + l )
SEP _m (k, t) dt = M
For each descent phase Φ (£) and the corresponding adjustable profile h _m (k, t) and Va _m (k, t), k varying from 1 to N, the start time of the interval IT (k) , t (k), the end time of the interval IT (k), t (k + 1), the altitudes h _m (t (k)), and h _m (t (k + 1)), the speeds of the aircraft in the air Va _m (k, t (k)) and
Va _m ((k, t (k + 1)), the residual energies SEP _m (k, t (k)), SEP _m (k, t (k + 1)), corresponding respectively to the two instants t (k) and t (k + 1) are connected by the relation:
SEP _m (k, t (k)) + SEP _m (k, t (k + 1) = [h _m (t (k + 1) - h _m (t (k)] +. (T (fc +1 ) - t (fc))
Vam ² (k, t (k + 1)) - Vam ² (k, t (k))
7g
For k varying from 1 to N, when the adjustable profiles h _m (k, t) and Va _m (k, t) correspond to a phase <î> (k) of descent in bounded constant acceleration and in constant and minimum engine speed , the duration At _m (k) of the k-th elementary interval IT (t) and the altitude variation âh _m (k) over said interval IT (k) verify the equations:
at _m (k)
V _am (k, t (k + 1)) ^ am (k, t (k)) and / SEP _m (k, tw) + sEP _m (k, t (k + D) _ y _am (t (fc )) + v _am (t (fc + i)) . çy _am Ç _t ç _k + _X )) _ K _am (t (k))) 2Λ 2o}
For k varying from 1 to N, when the adjustable profiles h _m (k, t) and Va _m (k, t) correspond to a <t> (k) phase of descent at constant CAS or Mach speed and in constant engine speed and minimal, the duration at _m (k) of the k-th elementary interval IT (t) and the variation in altitude Ah _m (k) over said w interval IT (k) verify the equations
Ah _m (k) = h _m (k, t (k + 1)) - h _m (k, t (k)) and
At ^ C / c) = (fi , Vam ² (t (k + 1) - Vam ² (t (k))
SEP _m (k, t (k)) + SEP _m (k, t (k + 1)) ' ⁺ 2g J
For k varying from 1 to N, when the adjustable profiles h _m (k, t) and Va _m (k, t) correspond to a phase <î> (k) of descent in deceleration with constant energy ratio ER and in constant and minimum engine speed, the duration At _m (k) of the k-th elementary interval IT (t) and the variation in altitude
Ah _m (k) over said interval IT (k) verify the equations:
At _m (k) / Vam ² (t (k + 1) - Vam ² (t (k)) ”ER. (SEP _m (k, t (k)) + SEP _m (k, t (k + 1 ))) 'VS) and _f (1 - ER) (Vam ² (t (k + 1)) - Vam ² (t (k))) = _ER . The parameters of the adjustable profiles h _m (k, t) and Va _m (k, t) are adjusted so that the sum of the interval times ât _m (k) for k varying from 1 to N being equal to the duration required at t _required , and the sum of the altitude variations at h _m (k) for k varying from 1 to N is equal to the difference between the first initial altitude hi and the second final altitude hf.
It should be noted that possibly, depending on the SEP and the energy ratio, the deceleration with constant energy ratio can be bounded by criteria of passenger comfort, similarly to the case of constant bounded acceleration.
According to Figure 4 and a first example of a preferred descent strategy, an adjusted model profile 72 of altitude h (t) (curve 74) and speed in air Va (t) (curve 76) is illustrated as being the profile of altitude and speed in the air, obtained after adjustment of the parameters of an adjustable model profile of altitude h _m (t) and Va _m (t) associated with the descent strategy.
The descent strategy selected here to determine the adjusted profile here typically comprises three successive phases:
.- a first phase Φ (1) of acceleration / deceleration to a desired CAS speed, then .- a second phase Φ (2) at the desired CAS speed (in English Calibrated Air Speed) constant, then .- a third phase Φ (3) acceleration / deceleration to the final speed.
These three phases Φ (1), Φ (2), Φ (3) are illustrated by a first series of three sections 82, 84, 86 on curve 74 of the altitude profile h (t) and a second series 92, 94, 96 on the curve of the air speed profile Va (t).
The desired constant CAS speed, and the durations of the three phases are adjusted so as to satisfy the total duration constraint required as well as the duration of altitude variation constraint hi-hf. These quantities form the set of parameters to be adjusted in the adjustable model profile of altitude h _m (t) and Va _m (t) associated with the descent strategy.
The value of SEP as well as the air speed value associated with a given CAS speed, being dependent on the altitude, it is possible to adjust the values of SEP and air speed once the variation in altitude is known. However, the variations are small and depending on the precision desired, this adjustment is generally unnecessary.
The formulas described above, applied for N equal to 3, make it possible, for a fixed desired CAS speed setpoint, to determine the altitude variations necessary for the acceleration and deceleration phases, as well as the flight altitude variation at constant CAS. We then obtain a speed profile allowing to pass from the total energy (altitude and speed) initial to the total energy final, as well as the time required to carry out each of the phases of acceleration, deceleration, and descent at speed. Constant CAS. This calculation can be repeated iteratively for different values of desired CAS speed, so as to find the target speed achieving the desired delay, according to the Newton or string algorithm.
The initial value of CAS can optionally be determined using time of flight profiles at minimum and maximum speed, according to the speed search method described in patent application US8332154. It should be noted that an iteration will remain necessary in order to satisfactorily adjust the altitude variation and the acceleration and deceleration phases.
As a variant of this first example, it is also possible to vary the instant of deceleration between the current CAS speed and the final CAS speed.
