Tracking precision measuring device for unmanned aerial vehicle-mounted laser communication terminal

Abstract

The utility model relates to an unmanned aerial vehicle-mounted laser communication terminal tracking precision measuring device, which comprises an air floatation optical platform, an electric turntable, a laser and a six-degree-of-freedom motion platform are arranged on the air floatation optical platform, an emission lens module is arranged on the electric turntable, the laser is arranged on one side of the emission lens module, and the six-degree-of-freedom motion platform is arranged on the other side of the emission lens module. The transmitting lens module is connected through an optical fiber; the six-degree-of-freedom motion platform is arranged on the other side of the electric rotary table, an airborne laser communication terminal is placed on the six-degree-of-freedom motion platform and is opposite to the transmitting lens module, the airborne laser communication terminal is aligned with the optical axis of the transmitting lens module, and the airborne laser communication terminal is connected with a PC terminal through a line. The device is simple in principle, convenient to operate and easy to realize, does not need to carry out long-distance tracking precision actual measurement outdoors, and only needs to carry out dynamic tracking test under an equivalent distance indoors according to the outdoor communication distance and the movement speed of the unmanned aerial vehicle, thereby verifying the precision of a tracking algorithm.

Description

Technical Field

[0001] The utility model relates to a tracking accuracy measuring device for an unmanned aerial vehicle-borne laser communication terminal, belonging to the technical field of airborne laser communication. Background Art

[0002] Laser communication has outstanding advantages such as good confidentiality, high transmission rate, large communication capacity, and strong anti-interference ability. Airborne laser communication can achieve high-mobility reconnaissance tasks and other goals at long distances. The establishment of a laser communication link requires the laser communication terminals of both parties to complete rapid capture and line of sight alignment. The line of sight alignment is achieved through tracking, among which the coarse tracking servo unit mainly completes rapid capture and large-range tracking tasks, and is an important part of the laser communication terminal servo system. Therefore, it is necessary to test the accuracy of the system's coarse tracking to determine whether it can achieve dynamic tracking in a specific dynamic environment. At the same time, laser communication extremely requires high-precision stability to achieve dual-end communication. Therefore, high-precision and stable tracking, that is, fine tracking, is also an indispensable part of the laser communication tracking link, and its tracking accuracy also needs to be tested. Coarse and fine tracking cooperate with each other to complete high-precision tracking to ensure that the laser communication system has the ability to communicate stably.

[0003] In order to verify whether the tracking algorithm of the system can meet the design requirements, it is necessary not only to derive verification indicators through theoretical calculations, but also to build a laser communication terminal tracking accuracy measurement device and method that can be used indoors in the laboratory for verification. Moreover, the device needs to have the function of simulating the long-distance working environment of the UAV platform. Summary of the invention

[0004] The purpose of the utility model is to overcome the above-mentioned shortcomings and provide a measurement platform for the tracking accuracy of a space laser communication terminal, which can provide motion characteristics of a simulated airborne platform working environment and also verify the image stabilization function of the terminal.

[0005] According to the technical solution provided by the utility model, a tracking accuracy measuring device for an unmanned aerial vehicle laser communication terminal includes an air-floating optical platform, on which an electric turntable, a laser and a six-degree-of-freedom motion platform are arranged, a transmitting lens module is placed on the electric turntable, the laser is placed on one side of the transmitting lens module, and is connected to the transmitting lens module through an optical fiber; the six-degree-of-freedom motion platform is arranged on the other side of the electric turntable, on which an airborne laser communication terminal is placed, which is placed opposite to the transmitting lens module, and the optical axis of the airborne laser communication terminal is aligned with that of the transmitting lens module; the airborne laser communication terminal is connected to a PC end through a line.

[0006] As a further improvement of the present invention, a height adjustment frame is provided between the electric turntable and the transmitting lens module.

[0007] As a further improvement of the present invention, the transmitting lens module adopts a collimating lens.

