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    • 专利摘要:
    Systems and methods are provided for performing alignment calibration of an RF antenna in satellite communications. The received data is representative of inertial navigation system signals and gimbal angle measurements. The received data is collected while a vehicle is operating in a reduced yaw motion and while the RF antenna is tracking a satellite. The equations used describe a mathematical relationship between misalignments, offsets, and latency mismatch with respect to antenna cardan control servocontrol measurements. Estimates are generated for some errors involved in the alignment process. The generated estimates are provided for pointing the RF antenna.
    公开号:FR3062963A1
    申请号:FR1851160
    申请日:2018-02-12
    公开日:2018-08-17
    发明作者:James M. B. Royalty
    申请人:General Dynamics Mission Systems Inc；
    IPC主号:
    专利说明:

    Holder (s): GENERAL DYNAMICS MISSION SYSTEMS, INC ..
    Extension request (s)
    Agent (s): LLR.
    FR 3,062,963 - A1 (54) SYSTEMS AND METHODS FOR INERTIA NAVIGATION SYSTEM FOR RF SIGHT LINE ALIGNMENT CALIBRATION.
    (© Systems and methods are provided for performing an alignment calibration of an RF antenna in satellite communications. The data received is representative of inertial navigation and gimbal angle measurement signals. The data received are collected while a vehicle is actuated in a reduced yaw motion and while the RF antenna is tracking a satellite. The equations used describe a mathematical relationship between misalignments, offsets and latency mismatch with respect to the measurements d antenna gimbal control servo. Estimates are generated for some errors involved in the alignment process. Generated estimates are provided for pointing the RF antenna.
    l
    SYSTEMS AND METHODS FOR INERTIA NAVIGATION SYSTEM FOR RF SIGHTLINE ALIGNMENT CALIBRATION
    CROSS REFERENCE TO THE RELATED APPLICATION The present application claims priority from the provisional American application No. 62 / 458,351 filed on February 13, 2017 and incorporated herein by reference in its entirety.
    TECHNICAL FIELD The technical field relates generally to communication by radio frequency (RF) antenna with satellites and more particularly relates to antenna pointing and pointing alignment calibration.
    BACKGROUND [0003] The antenna systems are subject to alignment for better tracking of the satellites. Antenna calibration is used to align the signal with the peak level of the main beam of the tracking antenna. This provides benefits such as maximum antenna gain. Errors in antenna pointing measurements, however, can cause difficulties in the alignment calibration process.
    [0004] More specifically, terrestrial, aerial and marine satellite communication terminals during movement may require line of sight (LOS) pointing (without tracking) in high precision RF open loop during communications. transmission and reception. This precision maintains a reliable link between the antenna and the satellite by keeping the signal gain high and prevents the antenna terminal from corrupting the communication of adjacent satellites operating in the same frequency band. However, errors in the antenna servo system such as misalignment between the vehicle inertia navigation system (INS) and the antenna can degrade pointing accuracy.
    These errors occur in systems such as satellite communication systems while traveling (Satcom while traveling). Satcom communication while traveling involves a vehicle equipped with a satellite antenna to establish communication with a satellite and maintain that communication while the vehicle is moving. The Satcom antenna application while on the move requires precise pointing, typically without requiring tracking of the satellite signal. Typically, antenna systems are subjected to pointing calibrations to mitigate misalignment and other errors for more precise pointing. These calibrations can be costly in terms of time, materials and labor. The systems and methods described here can significantly reduce the cost of this alignment for large ships and aircraft, but also apply to smaller on-board and terrestrial mobile antenna systems. In addition, the antenna system can use the IMS system of the host vehicle rather than asking the host to provide an additional INS system.
