• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    System for positioning and orientation in three dimensions of an aircraft (A) with respect to a reference beacon (B) by radio waves, based on the calculation by a Central Processing Unit (CPU) of the delay differences between the signals of input to said Central Processing Unit (CPU). The reference beacon (B) transmits several pseudorandom codes that are detected in the aircraft (A) by correlation with another version of the same codes generated at a slightly different frequency, which causes a slowing effect of the received signal that enables that the Central Processing Unit (CPU) has time to detect it. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2734396A1
    申请号:ES201800132
    申请日:2018-06-05
    公开日:2019-12-05
    发明作者:Gomez Pablo Torio；Sanchez Manuel Garcia；Isasa María Vera
    申请人:Universidade de Vigo；
    IPC主号:
    专利说明:

    [0001]
    [0002] System for positioning and orientation of an aircraft with respect to a reference beacon using radio waves.
    [0003]
    [0004] Technical sector
    [0005]
    [0006] This system finds application in the aviation industry.
    [0007]
    [0008] State of the art
    [0009]
    [0010] At present, there are several systems for aircraft positioning. Among the most widespread is Differential GPS (DGPS) is a technique used for topography and marine navigation based on the use of navigators phase measurements with GPS signals, where a single reference station provides real-time corrections, obtaining great accuracy. Equivalently, this technique can be applied to other satellite positioning systems, such as GLONASS, Galileo and Beidou. The main drawback of this systems is that the GPS is limited to outdoor use since the signal from the satellites hardly reaches interior spaces.
    [0011]
    [0012] Lately, computerized vision positioning systems are being refined that consist of a series of optical sensors coupled to a certain number of image processors that are capable of extracting 3D information from the digital signals captured by the sensors using stereo vision. Based on comparing the information on the scene with respect to reference points, and using the position difference for each one is possible, by triangulation find out the position of the aircraft. However, these systems are complex and, to date, offer limited reliability.
    [0013]
    [0014] Another technique used for positioning is based on the use of laser radars (LIDAR), a remote sensing technology in which the environment is scanned with a pulsed laser beam, to measure the time it takes for the light to return. Although it has some advantages, it has several disadvantages such as the impossibility of measuring in certain types of environments, such as humid atmospheres, areas with vegetation or reflective environments that are very illuminated by the sun. It has a high computational cost and even presents dangers for the human eye in case of direct incidence of the laser.
    [0015]
    [0016] Ultrasonic methods have also been used, as in US2017097645. Ultrasonic methods are based on the delay suffered by sonic waves in the air. This delay, which is typically expressed in microseconds or milliseconds, can be measured by a computer. The reception of ultrasound in aircraft poses serious practical problems due to the vibrations and turbulence caused by the aircraft itself.
    [0017]
    [0018] As an alternative to calculate delay differences, the use of radio waves can be considered. However, radio waves travel at the speed of light and the delays suffered at close distances are of the order of PS that, with current technology, cannot be measured by a computer. The current state of the art does not offer solutions that allow short distances to be measured by a computer using radio waves in aircraft.
    [0019]
    [0020] Explanation of the invention.
    [0021]
    [0022] The present invention consists of a system for positioning and orientation in three dimensions of an Aircraft with respect to a Reference Beacon by means of radio waves, based on the calculation by a Central Processing Unit or CPU of the delay differences between the input signals to the CPU. The present invention overcomes the difficulty offered by the measurement of radio wave delays over close distances, of very short duration, thanks to the use of a pseudorandom code correlation technique that causes a delay effect of said delays.
    [0023]
    [0024] It comprises at least the following elements:
    [0025]
    [0026] - A Reference Beacon, which acts as the issuing entity, which in turn comprises at least the following elements:
    [0027]
    [0028] o An oscillator with IT period.
    [0029]
    [0030] o M pseudorandom code generators.
    [0031]
    [0032] or M radio transmitters.
    [0033]
    [0034] - An Aircraft, which acts as a receiving entity, which in turn comprises at least the following elements:
    [0035]
    [0036] o A Central Processing Unit or CPU.
    [0037]
    [0038] o An oscillator with period T2.
    [0039]
    [0040] or N radio receivers.
    [0041]
    [0042] o N pseudorandom code generators.
    [0043]
    [0044] or N correlators.
    [0045]
    [0046] With the following characteristics:
    [0047]
    [0048] The M number of transmitters and generators of pseudorandom code in the Reference Base is greater than or equal to four. The number N of receivers, pseudorandom code generators and correlators in the Aircraft, is greater than or equal to M, which means that N is also greater than or equal to four. These conditions are necessary to be able to estimate the position and orientation of the Aircraft in the three directions of the space.