[0008] As a further improvement of the present invention, the wavelength adopted by the laser is 1550nm, and the output power is not greater than 1W.

[0009] As a further improvement of the utility model, the electric turntable model is MGC104, the resolution is 0.00006°, and the repeat positioning accuracy is 0.002°.

[0010] As a further improvement of the present invention, the maximum load of the six-degree-of-freedom motion table is 20kg, and the repeated positioning accuracy is ±0.14um / ±0.05um.

[0011] The beneficial effects of the utility model are:

[0012] The utility model has a simple principle, convenient operation and is easy to implement. It only needs to perform an equivalent test indoors according to the outdoor communication distance and the speed of the UAV movement to verify the accuracy of the tracking algorithm.

[0013] By setting the parameters of the electric turntable, the relative motion state of the UAV platform can be simulated equivalently, and the tracking accuracy measurement task under different motion states can be completed; at the same time, a six-degree-of-freedom platform is set under the terminal, which can be used to simulate the low-frequency jitter of the UAV platform in the hovering state. Compared with the satellite-borne laser communication terminal, the airborne laser communication terminal requires image stabilization control, so the image stabilization system of the airborne laser communication terminal can also be tested in the design of this test platform. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the overall structure of the utility model.

[0015] Explanation of the reference numerals: 1. air-floating optical platform; 2. electric turntable; 3. laser; 4. airborne laser communication terminal; 5. six-degree-of-freedom motion platform; 6. transmitting lens module; 7. height adjustment frame. DETAILED DESCRIPTION

[0016] The present invention will be further described below with reference to the embodiments in the accompanying drawings:

[0017] As shown in the figure, a tracking accuracy measurement device for an unmanned aerial vehicle laser communication terminal includes an air-floating optical platform 1, on which an electric turntable 2, a laser 3 and a six-degree-of-freedom motion platform 5 are arranged, a transmitting lens module 6 is placed on the electric turntable 2, the laser 3 is placed on one side of the transmitting lens module 6, and is connected to the transmitting lens module 6 through an optical fiber; the six-degree-of-freedom motion platform 5 is arranged on the other side of the electric turntable 2, on which an airborne laser communication terminal 4 is placed, which is placed opposite to the transmitting lens module 6, and the optical axes of the airborne laser communication terminal 4 and the transmitting lens module 6 are aligned, and the airborne laser communication terminal 4 is connected to the PC end through a line.

[0018] A height adjustment frame 7 is provided between the electric turntable 2 and the transmitting lens module 6 for adjusting the optical axis alignment between the airborne laser communication terminal 4 and the transmitting lens module 6 .

[0019] The airborne laser communication terminal 4 has the function of image stabilization control. A gyroscope and an accelerometer are used to measure the terminal's attitude and position changes, and the combined measured data are processed. The azimuth axis and pitch axis motors inside the terminal are compensated and controlled according to the new data to achieve the effect of image stabilization. That is, when the terminal is subject to external interference, the terminal optical head can also always point to the same position.

[0020] The transmitting lens module 6 adopts a collimating lens; the wavelength adopted by the laser 3 is 1550nm, and the output power is not more than 1W. The laser receiving CCD camera inside the airborne laser communication terminal is 1550nm non-visible light, and the light receiving power of the CCD camera should not be too high to prevent breakdown damage; the electric turntable 2 model is MGC104, with a resolution of 0.00006°, a repeat positioning accuracy of 0.002°, and a programmable motion trajectory; the maximum load of the six-degree-of-freedom motion platform 5 is 20kg, and the repeat positioning accuracy is ±0.14um / ±0.05um. In addition to trajectory motion, there is mechanical vibration during the flight of the drone. Therefore, the airborne laser communication terminal will be affected by the vibration interference of the flight process. The high-precision programmable electric turntable can restore the measured vibration data through data programming for simulation testing. The weight of the processed parts of the airborne laser communication terminal is about 5kg, and the 20kg load-level high-precision six-degree-of-freedom platform can complete the accurate simulation of various flight conditions through multi-degree-of-freedom combined motion.