    SUMMARY According to the teachings provided here, non-transient systems, methods, apparatus, computer-readable media for use in data processing devices are provided to perform the alignment calibration of an RF antenna in communications. by satellite. For example, a system is provided to perform an alignment calibration of an RF antenna in satellite communications. Data received is representative of measurement of the inertia navigation system and of gimbal angle signals. The received data is collected while a vehicle performs a reduced yaw movement and the RF antenna tracks a satellite. Equations used describe a mathematical relationship between misalignments, offsets and mismatches, based on latency with respect to the antenna gimbal control servo measurements. Estimates are generated for some errors involved in the alignment process. The estimates generated are provided for pointing the RF antenna.
    Another example: a system based on one or more data processors receives data representative of signals from the inertia navigation system and gimbal angle measurement. The received data is collected while a vehicle performs a reduced yaw movement and the RF antenna tracks a satellite. The equations used describe a mathematical relationship between misalignments, offsets, and latency mismatch with respect to the antenna gimbal control servo measurements. Estimates are generated for alignment angle errors between the inertia navigation system and the antenna gimbal base, antenna gimbal angle measurement offsets and the latency mismatch between the path gimbal angle control and the gimbal angle measurement path. The estimates generated are intended for pointing the RF antenna.
    DESCRIPTION OF THE DRAWINGS Figures 1-3 are block diagrams describing an antenna alignment calibration according to some exemplary embodiments.
    Figure 4 is a block diagram describing physical pointing elements of an open loop RF antenna.
    Figure 5 is a block diagram describing physical pointing elements of RF antenna tracking control.
    Figure 6 depicts a schematic diagram of calibration processing.
    Figures 7 to 9 provide an example of mathematical equations and matrix operations for alignment calibration.
    Figure 10 is a flowchart describing a simulation of antenna alignment calibration.
    DETAILED DESCRIPTION The following detailed description is provided, by its nature, only by way of example and is not intended to limit the demand and its uses. In addition, no connection to any theory expressed or implied is desired, whether it is presented in the previous technical field, the context, the brief summary or the following detailed description.
    Figure 1 depicts at 30 a system 32 for the alignment calibration of an RF antenna 34 in satellite communications, these comprising satellite communications during movement. Satcom products in motion use an inertial navigation system 36 (INS) attached to a vehicle 38 and cardanos with control servo 40 to point the line of sight (LOS) of antenna on a satellite 42.
    An antenna pointing application 44 from Satcom during movement requires precise pointing, without assistance by tracking the satellite signal, for example pointing in open loop, during two-way communication. To assist in antenna pointing, the calibration system 32 receives data from the inertia navigation system and gimbal angle measurements relating to the gimbal servo 40 of the antenna.
    The calibration system 32 performs the calibration while the RF antenna tracks a satellite (reception only) and while the vehicle 38 is actuated in a reduced yaw movement 46. The vehicle 38 is subjected to a yaw movement in order to generate sufficient data for the calibration process. Alignment calibration can be performed with non-planar vehicle movement. Vehicles 48 (e.g. ships, aircraft, etc.) do not have to make multiple revolutions since system 32 performs alignment calibration with reduced vehicle yaw movement. This saves time and money (e.g. labor, materials, etc.). In addition, the system 32 can use the INS system 36 of the host vehicle, thereby reducing the cost of the system.
    On the basis of these data, the calibration system 32 generates estimates 50 of the alignment angle errors between the inertial navigation system 36 and the base of the aerial gimbal, measurement offsets d antenna gimbal angle and latency mismatch between the gimbal angle control path using INS system measurement and the gimbal angle measurement path. The estimates 50 generated are intended for the antenna pointing application 44 in order to point the RF antenna 34. The system alignment calibration can be used during antenna installation or periodic calibration.
    The calibration system 32 takes into account the mechanical misalignments between the INS system 36 and the antenna gimbal base, offsets in the gimbal resolver measurements of azimuth and altitude due to the orientation of the LOS RF line and a difference in the process latency between the INS path and the gimbal angle measurement path. These elements directly degrade the performance of the antenna pointing. If they are not resolved, major errors can occur in this process due to misalignments, offsets and discrepancy in process latency.