    [0049]
    [0050] In the Aircraft, each pseudorandom code generator is linked to a receiver and a correlator.
    [0051]
    [0052] Each of the pseudo-random code generators of the Reference Beacon generates a code identical to that of at least one of the aircraft's generators, which is its twin. The purpose is to identify when a code equal to that linked to each receiver is being received.
    [0053]
    [0054] In the Aircraft, the CPU calculates the position using the delays measured between the signals it receives from the correlators, to which it is connected.
    [0055]
    [0056] The periods TI and T2 of the oscillators differ from each other by a value less than 1% of the lesser of the two, in order to produce a temporary delay in the correlators that allows the CPU to have time to record the delay differences . The reason is that a radio wave has a propagation time that is too short to be detected by a CPU, the present invention comprises a time dilation technique that consists in correlating two pseudorandom codes generated with slightly different periods.
    [0057] The correlation is a mathematical operation between two signals that is implemented as a product followed by an integration of the result over time. It is commonly used to measure the similarity between these two signals.
    [0058]
    [0059] The pseudorandom codes from the issuing entity, when received by each receiver, are correlated with their linked pseudorandom code. The received codes have been generated with T1 chip period. The code linked to the receiver is generated with a T2 chip period, which differs slightly from T1. The generation rate of the transmitted code is defined as f1 = 1 / T1, and the generation rate of the code linked to the receiver is defined as f2 = 1 / T2. It is defined as Af = | f1 - f2 | The difference in rates.
    [0060]
    [0061] When two identical pseudorandom codes generated at slightly different rates are correlated, a time-scaling phenomenon occurs that causes a slowdown effect of the received signal that allows the CPU to have time to detect it. This phenomenon consists in the fact that, since both codes are generated at different rates, one is constantly shifting with respect to the other, so that they are out of date most of the time, except in a brief moment in which both coincide. It is at this moment when the correlation produces a peak of great amplitude that must be registered in the CPU.
    [0062]
    [0063] The Deceleration Factor is defined as k = f1 / Af. The higher k, the greater the time scaling effect and the greater the time the CPU will have to detect the received signals and calculate the delay differences.
    [0064]
    [0065] In a preferred embodiment, all the transmitters of the Reference Beacon are located on a circumference, in the same plane, evenly distributed, so that the same distance between adjacent transmitters is preserved.
    [0066]
    [0067] In a preferred embodiment, all aircraft receivers are located on a circumference, in the same plane, evenly distributed, so that the same distance between adjacent receivers is preserved.
    [0068]
    [0069] These last two characteristics facilitate the correct estimation of propagation delays made in the positioning and orientation procedure. The reason is that, since the Aircraft only has as an estimation tool the signals received from the Reference Beacon, prior knowledge of the spatial arrangement and distance of the transmitters from each other and the receivers from each other is desirable.
    [0070]
    [0071] In one embodiment, the position of the Reference Beacon is fixed relative to a geographical point. In another embodiment, the Reference Beacon is mobile with respect to a geographical point.
    [0072]
    [0073] In one embodiment, the Aircraft uses the calculated position and orientation information to land.
    [0074]
    [0075] In another preferred embodiment, the Aircraft uses the calculated position and orientation information to maintain a fixed position with respect to the Reference Beacon. In this way, the Reference Beacon behaves as a geographical reference for the Aircraft.
    [0076]
    [0077] In one embodiment, the pseudorandom code generators of each entity, sender or receiver, generate different codes.
    [0078] In another preferred embodiment, the pseudorandom code generators of each entity, sender or receiver, generate the same code, but with different lags.
    [0079]
    [0080] In a preferred embodiment, the Reference Beacon or the Aircraft, or both, use an Inertial Measurement Unit to calculate its movement, orientation and inclination. An Inertial Measurement Unit or IMU basically comprises gyroscope and accelerometer and, as a complement, magnetic and barometric sensors.
    [0081]
    [0082] In one embodiment, the positioning and orientation functions are complemented by a global satellite positioning system such as GPS, GLONASS, Galileo, BeiDou, NAVIC, QZSS.
    [0083]
    [0084] In a preferred embodiment, the Aircraft uses all available information, to lead itself to a specific position and orientation.
    [0085]
    [0086] In a preferred embodiment, the CPU is a microcontroller. A microcontroller is a programmable integrated circuit, with inputs and outputs, capable of executing the orders recorded in its memory.
    [0087]
    [0088] Description of the drawings
    [0089]
    [0090] In order to complement the description made, three figures are included as an integral part of said description, where an alternative variant that will be described in the following section is represented by way of illustration and not limitation.