According to a second example of a descent strategy, an adjusted model profile of altitude h (t) and air speed Va (t) is obtained after adjusting the parameters of an adjustable model profile of altitude h _m (t ) and of air speed Va _m (t), associated with this descent strategy of a second type
The descent strategy selected in this second example to determine the adjusted profile here typically comprises three successive phases:
a first phase Φ (1) at the initial CAS speed on a first tranche of altitude A / i _m (l) with an adjustable duration making it possible to vary an instant of start of deceleration, then .- a second phase Φ (2 ), decelerating from the initial CAS speed to the final CAS speed, then .- a third phase Φ (3) of descent at the final CAS speed to the final altitude,
The variation in altitude Δ / ι ^ ζΙ) before deceleration is adjusted iteratively to obtain the duration of the first phase.
Thus at the end of the second step 6, there is a time profile of air speed Va (t) which has the property of ensuring the required altitude variation within the required time, while maintaining a minimum thrust.
This speed profile Va (t) also determines the altitude profile h (t) thanks to the relationship which links variations in altitude and variation in time.
Finally, the air slope y (t) which is a function of h (t) and Va (t) according to the dh relation siny (t) = - (t) makes it possible to obtain a distance traveled curve
Go
Da in the air mass.
Once the speed profile Va (t) and the flight time have been known, a horizontal air distance traveled Da is obtained. The cumulative effect of the wind W must then be taken into account to determine the horizontal or lateral distance from the ground Dg.
By considering Qi and Qf the initial and final geodesic positions of the aircraft, the vector is defined by the relation:
If this equation is brought back to its horizontal component we obtain:
(Equation # 7)
P, and Pf designating the horizontal geodesic positions of initial departure and final arrival, determined from initial and final geodesic positions Qi and Qf, V _a , hor designating the horizontal component of the air speed, and W _h01 î the component horizontal wind.
The horizontal air speed V _a , h _Or has the same heading as the air speed V _a , and a module multiplied by the cosine of the air slope y (t), and the wind W is reduced to its horizontal component W _h .
According to FIG. 5 and a first embodiment 102 of the third step 8, it is assumed at least as a first approximation that in the geographic area considered for movement of the aircraft, the wind speed and direction depend only on the 'altitude. It is then possible to evaluate the second term of equation # 7 independently thanks to the knowledge of the altitude profile h (t).
According to FIG. 5, the third step 102 comprises a first sub-step 104, a second sub-step 106, a third sub-step 108, and a fourth step 110, executed successively.
During the first sub-step 104, horizontal start and finish positions, Pa1 and Pa2, within the mass are determined from horizontal start and finish geodesic positions, P, and P _f , and the horizontal wind speed W _hor (hj assuming that the wind speed and direction depend only on the altitude h and using the relation:
çt2
Pflf - W _hor (h (iï) dt Jti
Pai ^ af
Equation # 8
It should be noted that the first sub-step can be implemented for any segment P1P2 of the horizontal ground or geodesic trajectory P (t), for which the altitude and the time of passage at one of the ends P1 or P2 is known.
During the third sub-step 108, a required lateral distance to travel D _a is determined from the speed profile of the aircraft in the air Va (t) and the air slope y (t) using l 'equation:
£> _a = V _a (t) .cos (y (t)) dt Jti
During the same second sub-step 106, a lateral trajectory Pa (t) in the air is determined joining the horizontal positions of departure and arrival, P _ai and P _af , and taking into account the initial velocity vectors and final in the air, the length of the lateral trajectory in the air Pa (t) being constrained by being equal to the lateral distance required to travel D _a The calculation executed in the second sub-step can use defined principles in several methods for lateral spacing maneuvers between aircraft, as described in patent applications FR2983619 or US8862373 and FR2926156 or US8078341.
It is also possible to apply very varied geometries according to the phases of the descent, and the maneuvers envisaged to adjust the trajectory laterally, so as to cover the required distance in the air mass.
During the fourth sub-step 110, a geodesic lateral trajectory P (t) is determined joining the horizontal positions of departure and arrival, Pa1 and Pa2 and taking into account the initial and final velocity vectors in the air, the length of the geodesic lateral trajectory P (t) being constrained by being set equal to the required lateral distance to travel D _a .
According to FIG. 6, an example of implementation of the third step according to the first embodiment is illustrated through the drawing of a horizontal air path 122, calculated from knowledge of the geodesic positions Pi and Pf, d ' an altitude profile h (t) and air speed determined in the second step 6, and knowledge of the wind, and through a horizontal or lateral geodesic trajectory 124.
The lateral air trajectory 122 is divided into three first segments 126, 128, 130 delimited by the successive passage points P ,, Pa11 Pa2, Paf The horizontal geodesic trajectory 124 is divided into three second segments 132, 134, 136 delimited by the points of successive passages P ,, Ρ _Ί , P2 and Pf.
The horizontal geodesic trajectory 124 is obtained here from the lateral air trajectory 122 by sliding the points P _a i, P _a2 , Paf respectively according to the vectors W /, + W ₁₂ , Üçf + Wi ₂ + W ₂ ' _f , the vectors. W ₂ ÿ being respectively the sums of the wind between the instants t, and ti, t-ι and t ₂ , t ₂ ettf.
According to FIG. 7 and a second embodiment 152 of the third step 8, the third step 152 allows, knowing a preliminary adjustable lateral trajectory, and possibly having a more precise wind model, depending on the horizontal position, of the altitude and possibly time, to integrate over time the position of the aircraft, by applying the altitude profiles h (t) and air speed Va (t), and evaluating the inertial speed at all times of the aircraft resulting from air speed and wind speed. The difference between the integrated horizontal geodetic distance or the final geodetic stopping position obtained during integration and the required horizontal geodetic distance or final position makes it possible to determine a lateral adjustment of the lateral geodetic trajectory.
The third step 152 comprises a first sub-step 154, a second sub-step 156, and a third sub-step 158, executed successively.
In the first sub-step 154, a preliminary lateral trajectory of a predetermined type adjustable by the modification of a parameter, and a wind model depending on the altitude and possibly the horizontal position and possibly the time are provided.
