Unmanned aerial vehicle tracking angle measurement phase zero calibration device and method

Abstract

The invention discloses an unmanned aerial vehicle tracking angle measurement phase zero calibration device and method, and particularly relates to the field of unmanned aerial vehicle measurement and control, and the method comprises the steps: before an unmanned aerial vehicle takes off, a monitor sends servo control data to a servo controller, and adjusts the focal length of an image collector, and the servo controller controls a servo turntable to rotate to adjust the angle of a directional antenna; the unmanned aerial vehicle is located in the view center of the image collector; the ground terminal determines an initial phase difference and an initial deflection angle of the two receiving channels according to the telemetering radio frequency signals received by the two receiving channels; after the unmanned aerial vehicle takes off, the ground terminal determines the real-time phase difference and the real-time deflection angle of the two receiving channels, determines the required deflection angle of the directional antenna according to the real-time deflection angle and the real-time deflection angle, and sends the required deflection angle of the directional antenna to the servo controller, and the servo controller controls the directional antenna to be aligned with the unmanned aerial vehicle. And accurate phase zero calibration can be ensured.

Description

Technical Field

[0001] The present application relates to the field of unmanned aerial vehicle measurement and control, and in particular to a device and method for zeroing phase of unmanned aerial vehicle tracking, angle measurement, and so on. Background Art

[0002] In the UAV data link measurement and control system, the ground measurement and control station commonly uses two tracking methods for UAVs: automatic tracking and GPS / Beidou guidance. Among the automatic tracking methods, the phase angle measurement scheme is widely used because of its high measurement accuracy and high reliability. In an ideal situation, when the directional antenna of the ground measurement and control station is aimed at the UAV, the two receiving channels of the ground data terminal receive the same phase of the RF signal emitted by the omnidirectional antenna on the UAV, and the angle of the UAV deviating from the normal direction of the ground directional antenna is calculated to be zero. However, in actual applications, due to the asymmetry of the antenna array elements, the inconsistency of the RF cable length, and the inconsistency of the RF signal wiring length of the circuit board, the signal paths of the two receiving channels of the ground data terminal are not the same length, and there is always a phase difference, so the angle of the UAV deviating from the normal direction of the directional antenna is not zero, which affects the performance indicators of the UAV data link, such as the measurement and control distance and bit error rate. Therefore, in order to make the performance indicators of the UAV data link better, it is necessary to ensure that when the directional antenna of the ground measurement and control station is aimed at the UAV, the phase difference of the two receiving channel signals of the ground data terminal is also consistent. Existing solutions include: adjusting the position of the antenna element to make it symmetrical; adjusting the length of the two receiving channel cables to eliminate the carrier phase difference caused by the cable length difference; adjusting the layout of the RF signal on the circuit board to eliminate the phase difference caused by the RF signal layout; using a 3-channel antenna and using one of them for the calibration channel. The first three methods require a lot of time and manpower and material resources, and still cannot completely eliminate the phase difference. The fourth method requires increasing the antenna size and the number of array elements, which increases the cost. Summary of the invention

[0003] The main purpose of the present application is to provide a phase zeroing device and method for UAV tracking and angle measurement, aiming to solve the problem that the existing phase zeroing method cannot completely eliminate the phase difference.

[0004] To achieve the above-mentioned purpose, the present application provides a UAV tracking angle measurement phase zeroing device, including: a servo turntable; a directional antenna fixed on the servo turntable, the directional antenna is used to receive telemetry radio frequency signals; connected to a ground terminal via a radio frequency cable; a ground terminal connected to the directional antenna, the ground terminal is used to process the telemetry radio frequency signals received by the directional antenna to obtain telemetry data; an image collector is arranged on the directional antenna, the image collector is used to collect images of the UAV; a monitor is connected to the image collector, used to adjust the focal length of the image collector, and display the UAV images collected by the image collector, the monitor is also connected to the ground terminal, and is used to determine servo control data based on the telemetry data; a servo controller is connected to the servo turntable and the monitor, and is used to rotate the servo turntable according to the servo control data.

[0005] Optionally, the directional antenna is a dual-channel antenna.

[0006] Optionally, the ground terminal includes: a frequency conversion sampler connected to the directional antenna, the frequency conversion sampler is used to convert the frequency and sample the telemetry radio frequency signal received by the directional antenna; a data processor connected to the frequency conversion sampler and the monitor, the data processor is used to process the frequency converted and sampled signal to obtain telemetry data, and send the telemetry data to the monitor; a shell, the frequency conversion sampler and the data processor are located inside the shell.