    [0091]
    [0092] Figure 1 represents a system in which the Reference Beacon is named as B and the Aircraft is a quadcopter that is named as A.
    [0093]
    [0094] The transmitters located in the Reference Beacon are named as tx. Each transmitter is accompanied by a graphical representation of three small curved surfaces that indicate radio broadcast.
    [0095]
    [0096] The receivers located on the Aircraft are named as rx.
    [0097]
    [0098] The Reference Beacon (B) has four transmitters: tx 1, tx 2, tx 3 and tx 4, located in the same plane. The Aircraft (A) has four receivers: rx 1, rx 2, rx 3 and rx 4, located in the same plane. Both transmitters and receivers are on a circle that is drawn to emphasize this situation, but that does not necessarily have to exist as a physical element.
    [0099]
    [0100] The spheres TI and T2, which have the symbol above, represent oscillators. The lying cylinders, composed of several adjacent disks, represent generators of pseudorandom code (gene). The lying parallelepids found in the arms of the Aircraft (A) represent corridors (corr). In the center of the Aircraft (A) is a hexahedron that represents the Central Processing Unit (CPU). The electrical connections between all these elements are not expressed graphically, so as not to impair the clarity of the figure.
    [0101] In the center of the Beacon (B) there is an oscillator (TI), which is connected to four pseudorandom code generators (gen 1, gen 2, gen 3 and gen 4), whose codes are emitted by radio through their respective transmitters (tx 1, tx 2, tx 3 and tx 4) to which they are connected.
    [0102]
    [0103] In the center of the Aircraft (A) there is also an oscillator (T2), with a slightly different period than (TI), which is connected to four pseudorandom code generators (gen 1, gene 2, gene 3 and gene 4), identical two to two to the generators (gene 1, gen 2, gen 3 and gene 4) of the Reference Beacon (B).
    [0104]
    [0105] In the Aircraft (A) there are four radio receivers (rx 1, rx 2, rx 3 and rx 4) that receive signal from all transmitters (tx 1, tx 2, tx 3 and tx 4) and deliver it to their linked correlator (run 1, run 2, run 3 and run 4) to which they are connected. The correlators (corr) have their inputs connected to their receiver (rx) and their corresponding generator (gen), and their outputs are connected to the Central Processing Unit (CPU) located in the center of the Aircraft (A).
    [0106]
    [0107] Figure 2 represents a block diagram with the elements of the interconnected issuing entity. There is a single oscillator (T1), which is connected to four pseudorandom code generators (gen 1, gen 2, gen 3 and gen 4), whose codes are emitted by radio through their respective transmitters (tx 1, tx 2, tx 3 and tx 4) to which they are connected. Each transmitter (tx) has an antenna connected, whose emission is represented by small concentric circumference arcs.
    [0108]
    [0109] Figure 3 represents a block diagram with the elements of the interconnected receiving entity. Four radio receivers (rx 1, rx 2, rx 3 and rx 4) are shown that receive signal from their corresponding antenna, whose reception is represented by small concentric circumference arcs. The receivers (rx 1, rx 2, rx 3 and rx 4) deliver the signal to their linked correlators (run 1, run 2, run 3 and run 4). The correlators (corr) have their inputs connected, on the one hand, to their receiver (rx) and, on the other hand, to their corresponding pseudo-random code generator (gen), and their outputs are connected to the Central Processing Unit (CPU) ). All generators (gene) are synchronized by the same oscillator (T2).
    [0110]
    [0111] Detailed description of one embodiment
    [0112]
    [0113] For a better compression, an embodiment is set out in detail that should be understood without limitation of the scope of the invention:
    [0114]
    [0115] The embodiment is described in Figures 1 to 3. It consists of an Aircraft (A), which acts as a receiving entity, and which flies around a Reference Beacon (B), which has the role of a transmitting entity. The Reference Beacon (B) has four equally spaced transmitters (tx), separated by known distances, each of which transmits a different pseudorandom code by radio, provided by its linked generator (gene). These codes are orthogonal to each other, that is, when the correlation is made between them, the result is zero or close to zero while, when the correlation is made between two equal codes, the result is a peak of great amplitude, if both codes coincide in time, which is equivalent to saying that they are not outdated in time. All transmitters (tx) of the Reference Beacon (B) emit their pseudorandom codes linked to the same generation rate, using a common oscillator (T1), with period T1. All these codes are received by all receivers (rx) of the Aircraft (A).