Then in the second sub-step 156 the at least one parameter of the adjustable preliminary lateral trajectory is modified so that the geodetic trajectory ends at the final arrival target point Qf taking into account the winds and the descent profile calculated in the second step.
Then, in the third sub-step 158, a required or desired horizontal geodesic distance D is determined from the altitude profiles h (t) and of the speed of the aircraft in the air Va (t), by evaluating at each time t the module | K _{5; h} or | the horizontal geodetic speed of the aircraft from the air speed Va (t) and components of the wind speed (XW (t), TW (t)), and by integrating over time and along the lateral trajectory adjusted the module of the horizontal geodetic speed according to the equations:
rtf rtf ^D = Ifc.U ^dt = NVa ² -XW ² (t) + TW (t)) dt ^J ti Jti
XW (t) and TW (t) designating respectively the transverse component and the longitudinal component of the wind at time t.
By taking inspiration from known methods of spacing between aircraft, one can for example consider:
adjusting a turn to a specified point, along the planned route of the aircraft, .- Adjusting a turn to a specified point, along a specified heading,
It is also possible to apply this second embodiment of the third step 152 to the approach phases with capture of the final approach axis. In this case, you can dynamically adjust the capture heading to modify the length of the trajectory, or alternatively dynamically calculate the turning point along the current heading, to capture the final axis, i.e. at a specified distance from the capture point of the final slope, said capture point being defined by a FAF point (in English Final Approach Fix) or by an FCA altitude (in English Final Capture Altitude), or to ensure a capture of the axis at a specified angle such as 45 ° or 90 °. Each of these maneuvers determines a degree of freedom or an adjustment parameter, in the form of a distance along an axis or a heading, which is varied to correct the error of length or lateral geodesic distance traveled.
According to FIG. 8, a first example of implementation of the third step according to the second embodiment is illustrated through the drawing of a horizontal air path 172, calculated from knowledge of the geodesic positions Pi and Pf, d a profile of altitude h (t) and of air speed determined in the second step 6, of knowledge of the wind and of an adjustable preliminary lateral geodetic trajectory 174, and through an adjusted lateral geodetic trajectory 176.
The lateral air trajectory 172 is divided into three first segments 178, 180, 182 delimited by the successive waypoints P ,, Pa1, PaTurn, Paf The preliminary adjustable lateral geodesic trajectory 174 is divided into three second segments 184, 186, 188, delimited by successive crossing points P ,, Pi, Po.Turn and Pf.
The adjusted lateral geodesic trajectory 176 is broken down into three third segments 190, 192, 194, delimited by the successive crossing points P ,, Pi, P _Tu m and Pf.
The lateral geodesic trajectories 174, 176 are both a lateral trajectory of the “follow the road then turn” type (in English “follow route then turn”), and each comprise a turning point, designated respectively by Po, Turn and Pïum, these two turning points being aligned with the point P-ι.
The two lateral geodesic trajectories 174 and 176 of the same type are each characterized by the distance from their turning point to the point Pi and their turning angle to their respective turning point.
Thus, the distance from the turning point relative to point P1 and the turning angle constitute the adjustable parameters or degrees of freedom of this first type of trajectory.
The horizontal geodesic trajectory 176 is obtained here from the lateral air trajectory 172 by respectively dragging the points P _a i, PaTurn 2, Paf according to the vectors + W _ir ', 1¾ + + WTy / = Ûfe, the vectors Wf, M7 _1T ', W _ri (not shown but deductible from Üfe) being respectively the sums of the wind between the instants t, and t-ι, ti and trum, trum ettf.
According to FIG. 9, a second example of implementation of the third step according to the second embodiment is illustrated through the drawing of a horizontal air trajectory 202, calculated from the knowledge of the geodesic positions Pi and Pf, d '' a profile of altitude h (t) and air speed determined in the second step, of knowledge of the wind and of a preliminary adjustable lateral geodesic trajectory 204 of a second type, and through a geodesic trajectory 206 adjusted side.
The lateral air path 202 is divided into three first segments 208, 210, 212 delimited by the successive passage points P ,,
PaTurni Pa2, Paf ·
The preliminary adjustable lateral geodesic trajectory 204 is divided into three second segments 214, 216, 218, delimited by the successive crossing points P ,, Po.Tum, P2 and Pf.
The adjusted lateral geodesic trajectory 206 is divided into three third segments 220, 222, 224, delimited by the successive crossing points P ,, P _Tu m, P2 and Pf.
The lateral geodesic trajectories 174, 176 are both a lateral trajectory of the type "follow a course then turn" (in English "heading then turn"), and each comprise a turning point, designated respectively by Po.Turn and P _Tu m ·
Thus, the heading angle followed (in English "heading") and the angle of turn constitute the adjustable parameters or degrees of freedom of this second type of trajectory.
The horizontal geodesic trajectory 206 is obtained here from the lateral air trajectory 172 by sliding the points PaTum, P _a2 , P _a f respectively according to the vectors - W _2f , w / _f , the vectors ÏV ^, W ₂ f,
ÏÏÇ being respectively the sums of the wind between the instants t, and t-rum, tïurn and t ₂ , t ₂ and tf.
According to FIG. 10, the horizontal component 232 of the initial adjustable geodesic trajectory corresponding to a third joining strategy is illustrated in which the capture of the final axis 234 of alignment with the landing runway 236 is adjusted in distance with a distance margin or specified capture distance. The adjustable parameter of the third step here is the capture distance.
According to FIG. 11, the horizontal component 242 of the initial adjustable geodetic trajectory corresponding to a fourth joining strategy is illustrated in which the capture of the final axis 244 of alignment with the landing runway 246 is adjusted in distance with a specified capture angle. The adjustable parameter of the third step is the capture angle here.