[0007] Optionally, two radio frequency ports are provided on the shell, and two radio frequency channel interfaces of the directional antenna are respectively connected to the two radio frequency ports through radio frequency cables.

[0008] Optionally, the frequency conversion sampler is an AD9361 radio frequency chip.

[0009] Optionally, the data processor is a ZYNQ7100 chip.

[0010] To achieve the above-mentioned purpose, the present application also provides a method for zeroing the phase of an unmanned aerial vehicle tracking angle measurement, which adopts the above-mentioned zeroing device, including: before the unmanned aerial vehicle takes off, the monitor sends servo control data to the servo controller and adjusts the focal length of the image collector, and the servo controller controls the servo turntable to rotate and adjust the angle of the directional antenna so that the unmanned aerial vehicle is located at the center of the field of view of the image collector; the ground terminal determines the initial phase difference of the two receiving channels according to the telemetry radio frequency signals received by the two receiving channels, and determines the initial deflection angle of the directional antenna according to the initial phase difference; after the unmanned aerial vehicle takes off, the ground terminal determines the real-time phase difference of the two receiving channels according to the telemetry radio frequency signals received by the two receiving channels, determines the real-time deflection angle of the directional antenna according to the real-time phase difference, and determines the desired deflection angle of the directional antenna according to the real-time deflection angle and the real-time deflection angle, and sends the desired deflection angle of the directional antenna to the monitor; the monitor sends the desired deflection angle of the directional antenna to the servo controller, and the servo controller controls the servo turntable to rotate so that the directional antenna is aimed at the unmanned aerial vehicle.

[0011] Optionally, the phase difference is calculated as:

[0012] In the formula, Q A , Q B are the orthogonal components of the signals of the two receiving channels, I A ,I B are the in-phase components of the signals of the two receiving channels respectively.

[0013] Optionally, the calculation formula for the deflection angle is:

[0014] Where λ is the wavelength, D is the distance between two array elements, is the phase difference.

[0015] Optionally, the calculation formula for the deflection angle is:

[0016] In the formula, θ 实 is the real-time deflection angle, and θ0 is the initial deflection angle.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The phase zeroing device for tracking and measuring angles of unmanned aerial vehicles of the present invention adjusts the angle of the directional antenna and the focal length of the image collector by a servo turntable before the unmanned aerial vehicle takes off, so that the directional antenna is aligned with the unmanned aerial vehicle, and the accuracy of the initial phase difference is ensured, thereby ensuring the phase zeroing during the tracking process; a dual-channel antenna is adopted, and the angle of the directional antenna is adjusted by rotating the servo turntable to make the phase difference of the dual channels consistent, so as to achieve the phase zeroing of tracking and measuring angles of unmanned aerial vehicles. Compared with adjusting the symmetry of antenna array elements, adjusting the cable length, and wiring of radio frequency signals on circuit boards, the adjustment time is reduced and the accuracy of zeroing is increased.

[0018] The phase zeroing method for tracking and measuring angles of an unmanned aerial vehicle of the present invention uses a monitor and an image collector to align a directional antenna with the unmanned aerial vehicle before the unmanned aerial vehicle takes off, and calculates the initial phase difference of the directional antenna to further ensure accurate phase zeroing; after the unmanned aerial vehicle takes off, the phase difference of the directional antenna is calculated in real time to determine the deflection angle, and the angle of the directional antenna is adjusted by a servo turntable to achieve alignment, which can save zeroing time, increase the accuracy of zeroing, reduce manpower, and does not need to increase the size of the antenna and the number of channels. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of a UAV tracking angle measurement phase zeroing device for this application; Figure 2This is a schematic diagram of the calculation principle of the UAV deviation angle in a UAV tracking angle measurement phase zeroing method in this application; The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of this application clearer, the technical solutions in this application will be clearly and completely described below in conjunction with the drawings in this application. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0021] The first embodiment of the present invention provides a UAV tracking angle measurement phase zeroing device, such as Figure 1 As shown, it includes a servo turntable 10, a directional antenna 20, a ground terminal 30, an image collector 40, a monitor 50 and a servo controller 60. The directional antenna 20 is fixed on the servo turntable 10. The directional antenna 20 can be a channel antenna and is used to receive telemetry radio frequency signals; it is connected to the ground terminal 30 through a radio frequency cable; the ground terminal 30 is connected to the directional antenna 20, and the ground terminal 30 is used to process the telemetry radio frequency signals received by the directional antenna 20 to obtain telemetry data; the image collector 40 is set on the directional antenna 20; the monitor 50 is connected to the image collector 40, and is used to adjust the focal length of the image collector 40 and display the picture of the image collector 40. The monitor 50 is also connected to the ground terminal 30, and is used to determine the servo control data according to the telemetry data; the servo controller 60 is connected to the servo turntable 10 and the monitor 50, and is used to rotate the servo turntable 10 according to the servo control data.