    Figure 2 describes in 100 the elements involved in an alignment calibration process. A vehicle 102 hosts an INS system 104 and an antenna 106. More specifically, the INS system 104 provides a heading angle towards the north of the vehicle 102 and angles of step and roll relative to the level. The vehicle's INS 104 system uses a coordinate system based on the latitude, longitude and altitude of the vehicle reference point, to which is added the orientation of the vehicle 102 (roll, pitch and heading).
    The alignment calibration method contributes to aligning the antenna 106 relative to the satellite 108. The angular orientation of the antenna 106 (generally the center line of a paraboloid mirror) is called the line of sight (LOS) of the antenna 106. The LOS line of the antenna is the direction of the maximum RF energy transmitted and received. Before calibration, the LOS RF line may not be aligned with the actual LOS line relative to the satellite 108. The azimuth and antenna altitude gimbals with the resolvers 110 (to send the measurements of the direction of actual antenna pointing), within the framework of the vehicle, determine the antenna coordinate system. More specifically, the resolvers 110 provide measurements of the gimbal angle relative to the vehicle 102.
    FIG. 3 describes the alignment calibration system 32 processing the data entered using mathematical equations describing the relationships 200 between the misalignments, the offsets, and the latency mismatch with respect to the measurements of available antenna gimbal control servo, as illustrated in 202. The resulting 200 relationships provide two equations, but with five unknowns. To find the indeterminate solution, the method acquires measurements on an adequate yaw excursion to obtain sufficient independence for a least squares solution. The iterative least squares solution is configured in this example as follows: performing a first pass of the calibration algorithm; and while the vehicle continues to sinusoidally yaw, using the results of the first pass to improve the results of the second pass, etc. This improves the ability to converge, for angles strongly oriented upwards with a gimbal configuration of internal altitude / external azimuth, towards precise estimates. It should be noted that for an xy gimbal or roll-pitch, the strong upward orientation may not be a problem, but that it can be a problem for the angles of altitude approaching the horizon (high latitudes) and this complication can be resolved by multiple iterations. The tracking mode (for example tracking the RF satellite signal) is used in this method to provide an LOS line of antenna stationary from an angular point of view under a moving vehicle.
    The results include estimates of the two alignment angle errors between the inertial navigation system (INS) and the antenna gimbal base, of the two antenna gimbal angle measurement offsets and latency mismatch between the gimbal angle control path and the gimbal angle measurement path. These values are then used in the open loop pointing solution. This approach induces a significantly reduced vehicle yaw movement to obtain these unknown parameters which can cause significant open-loop pointing errors. This approach moderates the roll and step movement of the vehicle during calibration. These two elements allow airborne and maritime applications (eg small and large craft) for Satcom communications while on the move with far less manpower, materials, and time required during installation.
    FIG. 4 illustrates an alignment calibration method for an open loop pointing using the INS system to measure the orientation of the vehicle towards the north, the angles of pitch and of roll relative to the level. The physical gimbal angles are determined as illustrated in 302 by the difference of the gimbal angle controls and the measured gimbal angles and by the error associated with the angle measurement. The flow 304 through the center of the diagram corresponds to the physical elements of the position of the satellite (or "target") projected, with normalized deviation, in the coordinates of the LOS RF line of the antenna as [1 sy εζ] ’. The second and third elements in the vector represent the pointing errors along the y (yaw or azimuth) and z (step or altitude) axes within the framework of the LOS RF line of the antenna, which causes a loss of gain. satellite communication and related satellite irradiation operating at the same frequency.
    The INS system does not recognize the misalignments between itself and the base of the gimbal. Gimbal resolvers (angle measurement) do not recognize their LOS RF line angle offset from the base of the gimbal. The processor does not recognize the difference in latency between the gimbal angle control and gimbal angle measurement paths.