According to FIG. 12, the horizontal component 252 of the initial adjustable geodetic trajectory corresponding to a fifth joining strategy in which the capture of the final axis 254 of alignment with the landing runway 256 is adjusted in distance by modification of the heading . The adjustable parameter of the third step here is the heading angle.
According to FIG. 13, the fourth step 10, consecutive to the third step 8, is configured to correct the profiles of altitude h (t) and of air speed Va (t), and of the lateral geodesic trajectory P (t), determined respectively in the second and third steps 6, 8, according to corrections which take into account, a first effect of the wind gradients in the calculation of the residual energy in the air SEP and / or a second effect e ₂ (t) turns on the load factor which modifies the apparent mass in the calculation of the variation of the residual energy in the air SEP (t).
Indeed, during the calculation of the altitude and speed profile in the air mass used, several approximations were made concerning the non taking into account of the effect of the wind gradients in the calculation of the SEP, and / or the effect of turns on the load factor, which modifies the apparent mass in the calculation of SEP, due to the fact that these effects can only be really calculated on an assumption of lateral trajectory. However, taking them into account, by modifying the SEP values, influences the altitude and speed profile that we are trying to determine more precisely.
The general expression for the residual energy SEP (t) in which these corrections are taken into account is written in the form;
SEP (t) = g
VaW) (dV _a (t) where g denotes the acceleration of gravity near the surface of the Earth.
According to FIG. 13, the fourth step 10 is an iterative process, comprising first, second, third, fourth substeps 252, 254, 256, 258, executed in a loop 260.
The first sub-step 252, executed initially at the end of the third step 8 and after the fourth sub-step 258 when at least one iteration has been decided during the third sub-step 256, consists in conventionally determining a time evolution of an aircraft state vector including at least the altitude h (t), the speed of the aircraft in the air Va (t), the lateral geodesic distance traveled D (t) along of the current geodesic trajectory P (t), initially determined at the start of a first iteration in the third step 8 or determined during the fourth substep 258 of the fourth step 10, taking into account the wind gradients and the load factor of the turns in the calculation of the change in residual energy SEP (t) until either the final position or the final altitude is reached at a stopping point of the current geodetic trajectory e. A conventional determination of the time evolution of an aircraft state vector is described for example in the thesis of Wissem Maazoun, entitled "Design and analysis of a system for optimizing flight plans for airplanes" and presented in April 2015 at the University of Montreal.
The second sub-step 254, executed after the first sub-step 252, consists of the fact that gross deviations ÔD ₁ , ôtq, ôh, ÔV _a , concerning the lateral geodesic distance traveled, time, altitude, speed in the air are evaluated between the state of the aircraft, considered at the stopping point and calculated by taking into account the correction effects, and the desired final state, and in that refined deviations SD ₂ , ₂ , concerning the lateral geodesic distance traveled, the time is evaluated as a function of the gross deviations ÔD ₁ , ôt _± , between the state of the aircraft, considered at the stopping point and calculated taking into account the correction effects, and the desired end state,
The third sub-step 256 of testing and deciding to execute an iteration of the loop 260, executed after the second sub-step 254, consists in that the refined deviations ÔD ₂ , ot ₂ of lateral geodesic distance traveled and of arrival time at the stopping point are compared with a stopping threshold for leaving the loop σ, a connection is made to the fourth sub-step 258 when at least one of the refined deviations ÔD ₂ , ôt ₂ is greater or equal to the stop threshold σ, and a stop of the fourth step is carried out when the two refined deviations ÔD ₂ , ôt ₂ are strictly less than the stop threshold σ. The stop threshold σ is a tolerance threshold, dimensioned according to the magnitude of the additional thrust or drag corrections deemed admissible during the maneuver of the aircraft. It should be noted that the iterations can also be stopped when the feasibility limits are reached, either laterally when the distance obtained is the most direct distance possible for the maneuver considered, or in the speed range when the speed obtained is the speed limited by the flight envelope.
The fourth sub-step 258, executed when at least one of the refined deviations ÔD ₂ , ôt ₂ is greater than or equal to the stop threshold σ consists in that the current profile of altitude h (t) and speed in l air Va (t) is readjusted taking into account the refined time difference and reusing the profile adjustment process of the second step 6, then the lateral trajectory maneuver is readjusted taking into account the difference in distance refined and reusing the method of adjusting the lateral trajectory of the third step to obtain an updated current geodetic trajectory.
Preferably, the refined deviations ÔD ₂ , 5t ₂ of geodesic distance traveled and of time of arrival at the stopping point are functions of the gross deviations ÔD _r ,, between the state of the aircraft, considered at the point of stop and calculated taking into account the correction effects, and the desired final state, according to the relationships:
and ôD ₂ - ÔD ₁ + -. all ₂ . Vp
Vf and SEP designating respectively the final speed and the variation of residual energy at the stop point P (iy).
Indeed, the new preferred time difference ôt ₂ makes it possible to adjust the definition of the altitude and speed profile h (t) and Va (t), according to a correction similar to that applied in the initial search for these profiles carried out in the second and third steps 6, 8. The change in profile obtained, which aims to modify the duration of energy dissipation, will also result in a modification of the required distance. However, an increase (respectively a reduction) in the dissipation time generally requires a reduction (respectively an increase) in the speed. The effects on the lateral distance traveled are therefore opposite, and as a first approximation, one could estimate that they compensate and simply apply a correction of length ôD _x on the lateral trajectory. However, considering that speed has a quadratic effect on energy dissipation, the drag varying like the square of speed, and linear over length, more efficient convergence is ensured by applying the preferred distance correction δϋ ₂ .
According to FIG. 14, a system 302 for determining a descent profile and rejoining in minimum thrust of a target point by an aircraft 304 comprises a database 306 of the performances of the aircraft, a means 308 of supplying meteorological data of the environment in which the aircraft is operating, an air control ground station 310 to provide a required final time t _f or a required time delay At _required , of arrival of the aircraft 304 at the target point, and one or more electronic computers 312 for calculating the profile of descent and rejoining in minimum thrust from the target point.