    [0116]
    [0117] In the Aircraft (A) there is an oscillator (T2), with period T2 slightly different from TI, which is common for all code generators (gene). Each receiver (rx) of the Aircraft (A) correlates its pseudorandom code, in its linked correlator (corr), with the signal it receives, thus identifying the moment in which the received signal matches its own code. The Central Processing Unit (CPU) measures the propagation delay differences between the codes identified in each correlator (corr) and calculates from them the position and orientation of the Aircraft (A) with respect to the Reference Beacon (B) .
    权利要求:
    Claims (13)
    [1]
    1. System for positioning and orientation of an Aircraft with respect to a Reference Beacon by means of radio waves comprising at least the following elements:
    - a Reference Beacon (B), which acts as the issuing entity, which in turn comprises at least the following elements:
    or an oscillator (T1) with period T1,
    o M generators of pseudorandom code (gene),
    o M radio transmitters (tx);
    - an Aircraft (A), which acts as a receiving entity, which in turn comprises at least the following elements:
    or a Central Processing Unit (CPU),
    or an oscillator (T2) with period T2,
    or N radio receivers (rx),
    or N pseudorandom code generators (gene),
    or N correlators (corr);
    characterized in that:
    the number M of transmitters (tx) and generators of pseudorandom code (gene) in the Reference Base (B) is greater than or equal to four; the number N of receivers (rx), pseudorandom code generators (gene) and correlators (corr) in the Aircraft (A), is greater than or equal to M; in the Aircraft (A), each pseudorandom code generator (gene) is linked to a receiver (rx) and a correlator (corr);
    each of the generators of the pseudo-random code (gene) of the Reference Beacon (B) generates a code identical to that of at least one of the generators (gene) of the Aircraft (A), which is its twin;
    In the Aircraft (A), the Central Processing Unit (CPU) calculates the position using the delays measured between the signals it receives from the correlators (corr), to which it is connected.
    the periods TI and T2 of the oscillators (TI and T2) differ from each other a value less than 1% of the smaller of the two, in order to produce a temporary delay in the correlators (corr), which allows the Central Processing Unit (CPU) have time to record the delay differences;
    [2]
    2. System according to claim 1, characterized in that all the transmitters (tx) of the Reference Beacon (B) are located on a circumference, in the same plane, evenly distributed, so that the same distance between adjacent transmitters is preserved.
    [3]
    3. System according to any one of claims 1 to 2, characterized in that all receivers (rx) of the Aircraft (A) are located on a circumference, in the same plane, evenly distributed, so that the same distance between adjacent receivers.
    [4]
    4. System according to any of claims 1 to 3, characterized in that the position of the Reference Beacon (B) is fixed with respect to a geographical point.
    [5]
    5. System according to any of claims 1 to 3, characterized in that the Reference Beacon (B) is mobile with respect to a geographical point.
    [6]
    6. System according to any of claims 4 to 5, characterized in that the Aircraft (A) uses the calculated position and orientation information to land.
    [7]
    7. System according to any of claims 4 to 5, characterized in that the Aircraft (A) uses the calculated position and orientation information to maintain a fixed position with respect to the Reference Beacon (B).
    [8]
    System according to any one of claims 6 to 7, characterized in that the generators of pseudo-random code (gene) of each entity, sender or receiver, generate different codes.
    [9]
    9. System according to any of claims 6 to 7, characterized in that the generators of pseudo-random code (gene) of each entity, sender or receiver, generate the same code, but with different lags.
    [10]
    10. System according to any of claims 8 to 9, characterized in that the Reference Beacon (B) or the Aircraft (A), or both, use an Inertial Measurement Unit to calculate its movement and inclination.
    [11]
    11. System according to any of claims 8 to 10, characterized in that the positioning and orientation functions are complemented by a global satellite positioning system.
    [12]
    12. System according to any of claims 8 to 11, characterized in that the Aircraft (A) conducts itself to a specific position and orientation.
    [13]
    13. System according to any of claims 8 to 12, characterized in that the Central Processing Unit (CPU) is a microcontroller.
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    同族专利:
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US6040801A|1964-04-30|2000-03-21|The United States Of America As Represented By The Secretary Of The Navy|Low duty cycle navigation system|
    US6114975A|1996-09-03|2000-09-05|Sextant Avionique|Method of air navigation assistance for guiding a moving vehicle towards a moving target|
    US20160054425A1|2014-08-22|2016-02-25|Daniel A. Katz|Tracking a Radio Beacon from a Moving Device|
    法律状态:
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    申请号 | 申请日 | 专利标题
    ES201800132A|ES2734396B2|2018-06-05|2018-06-05|System for positioning and orientation of an aircraft with respect to a reference beacon using radio waves|ES201800132A| ES2734396B2|2018-06-05|2018-06-05|System for positioning and orientation of an aircraft with respect to a reference beacon using radio waves|
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