    FIG. 5 illustrates in 400 that, during tracking, the error vector at the level of the LOS line is brought forcibly to [1 0 0] 'by the tracking control servo loop using the signal RF of the satellite and the tracking receiver as return to bring the gimbals to the angles necessary to maintain the precise pointing. Tracking the satellite signal is a receive method only and is allowed during this calibration. But during bidirectional communications, the absence of tracking is required due to the greater pointing error during tracking, which is why the pointing of the LOS line of the antenna on the satellite must be carried out in open loop mode. (no RF signal return).
    During calibration during tracking of the satellite signal, the gimbal angles are defined so as to maintain the LOS RF line on the satellite during tracking independent of the INS system (gimbal control) and angle measurements. gimbal. The difference between the gimbal control and the gimbal angle measurements during the chase represents the imprecision of the pointing control in open loop since these two measurements are used to control the position of the LOS RF line as can be see it in figure 5. It is then possible to develop equations compensating for the difference between the gimbal commands (INS system path) and the gimbal measurements during the chase.
    The azimuth (heading north) and altitude of the satellite ("target") angles are again described as a vector [xyz] 'in the local level reference frame. This satellite vector, transformed by the vehicle's orientation towards the north and the level, is now described in the vehicle reference frame (forward - x, starboard - y and down - z). This vector is converted into azimuth and altitude commands by the arctan (y / z) and arctan (-z / sqrt (x A 2 + y A 2)), respectively. This initial process is included in the software and in the analysis model used to verify the algorithm. These commands are not aware of any misalignments of the INS system relative to the base of the gimbal.
    The satellite vector in the coordinates of the vehicle is transformed with misalignments of the unknown INS system (unknown to the software, but known from the analysis of reports of estimated errors) relative to the base of the gimbal and whatever the gimbal position angles required to maintain the satellite vector at [1 0 0] 'as part of the LOS RF line of the antenna. Offsets are added to the azimuth gimbal position and altitude measurement. In some situations, the INS system yaw misalignment relative to the gimbal base and the azimuth gimbal measurement offset are added to form an error and placed in the previous INS system's misalignment transformation during analysis.
    The equations for the gimbal controls and the gimbal angles which involve the gimbal controls, the misalignments and the gimbal angle measurements are differentiated to produce extensive equations. These equations relate error measurements to misalignment and offset errors.
    FIG. 6 illustrates at 500 a principle diagram of the calibration processing. As illustrated in 502 in the figure, we are witnessing an acquisition of the inputs coming from the vehicle GPS, from the satellite GPS, from the INS system and from the resolvers. The mean angles of the INS system and the mean angles of the gimbal are calculated. As illustrated in 504, the mean angles of the INS system and the mean angles of the local level of the satellite are subjected to a transformation process also taking into account misalignments and latency. As shown in 506, matrix operations are performed when creating the system model so that a least squares formula can calculate estimates for misalignment, offset and latency. Figures 7 and 8 show an example of mathematical equations and matrix operations for alignment calibration.
    FIG. 7 illustrates at 600 two equations representing the azimuth and altitude errors where the terms in red font are the unknown misalignments (pitch delta and roll delta and gimbal measurement offsets). The azimuth misalignment delta has been added to the azimuth gimbal offset to facilitate the equation formula without loss of precision. The Greek letters with a bar above correspond to the measurements. The left side of the equations corresponds to the position error: gimbal control minus gimbal angle measurement.
    The two equations of FIG. 7 can be transformed into space of states as illustrated at 700 in FIG. 8. The equations of space of states can be represented in linear or matrix algebraic form as shown in the figure 8 where the upper line of the matrix is multiplied by the vector, element by element, so that the sums are equal to the right side. These two equations can be represented by Ax = y, where "A" is the coefficient matrix, "x" contains the unknowns being estimated and the error measures are the vector "y".
    As illustrated at 800 in Figure 9, when more measurements (i.e., first measurement, second measurement, third measurement, etc.) are taken, the measurements are added to the matrix A and to the vector y. The 1st column of the matrix A alternates between 1 and 0, the 2nd column alternates between 0 and 1 and the 3 rd , 4 th and 5 th columns are repeated two rows by two with sequential measurement formulas. The matrix A will then have a number of lines 2 * N by five (number of estimated error terms) columns wide. And the vector will have a number of lines 2 * N, where N is the number of measures. When the vehicle pitch and roll inputs are included in the whole algorithm, the matrix A changes, but the vectors x and y remain identical.
