Laser terminal function transfer test system based on light beam servo and method thereof

Abstract

The invention belongs to the field of space laser communication, and particularly relates to a laser terminal function transfer test system and method based on light beam servo. The optical fiber laser is used for emitting tracking light; the optical frequency sweeping module is used for realizing dynamic tracking light spot simulation and providing dynamic tracking light for the communication terminal; the sub light path module is used for realizing the change of a light path; the monitoring acquisition module is used for monitoring the light spot position in real time and dynamically displaying the light spot position; and the control analysis module is used for processing data read by the control panel. The method is used for solving the problem that the tracking precision of the laser terminal is influenced by random interference and vibration of an installation platform in the optical signal transmission process in the prior art.

Description

Technical Field

[0001] The invention belongs to the field of space laser communication, and in particular relates to a laser terminal transmission function testing system based on beam servo and a method thereof. Background Art

[0002] Laser communication usually uses optical fiber or free space to transmit signals, and can achieve high-speed, high-bandwidth, and long-distance communication. Compared with microwave communication, laser communication has faster transmission rates, larger communication capacity, smaller terminal size and power consumption, and stronger anti-interference ability and security. Based on the above characteristics, laser terminals are gradually widely carried on satellites, aircraft, and airship platforms.

[0003] At present, laser terminals are developing towards miniaturization and lightness, which puts forward higher requirements for their tracking accuracy. Random interference in the optical signal transmission process and vibration of the laser terminal installation platform pose challenges to the establishment and stability of the laser terminal communication link. Summary of the invention

[0004] The present invention provides a laser terminal transmission function test system based on beam servo and a method thereof, which are used to solve the problem of the influence of random interference in the signal transmission process and the vibration of the laser terminal installation platform on the tracking accuracy in the prior art.

[0005] The present invention is achieved through the following technical solutions:

[0006] A laser terminal transmission function test system based on beam servo, the laser terminal transmission function test system comprises a laser, an optical frequency scanning module, a sub-optical path module, a monitoring and acquisition module and a control and analysis module, the control and analysis module is connected to the monitoring and acquisition module, and the monitoring and acquisition module is respectively connected to the optical frequency scanning module and the sub-optical path module;

[0007] The fiber laser is used to emit tracking light;

[0008] The optical frequency scanning module is used to realize dynamic tracking light spot simulation and provide dynamic tracking light for the communication terminal;

[0009] The sub-optical path module is used to realize the change of the optical path;

[0010] The monitoring and acquisition module is used to monitor the light spot position in real time and display it dynamically;

[0011] The control analysis module is used to process the data read from the control panel.

[0012] Furthermore, the tracking light emitted by the fiber laser 1 is reflected by the fast reflector FSM2 installed at 45 degrees, and the light transmitted by the beam splitter 3 is then reflected by the reflector 4 and sequentially passes through the secondary mirror 7-1, the primary mirror 7-2 and the off-axis parallel light pipe 7-3 to the laser terminal 10 to be measured, providing a moving target for it;

[0013] The light reflected by the beam splitter 3 is reflected by the return reflector 8 and converges to the camera 9, representing the tracking light;

[0014] The light emitted by the laser terminal 10 to be tested passes through the off-axis collimator 7-3, then passes through the primary mirror 7-2 and the secondary mirror 7-1, and then is reflected by the reflector 4, and then is beam-contracted by the light pipe, and then reflected by the beam splitter 3 and focused to the camera 9, representing the terminal emitted light.

[0015] Furthermore, the fast mirror FSM2 installed at 45° of the optical frequency scanning system and the driver of the optical frequency scanning system transmit signals bidirectionally via the serial port, and the camera 9 of the monitoring and acquisition module communicates with the image tracking board of the monitoring and acquisition module via the Cameralink interface to transmit signals;

[0016] The driver of the optical frequency scanning system and the image tracking board of the monitoring and acquisition module transmit signals to the control board of the control and analysis system via the serial port in both directions. The control board of the control and analysis system transmits signals to the host computer of the control and analysis system via the serial port in both directions. The host computer of the control and analysis system transmits signals to the display screen of the industrial computer of the control and analysis system via the serial port in both directions.

[0017] The industrial computer of the control and analysis system completes the control and analysis through the analysis software of the host computer.

[0018] A laser terminal transmission function testing method based on beam servo, the laser terminal transmission function testing method specifically comprises the following steps:

[0019] Step 1: Assemble and debug the laser terminal transmission test system based on beam servo;

[0020] Step 2: The control and analysis system uses the received tracking light spot and emission light spot to identify the mathematical model of the terminal to be tested and analyze the miss-target amount of the tracking light spot and the emission light spot;

[0021] Step 3: Based on the analysis in step 2, obtain the control system parameters of the terminal to be tested.

[0022] Furthermore, the analysis method of step 2 comprises the following steps:

[0023] Step 2.1: The tracking light spot is used as the input u(k) of the system under test, and the emission light spot is used as the output y(k) of the system under test. When performing spectrum analysis on the signal, a DFT function model is constructed based on the information set by the user's frequency sweep.