[0021] The method for measuring the tracking accuracy of an airborne laser communication terminal using the airborne laser communication terminal tracking accuracy measurement platform comprises the following steps:

[0022] Step 1: Build the test environment on the optical platform. The six-degree-of-freedom motion platform, electric turntable and laser are placed on the optical platform. The transmitting lens module is placed on the electric turntable. The airborne laser communication terminal is placed on the six-degree-of-freedom motion platform, and its optical axis is aligned with the optical axis of the transmitting lens module. The rear end of the transmitting lens module is connected to the laser using an optical fiber to provide simulated beacon light for tracking by the airborne laser communication terminal.

[0023] Step 2: Power on the airborne laser communication terminal and configure the parameters to put it in a standby state for normal operation;

[0024] Step 3: Turn on the laser and power on the electric turntable and the six-degree-of-freedom motion stage at the same time;

[0025] Step 4: Turn on the coarse tracking or fine tracking mode of the airborne laser communication terminal;

[0026] Step 5: Control the electric turntable to move at a speed of 0.1° / s to simulate the relative flight of the UAV in a long-distance environment; at the same time, input the measured airborne hovering vibration spectrum into the six-degree-of-freedom motion table to simulate the hovering state of the airborne platform;

[0027] Step 6: Record and track the deviation between the real-time spot position received by the CCD camera and the system optical axis, i.e., the miss distance (X, Y);

[0028] Step 7: Obtain the tracking accuracy of coarse tracking or fine tracking using the following calculation method according to the miss distance (X, Y);

[0029] According to the mean formula, the average value of the measured off-target amount sample data is calculated

[0030]

[0031] Where X i is the off-target amount (X, Y), n is the number of statistical samples;

[0032] Further, the standard deviation σ of the group of statistical sample data is calculated using the mean of the off-target amount sample data obtained in the previous step;

[0033]

[0034] The tracking accuracy index is This calculation formula is used for both coarse tracking and fine tracking.

Claims

1. A tracking accuracy measurement device for an unmanned aerial vehicle laser communication terminal, characterized in that: The invention comprises an air-floating optical platform (1), on which an electric turntable (2), a laser (3) and a six-degree-of-freedom motion platform (5) are arranged; a transmitting lens module (6) is placed on the electric turntable (2); the laser (3) is placed on one side of the transmitting lens module (6) and is connected to the transmitting lens module (6) via an optical fiber; the six-degree-of-freedom motion platform (5) is arranged on the other side of the electric turntable (2), on which an airborne laser communication terminal (4) is placed, which is opposite to the transmitting lens module (6), and the optical axes of the airborne laser communication terminal (4) and the transmitting lens module (6) are aligned; the airborne laser communication terminal (4) is connected to a PC terminal via a line.

2. The tracking accuracy measuring device for an unmanned aerial vehicle laser communication terminal according to claim 1, characterized in that: A height adjustment frame (7) is provided between the electric turntable (2) and the transmitting lens module (6).

3. The tracking accuracy measuring device for an unmanned aerial vehicle laser communication terminal according to claim 1, characterized in that: The transmitting lens module (6) adopts a collimating lens.

4. The tracking accuracy measuring device for an unmanned aerial vehicle laser communication terminal according to claim 1, characterized in that: The wavelength adopted by the laser (3) is 1550nm, and the output power is no more than 1W.

5. The tracking accuracy measuring device for an unmanned aerial vehicle laser communication terminal according to claim 1, characterized in that: The electric turntable (2) is of model MGC104, with a resolution of 0.00006° and a repeat positioning accuracy of 0.002°.

6. The tracking accuracy measuring device for an unmanned aerial vehicle laser communication terminal according to claim 1, characterized in that: The maximum load of the six-degree-of-freedom motion platform (5) is 20 kg, and the repeated positioning accuracy is ±0.14 um / ±0.05 um.

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