    Typically, in linear algebra, to solve x, the two sides of the equation are multiplied by A-l if A is invertible. But since A is not square (unequal number of rows and columns), it is not invertible. We first multiply the two sides by A transposed, At, which produces a square matrix. Then we multiply the two sides by the inverse, (AtA) -l, which makes it possible to find x, x = (AtA) -lAt y, which is calculated in real time on the basis of low sample speed. AtA is a matrix of 5 rows by 5 columns depending on the number of estimated unknown terms and not depending on the number of measurements. In addition, the product of At y remains a vector of 5 rows by 1 column regardless of the number of measurements. Thus, rather than keeping A and y which continue to grow with each measurement, we keep (AtA) -l and At y which remain the same size throughout the measurement process.
    For example, the solution may include a formula for the best estimate of the unknowns, x. This is called a least squares formula. This equation creates valid results in the presence of sufficient vehicle yaw displacement. Otherwise, almost the same equation continues to feed the matrix A and no new information is added so that the resulting situation with two equations with five unknowns continues to exist in practice.
    As shown in Figure 10, a Monte Carlo 900 simulation can be used to determine the minimum vehicle movement required and the maximum satellite angles at altitude to provide an adequate estimate of errors for a 2-axis gimbal configuration particular as illustrated in 902. In 904, four of the five unknowns were randomized to be distributed uniformly as part of the manufacturing requirements. In 906, the latency was fixed as expected between identical models produced. The vehicle's yaw, pitch and roll amplitudes and frequencies were fixed, but their phasing in relation to each other was made random. The initial heading of the vehicle was made random relative to the heading of the satellite. The altitude angle relative to the satellite was set at various altitude angles to understand this dependence.
    The algorithm is executed while the vehicle is moving and performs cyclical yawning maneuvers between ± 10 and ± 45 degrees. As the vehicle continues to move, the algorithm is executed 2nd time using the results of the era going to improve the outcome of the 2 nd pass. This is repeated until the azimuth and altitude gimbal errors (angle control - angle measurement) are below a threshold during a pass. The threshold is defined according to the conceivable possibility of system pointing errors which can range from 0.02 to 0.15 degrees depending on the needs of the application. This threshold is typically reached between 3 and 6 passes. Each pass has a duration fixed at 10 (TBR) seconds. Data is collected at the speed of the loop sample in position. Every 0.1 (TBR) seconds, the algorithm is run once to estimate the unknown parameters. Each pass thus has 10 / (0.1) or 100 measurements to create the 908 estimates for misalignment error, measurement offset and process latency.
    An example may include angles oriented upwards of 75 degrees (worst case of upward orientation close to the equator) relative to the satellite with 5 degrees of step movement and roll of the vehicle and only ± 15 degrees of yaw movement of the vehicle. The algorithm estimates the misalignment, offset and latency so that the control angle errors minus the gimbal angle for an entire yaw revolution are less than an error of 0.015 in 3 to 7 passes ( each pass for 10 seconds).
    With the upward orientation relative to the satellite at 49 degrees, the position error continues to be less than 0.015 degrees for an entire revolution with just 3 and 4 passes. With an upward orientation relative to the satellite at 63 degrees, the number of passes is between 3 and 5. The algorithm takes between 3 and 8 passes when the vehicle's pitch and roll are increased to 15 degrees.
    The parameter estimates are formulated for a limited vehicle yaw movement. The analysis thus calculates the pointing error while the vehicle crosses 360 degrees of yaw movement to verify that the algorithm continues to be precise on any excursion of the vehicle yaw angle. The peak error is typically significantly less than 0.03 degrees for a possibility of a total pointing error of 0.2 degrees. This error limit is defined by the threshold in the algorithm. If less precision is required, fewer iterations are needed and less time.