According to FIG. 14 and in particular, the at least electronic computer 312 for calculating the profile of descent and joining in minimum thrust of the target point is the flight management system FMS (in English Flight Management System), and the means 308 for providing meteorological data comprises a database or memory for storing meteorological data on board the aircraft.
The descent profile, continuously monitored in an engine speed at constant and minimum thrust, is defined from a first initial state of aircraft 304 to a second final state of aircraft 304 temporally constrained by time of final arrival tf at the target point or a required time delay At.
The first initial state of the aircraft comprises a first starting geodesic position Qi, an initial time ti, a first initial altitude hi, a first initial speed of the aircraft VÎ relative to the ground and a first wind speed WÎ,
The second final state of the aircraft comprises a second geodetic position Qf of arriving at the target point, a final time tf of constraint, a second final altitude hf, a second final speed of the aircraft Vf relative to the ground and a second speed Wf wind,
The determination system 302 is configured to:
.- in a first step, calculate an energy differential of the aircraft in the air AE _a between the first initial state of the aircraft and the second final state of the aircraft, then .- in a second step, provide a parametric model of altitude profile h (t) and of speed in air Va (t) of aircraft 304 corresponding to a strategy of speed in air with permanent minimum engine thrust, then adjust parameters of said parametric model so that the adjusted parametric model of altitude profile h (t) and air speed va (t) of the aircraft ensures the consumption of the energy variation of the aircraft in l 'air AE _has in the required time At _required , and the required altitude variation hf-hi in the required time with permanently minimal engine thrust; then in a third step, determining a geodesic trajectory of the aircraft and a lateral geodesic trajectory from a type of lateral maneuver, from the adjusted altitude profile h (t), from the adjusted air speed profile going (t) and knowledge of the wind speeds in the expected geography area of the aircraft crossing.
According to a first particular system configuration 302 of FIG. 14 and a first operating mode, the aircraft 304 comprises a first computer, here the FMS computer, configured to calculate on board an intermediate CAS descent speed required and a required flight distance, and first transmission means 322 for sending these two requirement parameters, and the air traffic control station 310 comprises second transmission means 324 for receiving the required intermediate CAS descent speed and the required flight distance and sending to the aircraft 304 instructions for defining a lateral trajectory and speed, said instructions being determined by a second computer of the ground station to ensure the required flight distance and intermediate speed.
According to a second configuration, the ground station is configured to send to the aircraft, in addition to the required delay, a point of convergence along the flight plan, and the first computer of the aircraft is configured to determine the intermediate speed CAS and the required geodetic distance, and identify a turning point, either along a current heading maintenance by a course alignment, or along the current flight plan, by shortening of the trajectory, followed by a direct flight to the focal point. The turning point is then transmitted to the ground, the flight plan modified accordingly, and lateral and speed guidance is activated on board.
According to a third configuration, the ground station is configured to calculate the required intermediate CAS descent speed and a required flight distance, to provide the ground operator with a lateral trajectory offering the required flight distance, and to transmit to the crew under operator control said lateral trajectory, in the form of a new flight plan, of a required trajectory, or of a succession of heading instructions, making it possible in all cases to ensure synchronization in the most economically favorable conditions for the aircraft.
In general, the aircraft is included in all of the planes piloted on board manually or in automatic mode and drones piloted remotely manually or in automatic mode.
In general, the at least electronic computer for determining a descent profile and joining in minimum thrust of a target point is:
.- an electronic computer integrated into an FMS flight management system, or .- an EFB or any on-board navigation aid computer but not integrated into the aircraft avionics, or .- a computer integrated into an ground station for air control, decision support for a controller, or .- a computer integrated in a ground station for mission management of a drone.
The method and system, described above, of determining a descent profile and joining in minimum thrust of a target point by an aircraft, therefore make it possible to satisfy a time constraint at a target point of the descent, while maintaining minimum thrust and securing the final stabilization of the aircraft before landing. This process takes into account the descent performance of the aircraft, as well as the impact of the wind during the descent. It can be applied in any configuration of trajectories making it possible to introduce flexibility over the length of the lateral trajectory, and operational examples of such trajectories are:
.- adjusting a turn to a specified point, along the planned route of the aircraft, .- adjusting a turn to a specified point, along a specified heading, .- l '' adjustment of the catch of the final approach axis by modification of the capture course, .- adjustment of the capture of the final approach axis by maintaining the course up to a turning point, then capture at a specified angle, adjusting the capture of the final approach axis by maintaining the heading to a turning point, then capturing with a specified distance margin.

权利要求:
Claims (5)
[1" id="c-fr-0001]
CLAIMS .1 Method of determining a descent profile and joining in minimum thrust of a target point by an aircraft,
The continuously descending profile in minimum thrust being defined from a first initial state of the initial aircraft to a second final state of the time-constrained aircraft,
The first initial state of the aircraft comprising a first geodetic starting position Qi, an initial time ti, a first initial altitude hi, a first initial speed of the aircraft VÏ relative to the ground and a first wind speed Wï,
The second final state of the aircraft comprising a second geodetic position Qf of arrival at the target point, a final time tf of constraint, a second final altitude hf, a second final speed of the aircraft ~ Vf relative to the ground and a second wind speed Wf,
Said method being characterized in that it comprises a first step (4) of calculating an aircraft energy differential in air ΔΕ _α between the first initial state of the aircraft and the second final state of the aircraft; and a second step (6), consecutive to the first step consisting in. * providing an adjustable model profile of altitude h _m (t) and of speed in air Va _m (t) of the aircraft, corresponding to a strategy of descent into the air which permanently ensures an engine speed at minimum thrust and using one or more adjustable parameters, then adjusting the adjustable parameter (s) so that an adjusted profile of altitude h (t) and speed in the air va (t) of the aircraft ensures the consumption of the energy variation of the aircraft in the air AE _a within the required time & t _required , and the required altitude variation hi - hf in the time required with constant and minimum thrust engine speed; and a third step (8), consecutive to the second step, of determining a lateral geodesic trajectory P (t) of the aircraft from the adjusted altitude profile h (t), of the speed profile in the adjusted air Va (t) and knowledge of the wind speeds in the expected geography area of the aircraft crossing.