[0022] Specifically, the image collector 40 can be a camera, and the ground terminal 30 includes a frequency conversion sampler 31, a data processor 32 and a housing 33. The frequency conversion sampler 31 is connected to the directional antenna 20, and the frequency conversion sampler 31 is used to convert and sample the telemetry radio frequency signal received by the directional antenna 20; the data processor 32 is connected to the frequency conversion sampler 31 and the monitor 50, and the data processor 32 is used to process the frequency conversion and sampled signal to obtain telemetry data, and send the telemetry data to the monitor 50; the housing 33, the frequency conversion sampler 31 and the data processor 32 are located in the housing 33. Exemplarily, the frequency conversion sampler 31 is an AD9361 radio frequency chip. The data processor 32 is a ZYNQ7100 chip.

[0023] Furthermore, two RF ports, ie, RF port A and RF port B, are provided on the shell 33, and two RF interfaces (RF port C and RF port D) of the directional antenna 20 are respectively connected to the two RF ports through RF cables.

[0024] In this embodiment, a dual-channel antenna is used, and the angle of the directional antenna 20 is adjusted by rotating the servo turntable 10 to eliminate the phase difference of the dual channels, so that the directional antenna 20 is aimed at the drone, and the phase zeroing of the drone tracking angle measurement is achieved. Compared with adjusting the symmetry of the antenna array elements, adjusting the cable length, and wiring the RF signal on the circuit board, the adjustment time is reduced; before the drone takes off, the angle of the directional antenna 20 and the focal length of the image collector 40 are adjusted by the servo turntable 10 to achieve the alignment of the directional antenna 20 with the drone, thereby ensuring the accuracy of the initial phase difference, thereby ensuring the phase zeroing during the tracking process.

[0025] A second embodiment of the present invention provides a method for zeroing an angle measurement phase of an unmanned aerial vehicle tracking, comprising the following steps: Step S1, before the drone takes off, the monitor 50 sends servo control data to the servo controller 60 and adjusts the focal length of the image collector 40. The servo controller 60 controls the servo turntable 10 to rotate and adjust the angle of the directional antenna 20 so that the drone is located at the center of the field of view of the image collector 40; Specifically, the monitor 50 can be a computer, on which servo control software and flight monitoring software are installed. Before the drone takes off, the servo control data is manually input into the servo control software, and the servo controller 60 receives the servo control data, thereby controlling the rotation of the servo turntable 10, and then rotating the directional antenna 20, until the drone enters the field of view of the image collector 40, at which time the preliminary alignment is completed; then, the drone is manually operated on the flight monitoring software to adjust the focal length of the image collector 40 so that the drone is located at the center of the field of view of the image collector 40, and the drone image occupies more than 1 / 3 of the entire image, completing the precise alignment of the drone. When the monitor 50 sends the servo control data to the servo controller 60, the servo controller 60 will return its own servo status data to the monitor 50.

[0026] After the alignment is completed, calibration begins. The start of calibration can be indicated by the monitor 50 sending a calibration instruction in the form of a remote control data frame to the ground terminal 30. After the ground terminal 30 receives the calibration instruction, it calculates the initial phase difference of the two receiving channel signals of the ground terminal 30, as follows.

[0027] Step S2, the ground terminal 30 determines the initial phase difference between the two receiving channels according to the telemetry radio frequency signals received by the two receiving channels, stores the initial phase difference, and determines the initial deflection angle of the directional antenna 20 according to the initial phase difference; The calculation formula of the initial phase difference is:

[0028] In the formula, Q A , Q Bare the orthogonal components of the signals of the two receiving channels, I A ,I B are the in-phase components of the signals of the two receiving channels respectively; Combination Figure 2 It can be obtained that the calculation formula for the initial deflection angle is:

[0029] Where λ is the wavelength and D is the distance between two array elements.

[0030] After obtaining the initial deflection angle, the UAV takes off and is tracked. Specifically, the monitor 50 may send a tracking instruction in the form of a remote control data frame to the ground terminal 30, and the ground terminal 30 performs real-time tracking, as follows.