    Even if at least one exemplary embodiment has been presented in the preceding detailed description, it should be noted that a very large number of variations exist. It should also be noted that the embodiment or embodiments are only examples and are not intended to limit the scope, applicability or configuration of the invention in any way. The preceding detailed description rather provides those with average skills in the field with a suitable roadmap for implementing the embodiment or the embodiments given by way of example. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the invention as set out in the appended claims and in the corresponding legal equivalents. As an example of the possible wide variations of the systems and methods described herein, a system can be configured to operate with undulating vehicle movement even with moderate vehicle pitch and roll, a target altitude of up to 75 degrees and a configuration of internal altitude / external azimuth gimbal. The system may prove beneficial in environments such as marine and aircraft applications where calibration may require considerably more time, materials, and labor than on trucks, even if the The present invention remains applicable to land vehicles.
    By way of illustration, a system can be configured to perform a calibration requiring between 10 to 45 degrees of vehicle yaw movement. As mentioned above, it is an advantage for marine and airborne applications to reduce costs in terms of time, labor, and materials. The system can allow up to at least 15 degrees of roll and pitch at lower satellite altitude angles (up to 65 degrees) and up to 5 degrees for satellites approaching 75 degrees for the gimbal configuration. indoor altitude / outdoor azimuth. On the contrary, the previous alignment calibration systems, carried out during the positioning of the vehicle and then periodically, constrain the vehicle on which the Satcom communication antenna being
    The antenna movement is fixed to perform up to two yaw revolutions. In addition, these previous systems require a yaw movement near the horizontal plane. In other words, such an alignment process requires 1-2 full yaw revolutions of the vehicle and almost planar movement to be precise and the vehicle to be stationary for the other error estimation.
    Current approaches can also involve intensive operations, such as the following two-step process. The first step involves IMU Alignment with Altitude Shift and INS treatment on the basic gait and roll delta. More specifically for the first stage, the vehicle is driven in a circle on a parking lot while continuing the satellite signal. The El gimbal control state is compared to the altitude resolver. The gimbal command El derived from Satellite az and el at local level is converted into vector X, Y, Z, transformed in the framework of the vehicle by the heading, step and roll INS and the function atan2. The error between the Command and the resolver is treated. For the offset, the average of the vehicle's 360 degree travel error is obtained. The INS misalignment on the base of the gimbal for the pitch is demodulated by the cosine (INS cap-vehicle cap) and an average over 360 degrees of the vehicle's yaw travel is achieved. The INS misalignment on the gimbal base for the Roll is demodulated by the sinus (INS course + vehicle course) and an average over 360 degrees of the vehicle's yaw travel. The offset is applied to the resolver measurement with the step and roll delta incorporated in a revised gimbal control development.
    The second step involves IMU alignment with azimuth offset. More specifically for the second stage, while the vehicle is stationary, the gimbals are controlled to point the LOS RF line at the Satellite level and record the mean azimuth resolver angle. The mode is changed to tracking (LOS RF line culminating in the satellite signal) and again records the average azimuth resolver angle. Azimuth angles are subtracted and applied to the azimuth resolver measurement as an offset.
    The system can be configured with the operations described here to replace the operations such as steps 1 and 2 and others. This allows for more efficient processing, for example by reducing the amount of yaw movement of the vehicle so that vehicles (e.g. ships, aircraft, trucks, etc.) do not need to make multiple revolutions, thus saving time and money (for example in the form of labor and materials). The process also applies during installation of the antenna or during periodic calibration.