.2 Method for determining a profile of descent and rejoining in minimum thrust of a target point by an aircraft according to claim 1, in which the first step (4) consists in determining the energy differential of the aircraft in air ΔΕ _α as the difference E _ai - E _af between the energy of the aircraft in the air in the initial state E _ai and the energy of the aircraft in the air in the state final E _af , the energy of the aircraft in air E _ai in the initial state being equal to the sum Etî + E _Wi of the total energy Et, of the aircraft in the initial state and d a first corrective term Ewî of the effect of the winds in the initial state on the air slope followed by the aircraft, and the energy of the aircraft in the air Æ _{a /} in the final state being equal to the sum Etî + E _Wf of the total energy E _T f of the aircraft in the final state and a second corrective term E _W f of the effect of the winds in the final state on the air slope followed by l '' aircraft, with and and
E _T f = + m (t _f ) .gh _f and (t _f ). Wf - (Vf - W _f ). W _f and m (tf) denoting the mass of the aircraft respectively at the initial instant f and the final instant t _f .
.3 Method for determining a profile of descent and joining in minimum thrust of a target point by an aircraft according to any one of claims 1 and 2, in which the modeled adjustable profile of altitude h _m (t) and speed in air Va _m (t) of the aircraft is decomposed into a temporal succession of a number N, greater than or equal to 2 3, of adjustable elementary profiles of altitude h _m (k, t) and in air speed Va _m (k, t) of the aircraft, the index k being an index identifying the order of temporal succession of the adjustable elementary profiles h _m (k, t), Va _m ( k, t) between 1 and N; and the elementary profile h _m (1, t) and Va _m (1, t) evolves over a first elementary time interval IT (1) comprised between the initial time ti and a first intermediate time t (2) respectively forming the associated times the first initial state and a first intermediate state of the aircraft; and for k varying between 2 and N-1, the elementary profile h _m (k, t) and Va _m (k, t) evolves over a k-th elementary time interval IT (k) between one (kl) -th intermediate time t (k) and a k-th intermediate time t (k + 1) respectively forming the times associated with the (k-1) -th intermediate state and the k-th intermediate state of the aircraft; and the elementary profile h _m (N, t) and Vam (N, t) evolve over an N-th elementary time interval IT (N) comprised between the (Nl) -th intermediate time t (N) and the final time tf respectively forming the times associated with the (Nl) th intermediate state and the second final state of the aircraft; and two consecutive intervals IT (k), IT (k + 1) for k varying from 1 to N-1 are contiguous, the adjustable profiles h _m (k, t) and Va _m (k, t), for k varying from 1 to N correspond to descent phases at constant and minimum engine speed, the descent phases at constant and minimum engine speed being included in the assembly formed by the descent phases at constant CAS speed, the phases under constant acceleration and the deceleration phases at constant ER energy ratio.
.4 Method of determining a descent profile and joining in minimum thrust of a target point by an aircraft according to claim 3, in which for each descent phase Φ (/ ς) and the corresponding adjustable profile h _m ( k, t) and Va _m (k, t), k varying from 1 to N, the start time of the IT interval (k), t (k), the end time of the IT interval ( k), t (k + 1), the altitudes h _m (t (k)), and h _m (t (k + 1)), the speeds of the aircraft in the air Va _m (k, t ( k)) and Va _m ((k, t (k + 1)), the residual energies SEP _m (k, t (k)), SEP _m (k, t (k + 1)), corresponding respectively to the two instants t (k) and t (k + 1) are connected by the relation:
SEP _m (k, t (k)) + SEP _m (k, t (k + 1). (T (fc + 1) - t (k)) = [A _m (t (fc + 1) - h _m (t (k)] +
Vam ² (k, t (k + 1)) - Vam ² (k, t (k)) 2 ^ .5 Method of determining a descent profile and rejoining in minimum thrust of a target point by an aircraft according to any one of claims 3 to 4, in which, for k varying from 1 to N,. * when the adjustable profiles h _m (k, t) and Va _m (k, t) correspond to a phase Φ ( Κ) descent in bounded constant acceleration and in constant and minimum engine speed, the duration At _m (k) of the k-th elementary interval IT (t) and the altitude variation Ah _m (k) over said interval IT (k) check the equations:
... Vam (k, t (k + 1)) - V _am (k, t (k)) ûtm ^- &
and
Δ / ι (fc) = / ^5gP 7n (fc, t (fc)) + SEP _m (k, t (k + E)) _ Vam (t (k) ') + Vam (t (k + 1') ) ₊ _
20 K, _m (t (/ £))). * When the adjustable profiles h _m (k, t) and Va _m (k, t) correspond to a phase 4> (k) of descent at constant CAS or Mach speed and in constant and minimum engine speed, the duration At _m (k) of the k-th elementary interval
25 IT (t) and the altitude variation Ah _m (k) over said interval IT (k) verify the equations
Ah _m (k) = h _m (k, t (k + 1)) - h _m (k, t (k)) and
And _m (k) =
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2 / Vam ² (t (k +1) - Vam ² (t (/ c))
SEP _m (k, tW) + SEP _m (k, t (k + 1)) '[M-mW + 2 ^. * When the adjustable profiles h (k, t) and Va (k, t) correspond to a phase 4> (k) descent in deceleration with constant ER energy ratio and in constant and minimum engine speed, the duration At (k) of the k-th elementary interval IT (t) and the altitude variation Ah (k ) on said interval IT (k) verify the equations:
At _m (k)
2 (Vam ² (t (k + 1) - Vam ² (t (k)) ”ER. (SEP _m (k, t (k)) + SEP _m (k, t (k + 1))) ' 2 ^ and,,. _ (1-ER) (Vam ² (t (k + 1)) - Ram ² (t (k))) ⁾ ~ ER '2g .6 Method of determining a descent profile and of rejoining in minimum thrust of a target point by an aircraft according to any one of the claims
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3 to 5, in which the parametric model of altitude profile h (t) and speed in air goes (t) of the aircraft to be adjusted comprises three successive phases:
a first acceleration / deceleration phase towards a desired CAS speed, then a second phase at the constant desired CAS speed, then .- a third acceleration / deceleration phase towards the final speed,
The desired CAS speed and the durations of the three phases being adjusted so as to satisfy the total duration constraint Lt _{required as} well as the altitude variation constraint duration hi ~ h _f .