[0031] Step S3, after the drone takes off, the ground terminal 30 determines the real-time phase difference between the two receiving channels according to the telemetry radio frequency signals received by the two receiving channels, determines the real-time deflection angle of the directional antenna 20 according to the real-time phase difference, determines the required deflection angle of the directional antenna 20 according to the real-time deflection angle and the real-time deflection angle, and sends the required deflection angle of the directional antenna 20 to the monitor 50; The calculation formula of phase difference is:

[0032] In the formula, Q A , Q B are the orthogonal components of the signals of the two receiving channels, I A ,I B are the in-phase components of the signals of the two receiving channels respectively; The calculation formula for the deflection angle is:

[0033] Where λ is the wavelength and D is the distance between two array elements.

[0034] The calculation formula for the deflection angle is:

[0035] In the formula, θ 实 is the real-time deflection angle, and θ0 is the initial deflection angle.

[0036] In step S4, the monitor 50 uses the servo control data frame to send the deflection angle of the directional antenna 20 to the servo controller 60, and the servo controller 60 controls the servo turntable 10 to rotate so that the directional antenna 20 is aimed at the drone.

[0037] The above are only preferred embodiments of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A phase zeroing device for tracking and measuring angles of unmanned aerial vehicles, characterized in that: include: Servo turntable; A directional antenna, fixed on the servo turntable, the directional antenna is used to receive telemetry radio frequency signals; Connected to the ground terminal via a radio frequency cable; A ground terminal connected to the directional antenna, the ground terminal is used to process the telemetry radio frequency signal received by the directional antenna to obtain telemetry data; An image collector is arranged on the directional antenna, and is used to collect images of the drone; A monitor connected to the image collector for adjusting the focal length of the image collector and displaying the drone image collected by the image collector; the monitor is also connected to the ground terminal for determining servo control data according to the telemetry data; A servo controller is connected to the servo turntable and the monitor, and is used to rotate the servo turntable according to the servo control data.

2. The UAV tracking angle measurement phase zeroing device according to claim 1 is characterized in that: The directional antenna is a dual-channel antenna.

3. The UAV tracking angle measurement phase zeroing device according to claim 2 is characterized in that: The ground terminal comprises: A frequency conversion sampler connected to the directional antenna, the frequency conversion sampler is used to convert the frequency and sample the telemetry radio frequency signal received by the directional antenna; A data processor connected to the frequency conversion sampler and the monitor, the data processor is used to process the frequency conversion and sampled signals to obtain telemetry data, and send the telemetry data to the monitor; The housing includes a variable frequency sampler and a data processor.

4. The UAV tracking angle measurement phase zeroing device according to claim 3 is characterized in that: The shell is provided with two radio frequency ports, and the two element interfaces of the directional antenna are respectively connected to the two radio frequency ports via radio frequency cables.

5. The UAV tracking angle measurement phase zeroing device according to claim 3 is characterized in that: The frequency conversion sampler is an AD9361 radio frequency chip.

6. The UAV tracking angle measurement phase zeroing device according to claim 3 is characterized in that: The data processor is a ZYNQ7100 chip.

7. A method for zeroing phase of UAV tracking angle measurement, characterized in that: The zero calibration device according to any one of claims 2 to 6 comprises: Before the drone takes off, the monitor sends servo control data to the servo controller and adjusts the focal length of the image collector. The servo controller controls the servo turntable to rotate and adjust the angle of the directional antenna so that the drone is located in the center of the field of view of the image collector. The ground terminal determines the initial phase difference between the two receiving channels according to the telemetry radio frequency signals received by the two receiving channels, and determines the initial deflection angle of the directional antenna according to the initial phase difference; After the UAV takes off, the ground terminal determines the real-time phase difference between the two receiving channels according to the telemetry radio frequency signals received by the two receiving channels, determines the real-time deflection angle of the directional antenna according to the real-time phase difference, determines the required deflection angle of the directional antenna according to the real-time deflection angle and the real-time deflection angle, and sends the required deflection angle of the directional antenna to the monitor; The monitor sends the required deflection angle of the directional antenna to the servo controller, and the servo controller controls the servo turntable to rotate so that the directional antenna is aimed at the drone.

8. The method for zeroing the phase of the UAV tracking angle measurement according to claim 7 is characterized in that: The calculation formula of phase difference is: In the formula, Q A , Q B are the orthogonal components of the signals of the two receiving channels, I A ,I B are the in-phase components of the signals of the two receiving channels respectively.

9. The method for zeroing the phase of the UAV tracking angle measurement according to claim 7, characterized in that: The calculation formula for the deflection angle is: Where λ is the wavelength, D is the distance between two channel array elements, is the phase difference.

10. The method for zeroing the phase of the UAV tracking angle measurement according to claim 7, characterized in that: The calculation formula for the deflection angle is: In the formula, θ 实 is the real-time deflection angle, and θ0 is the initial deflection angle.

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