    As another example of significant variations of the systems and methods exposed here, the systems and methods may require, for a gimbal configuration of interior altitude / exterior azimuth and for significant LOS line altitude angles, for example at - above 70 degrees (for operations near the equator), a compromise between the amount of vehicle yaw movement required and the vehicle's step and roll movement allowed. The greater the angle of altitude, the greater the amount of yaw movement of the vehicle required and the lower the authorized pitch and roll of the vehicle due to the amount of gimbal movement (outside) of azimuth necessary for maintain the pursuit. For altitude angles below a certain amount (e.g. 63 degrees), the amount of vehicle yaw movement can approach +/- 10 degrees. In some situations, the vehicle yaw motion can be 0.01 degrees and the unknowns can be estimated with very little error.
    As another example of significant variations, the system can be configured to allow the use of the INS system of the host vehicle, thereby significantly reducing the cost of providing the system.
    Yet another example among the significant variations of the systems and methods exposed here, it should be understood that the steps and the order of the steps in the processing flows described here can be changed, modified, withdrawn and / or increased while continuing to achieve the desired result. By way of illustration, a multiprocessing or multitasking environment could allow two or more steps to be executed simultaneously.
    In addition, data from systems and processes (e.g. associations, mappings, data inputs, data outputs, intermediate data results, final data results, etc.) can be stored and implemented in a or several different types of data stores implemented on the computer, such as different types of storage devices (eg memory) and programming constructs (eg RAM, ROM, Flash memory, flat files, databases, data structures programming data, programming variables, affirmation constructs of type SI-THEN (or similar type, etc.). Note that the data structures describe formats to be used in the organization and storage of data in databases, programs, memories or other computer-readable media intended for use by a computer program.
    In addition, systems and methods can be provided on many different types of computer-readable memory media including computer storage mechanisms (for example non-transient media, such as CD-ROMs, floppy disks, RAM, flash memory, computer hard drives, etc.) containing instructions (for example software) intended to be executed by a processor to perform process operations and implement the systems described here.
    权利要求:
    Claims (20)
    [1" id="c-fr-0001]
    1. Method for the alignment calibration of an RF antenna in satellite communications, comprising:
    reception, using one or more data processors, of data representative of inertial navigation system and gimbal angle measurement signals;
    wherein the received data is collected while a vehicle is operated in a reduced yaw motion and while the RF antenna is tracking a satellite;
    the use, by the data processor (s), of equations describing a mathematical relationship between the misalignments, the offsets and the discrepancy of latency with respect to the servo-control measurements of antenna gimbal control;
    generation of estimates by the data processor (s) of alignment angle errors between the inertia navigation system and the aerial gimbal base, antenna gimbal angle measurement offsets , and the latency mismatch between the gimbal angle control path and the gimbal angle measurement path based on the equations;
    in which the estimates generated are intended for pointing the RF antenna.
    [2" id="c-fr-0002]
    2. Method according to claim 1, in which the estimates generated are provided for an open loop pointing solution for the RF antenna.
    [3" id="c-fr-0003]
    3. The method of claim 1, wherein a first pass using the equations is performed for the calibration algorithm;
    wherein, while the vehicle is sinusoidally yawning, the results of the first pass are used to improve the results of the second pass for the iterative calibration solution.
    [4" id="c-fr-0004]
    4. The method of claim 3, wherein the use of the results of the first pass improves the ability to converge for strongly upward angles with gimbal configuration of indoor altitude / outside azimuth.
    [5" id="c-fr-0005]
    5. Method according to claim 3, in which the iterative solution of the equations results in a reduction of the yaw movement of the vehicle necessary to obtain the estimates.
    [6" id="c-fr-0006]
    6. Method according to claim 5, in which the yaw displacement of plus or minus 0.01 degrees is used for the iterative solution of the equations.
    [7" id="c-fr-0007]
    7. The method of claim 5, wherein the yaw displacement of plus or minus 10 degrees is used for the iterative solution of the equations.
    [8" id="c-fr-0008]
    8. The method of claim 3, wherein the iterative solution of the equations is repeated until the gimbal errors of azimuth and altitude do not exceed a predetermined threshold during a pass.
    [9" id="c-fr-0009]
    9. The method of claim 8, wherein the predetermined threshold is defined according to the possible possibility of pointing errors of the system.