.7 Method of determining a descent profile and joining in minimum thrust of a target point by an aircraft according to any one of claims 3 to 5, in which the modeled profile of altitude h (t) and of air speed Va (t) of the aircraft to be adjusted has three successive phases:
a first phase at the initial CAS speed on a first altitude slice Δ / ι (1) with an adjustable duration making it possible to vary an instant of start of deceleration, then a second phase of deceleration from the initial CAS speed to the speed Final CAS, then a third descent phase at final CAS speed to the final altitude,
The altitude variation Δ / ι (1) before deceleration is adjusted iteratively to obtain the duration of the first phase.
.8 Method for determining a descent profile and rejoining in minimum thrust a target point by an aircraft according to any one of claims 1 to 7, in which the third step (6) comprises a first substep (104) during which horizontal departure and arrival positions, P _ai and P _af , within the air mass are determined from horizontal departure and arrival geodesic positions, Pi and Pf , and the horizontal wind speed W _hor (h) assuming that the wind speed and direction depend only on the altitude h and using the relation:
tf_ ₍
W _hor i
and a second sub-step (106) of determining a required lateral distance in the air to be traveled D _a from the speed profile of the aircraft in air Va (t) and the air slope y ( t) using the equation:
rt2 £> a = V _a (t). cos (y (t)) dt
Jti a third sub-step (108) of determining a lateral trajectory in the air Pa (t) joining the horizontal positions of departure and arrival, Pai and Paf and taking into account the vectors of initial speed and
Pai ^p af = final PiPf in air, the length of the lateral trajectory in air Pa (t) being constrained by being set equal to the lateral distance in air required to travel D _a , a fourth sub-step (110) for calculating a geodesic lateral trajectory Pa (t) deduced from lateral trajectory in the air Pa (t) and from the wind map.
.9 Method for determining a descent profile and rejoining in minimum thrust of a target point by an aircraft according to any one of claims 1 to 7, in which the third step (6) comprises a first substep (154) providing a preliminary lateral trajectory of a predetermined type adjustable by modifying a parameter, and a wind model as a function of altitude and possibly of horizontal position and possibly of time, and a second sub -step (156) of adjustment of the at least one parameter of the preliminary lateral trajectory during which the at least one adjustment parameter is modified so that the horizontal geodesic distance traveled along the preliminary lateral trajectory adjusted taking into account the winds ends precisely at the final geodesic position P _f , and a third substep (158) of determining a horizontal geodesic distance requ ise from the profiles of altitude h (t) and speed of the aircraft in the air Va (t), by evaluating at each time t the module | Vg, Aior | the horizontal geodetic speed of the aircraft from the air speed Va (t) and components of the wind speed (XW (t), TW (t)), and integrating over time the module of the horizontal geodetic speed according to the equations:
_r t2 _r t2 _ ^D = fehor | dt = (jV _a ² -XW ² (t) + TW (t)) dt Jti Jtr
XW (t) and TW (t) designating respectively the transverse component and the longitudinal component of the wind at time T, and .10 Method of determining a profile of descent and joining in minimum thrust of a target point by an aircraft according to any one of claims 1 to 9, further comprising a fourth step (10), consecutive to the third step (8), of correcting the profiles of altitude h (t) and speed of the aircraft in the air Va (t), and of the lateral geodesic trajectory, determined respectively in the second and third stages (
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4), (6), which take into account a first effect sft) of the wind gradients in the calculation of the residual energy in the air SEP and / or a second effect s ₂ (t) of the turns on the factor load which modifies the apparent mass in the calculation of the variation of the residual energy in the air SEP (t), the general expression of the residual energy in the air SEP (t) written in the form :
SEP (t) = g
Vg <V dV _a (t) where g denotes the acceleration of gravity near the surface of the Earth.
.11 Method for determining a profile of descent and rejoining in minimum thrust of a target point by an aircraft according to claim 10, in which the fourth step (10) is an iterative process, comprising first, second, third , fourth substep (252, 254, 256, 258) executed in a loop; and
The first sub-step (252), executed initially at the end of the third step (8) and after the fourth sub-step (258) when at least one iteration has been decided during the third sub-step (256) , consists in conventionally determining a temporal evolution of an aircraft state vector including at least the altitude h (t), the speed of the aircraft in the air Va (t), the geodesic distance traveled D (t) along the current geodesic path P (t), initially determined at the start of a first iteration in the third step or determined during the fourth substep of the fourth step, taking into account the wind gradients and the load factor of the turns in the calculation of the change in residual energy SEP (t) until either the final position or the final altitude is reached at a point in the trajectory current geodesic; and the second sub-step (254), executed after the first sub-step (252), consists of the fact that gross deviations ÔD _r , Ô _± , Ôh, δν _α , concerning the geodesic distance traveled, time, l altitude and speed in the air are evaluated between the state of the aircraft, considered at the stopping point and calculated taking into account the correction effects, and the desired final state, and in that deviations refined δΰ _2, Ot ₂ concerning geodesic distance traveled, the time are measured based on gross deviations δΰ _{1, ±} OT, between the state of the aircraft, considered at the breakpoint and calculated by taking into account the effects of correction, and the desired final state, the third substep (256) of testing and of decision to execute an iteration of the loop, executed after the second substep, consists in that the deviations refined OD _2, Ot ₂ traveled geodesic distance and arrival time at the stopping point are compared with a threshold for stopping the output of the loop ε, a connection is made to the fourth substep is made when at least one of the refined deviations δΰ ₂ , δί ₂ is greater than or equal to the stop threshold, and a stop of the fourth step when the two refined deviations δΰ ₂ , Ôt ₂ are strictly below the threshold, the fourth step is completed; and the fourth sub-step (258), executed when at least one refined deviations δΰ ₂ , ot ₂ is greater than or equal to the stopping threshold, consists in that the current profile of altitude h (t) and speed in air Va (t) is readjusted taking into account l refined time difference and reusing the profile adjustment method of the second step, then the lateral trajectory maneuver is readjusted taking into account the refined distance difference and reusing the lateral trajectory adjustment method of the third step to get ning an updated current geodetic trajectory.