    [10" id="c-fr-0010]
    10. The method of claim 9, wherein the possible range of possible pointing errors of the system is between 0.02 and 0.15 degrees depending on the needs of the application.
    [11" id="c-fr-0011]
    11. The method as claimed in claim 3, in which the iterative solution of the equations results in a reduction in the roll and pitch movement of the vehicle during calibration.
    [12" id="c-fr-0012]
    12. The method of claim 3, wherein the iterative solution of the equations results in a reduction in the estimates of pointing errors in open loop.
    [13" id="c-fr-0013]
    13. The method of claim 3, wherein the approach involving a sinusoidal movement results in pointing the RF antenna with a reduction in labor, materials and time required during installation.
    [14" id="c-fr-0014]
    14. The method of claim 3, wherein the least squares approach performs the iterative solution of the equations.
    [15" id="c-fr-0015]
    15. The method of claim 3, wherein a stochastic statistical simulation validates the iterative solution of the equations.
    [16" id="c-fr-0016]
    16. The method of claim 1, wherein a tracking mode is used during the calibration algorithm and provides an LOS line of stationary antenna angularly under the moving vehicle.
    [17" id="c-fr-0017]
    17. The method of claim 1, wherein the calibration algorithm is used for the alignment calibration of an RF antenna with a celestial object which is stationary during the test, wherein the celestial object is a star or a moon.
    [18" id="c-fr-0018]
    18. The method of claim 1, wherein the calibration algorithm uses the host inertia navigation system; in which the vehicle is a truck, van, aircraft or ship.
    [19" id="c-fr-0019]
    19. System for performing the alignment calibration of an RF antenna in satellite communications, said system comprising:
    a memory device for memorizing instructions for performing the alignment calibration; and one or more data processors configured to execute the instructions for:
    receive data representative of inertial navigation system and gimbal angle measurement signals;
    wherein the received data is collected while a vehicle is operated in a reduced yaw motion and while the RF antenna is tracking a satellite;
    use equations describing a mathematical relationship between misalignments, offsets and latency mismatch with respect to the antenna gimbal control servo measurements;
    generate estimates of alignment angle errors between the inertia navigation system and the aerial gimbal base, antenna gimbal angle measurement offsets and latency mismatch between the control path gimbal angle and the gimbal angle measurement path;
    in which the estimates generated are intended to point to the RF antenna.
    [20" id="c-fr-0020]
    20. Non-transient computer readable medium on which are stored instructions for performing the alignment calibration of an RF antenna in satellite communications which, when executed, bring one or more
    5 processors to:
    receive data representative of inertia navigation and gimbal angle measurement signals;
    wherein the received data is collected while a vehicle is operated in a reduced yaw motion and while the RF antenna is tracking a satellite;
    10 use quations describing a mathematical relationship between the misalignments, the offsets and the discrepancy in latency with respect to the antenna gimbal control command measurements;
    generate estimates of alignment angle errors between the inertia navigation system and the aerial gimbal base, angle measurement shifts of
    15 antenna gimbal and latency mismatch between the gimbal angle control path and the gimbal angle measurement path;
    in which the estimates generated are intended to point to the RF antenna.
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    同族专利:
    公开号 | 公开日
    TR201801964A2|2018-08-27|
    US10756428B2|2020-08-25|
    ZA201800897B|2019-01-30|
    AU2018200878A1|2018-08-30|
    US20180233819A1|2018-08-16|
    FR3062963B1|2019-11-22|
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    法律状态:
    2019-02-25| PLFP| Fee payment|Year of fee payment: 2 |
    2020-02-25| PLFP| Fee payment|Year of fee payment: 3 |
    2021-02-23| PLFP| Fee payment|Year of fee payment: 4 |
    2022-02-23| PLFP| Fee payment|Year of fee payment: 5 |
    优先权:
    申请号 | 申请日 | 专利标题
    US201762458351P| true| 2017-02-13|2017-02-13|
    US62458351|2017-02-13|
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