.12 Method for determining a descent profile and rejoining in minimum thrust of a target point by an aircraft according to claim 11, in which the refined deviations ÔD ₂ , ôt ₂ of geodesic distance traveled and arrival time at the stopping point are functions of the gross deviations ÔD _± , ôt _± , between the state of the aircraft, considered at the stopping point and calculated by taking into account the correction effects, and the desired final state, according to the relationships :
all ₂ = +
SEP _f and
[5" id="c-fr-0005]
5D ₂ = ÔD ₁ + -. all ₂ . Vf
V _f and SEPf respectively designating the final speed and the variation of residual energy at the stopping point P (iy).
.13 Method for determining a descent profile and joining in minimum thrust of a target point by an aircraft according to one of claims 1 to 12, in which the aircraft is included in all of the airplanes piloted at on board manually or in automatic mode and drones piloted remotely manually or in automatic mode.
.14 System for determining a descent profile and rejoining in minimum thrust of a target point by an aircraft (304), the descent profile permanently in minimum thrust being defined from a first initial state of l initial aircraft until a second final state of the aircraft time constrained by a final arrival time tf or a time delay required ^ required <
the first initial state of the aircraft comprising a first geodetic position Qi of departure, an initial time ti, a first initial altitude hi, a first initial speed of the aircraft VÏ relative to the ground and a first wind speed Wi,
The second final state of the aircraft comprising a second geodesic position Qf of arrival at the target point, a final time tf of constraint, a second final altitude hf, a second final speed of the aircraft ~ Vf relative to the ground and a second wind speed Wf, said determination system comprising a database (306) of the performance of the aircraft (304), a means of supplying meteorological data (308) of the environment in which the aircraft operates (304) , a ground station (310) for supplying the required final time or a time delay required to the aircraft, and one or more electronic computers (312) for calculating the descent and rejoin profile in minimum thrust of a point target, said determination system being configured for in a first step, calculating an energy differential of the aircraft in air ΔΕ _α between the first initial state of the aircraft and the second final state of the aircraft, then in a second step, provide an adjustable model profile of altitude h _m (t) and velocity in air V _am (t) of the aircraft corresponding to a strategy of speed in the air with a constant minimum engine thrust, then adjusting parameters of said adjustable model profile so that the adjusted model profile obtained from altitude h (t) and from air speed Va (t) of the aircraft ensures the consumption of the energy variation of the aircraft in air AE _at within the required time _required , and the required altitude change hi - h _f in the required time with a permanent minimum engine thrust; then in a third step, determine a geodetic trajectory of the aircraft and a lateral geodetic trajectory from a type of lateral maneuver, from the adjusted altitude profile h (t), from the adjusted air speed profile going (t) and knowledge of the wind speeds in the expected geography area of the aircraft crossing.
.15 System for determining a profile of descent and joining in minimum thrust of a target point by an aircraft according to claim 16, in which
The at least one electronic computer (312) for determining a calculation of a descent profile and joining in minimum thrust is .- an electronic computer integrated in a flight management system FMS, an EFB or any computer d 'on-board navigation aid but not integrated into aircraft avionics, .- a computer integrated into an air traffic control ground station, decision support for a controller, a computer integrated into a ground control management station mission of a drone.
.16 System for determining a profile of descent and rejoining in minimum thrust of a target point by an aircraft according to any one of claims 14 to 15, in which .- according to a first configuration, the aircraft comprises a first computer, configured to calculate on board a required intermediate CAS descent speed and a required flight distance, and first transmission means (322) for sending these two requirement parameters, and the air traffic control station comprises second means of transmission (324) to receive the required intermediate CAS descent speed and the required flight distance and send to the aircraft instructions for defining a lateral trajectory and for speed, said instructions being determined by a second computer of the station ground to ensure the required flight distance and intermediate speed, or .- according to a second configuration, the ground station is configured e to send to the aircraft, in addition to the required delay, a point of convergence along the flight plan, and the first computer of the aircraft is configured to determine the intermediate CAS speed and the required geodetic distance, and to identify a point turn, either along a current heading maintenance by a course alignment, or along the current flight plan, by shortening of the trajectory, followed by a direct flight towards the point of convergence.
1/13
Initial airplane state Final stress (Qi, hi, Vi, ti) (Qf, hf, Vf, t _f )

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2018-04-27| PLSC| Search report ready|Effective date: 20180427 |

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2018-09-28| PLFP| Fee payment|Year of fee payment: 3 |

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2019-09-27| PLFP| Fee payment|Year of fee payment: 4 |

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2021-09-30| PLFP| Fee payment|Year of fee payment: 6 |

优先权:

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US15/727,468| US10089893B2|2016-10-20|2017-10-06|Method and system for determining a minimum-thrust synchronous descent and rejoining profile for an aircraft|