[0024] Step 2.2: Calculate the tracking accuracy based on the position of the tracking spot and the emission spot. The tracking error is defined as: e(k) = u(k) - y(k). Calculate all stored data and calculate the RMS, which is the tracking accuracy of the terminal under test.

[0025] Furthermore, the model of constructing the DFT function in step 2.1 is specifically as follows:

[0026]

[0027] Among them, N is the number of points of the time domain discrete signal, n is the number of the time domain discrete signal, k is the number of the frequency domain signal, and the number of points of the frequency domain signal is also N. According to Euler's formula:

[0028] e -jω =cos(ω)-jsin(ω) (2)

[0029] The discrete Fourier transform is written as follows:

[0030]

[0031] The system discretely samples the signal based on the frequency fs and obtains a discrete input signal with N sampling points. Subsequently, in the process of calculating DFT, the sampling point N in the sine / cosine expression is used as the independent variable. According to the DFT calculation formula, the complex domain representation of the frequency domain signal with the highest correlation with the sample is obtained. The amplitude and phase information of the input signal can be obtained through the real and imaginary part information. Similarly, the system input u(k) and the system output y(k) are processed respectively to obtain the amplitude-frequency and phase-frequency characteristic curves of the closed-loop system, that is, the closed-loop Bode diagram.

[0032] Furthermore, the step 3 is specifically to measure the closed-loop mathematical model of the laser terminal based on step 2, obtain the control bandwidth, error suppression bandwidth, and tracking accuracy parameters of the system, thereby obtaining the open-loop frequency response of the laser terminal, and obtaining the open-loop cutoff frequency and stability margin parameters.

[0033] Furthermore, assuming that the terminal to be tested is a unit negative feedback system, when analyzing the open-loop transfer function of the system, the input is e(k) and the output is y(k). The amplitude-frequency and phase-frequency characteristic curves of the open-loop system, i.e., the open-loop Bode diagram, can be obtained by processing the data using the method in step 2.1. In the open-loop Bode diagram, the frequency with an amplitude of 0dB is the open-loop cutoff frequency, and the phase difference between the corresponding phase and -180° is the phase margin;

[0034] The tracking spot is used as the input u(k) of the system to be tested, and the tracking error spot position is used as the output e(k), or the real-time difference between the tracking spot and the emission spot position in step 2.1 is used as the tracking error output. The DFT method in step 2.1 is used for analysis to obtain the error transfer frequency characteristic curve of the terminal to be tested, that is, the error transfer function Bode diagram;

[0035] In the error transfer function Bode diagram, the frequency point corresponding to the amplitude of -3dB is the error suppression bandwidth of the system.

[0036] A computer device comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the above method is implemented.

[0037] The beneficial effects of the present invention are:

[0038] The present invention can image the tracking spot and the emission spot in different areas and use the same camera to image them, eliminating the need for additional time synchronization and eliminating the differences in camera performance. If two spots are collected by a camera respectively, in order to ensure that the spots are imaged at the same time, an additional time synchronization signal needs to be sent. The unequal delay of the hardware and the differences in the performance of different cameras increase the complexity of subsequent analysis.

[0039] The present invention adopts the light beam measurement method to perform modular analysis on the transmission function test system, and studies and analyzes the key technologies therein, such as dynamic light scanning, dual-spot centroid extraction, high-efficiency multi-mode model identification algorithm, etc., simulates the laser terminal alignment and tracking process, and provides a test method and system for analyzing the servo performance of the laser terminal. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a structural schematic diagram of the present invention.

[0041] Figure 2 It is the system optical path diagram of the present invention.

[0042] Figure 3 It is the optical signal and electrical signal flow chart of the present invention. DETAILED DESCRIPTION

[0043] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0044] It should be understood that when used in this specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0045] It should also be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the application. As used in this application specification and the appended claims, the singular forms "a", "an" and "the" are intended to include plural forms unless the context clearly indicates otherwise.

[0046] The following is attached to this application specification Figure 1-3 , the technical solutions in the embodiments of the present application are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0047] In the following description, many specific details are set forth to facilitate a full understanding of the present application, but the present application may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0048] Implementation Method 1

[0049] This embodiment provides a laser terminal transmission function test system based on beam servo, the laser terminal transmission function test system includes a laser, an optical frequency scanning module, a sub-optical path module, a monitoring and acquisition module and a control and analysis module, the control and analysis module is connected to the monitoring and acquisition module, and the monitoring and acquisition module is respectively connected to the optical frequency scanning module and the sub-optical path module;

[0050] The fiber laser is used to emit tracking light;

[0051] The optical frequency scanning module is used to realize dynamic tracking light spot simulation and provide dynamic tracking light for the communication terminal;

[0052] The sub-optical path module is used to realize the change of the optical path;

[0053] The monitoring and acquisition module is used to monitor the light spot position in real time and display it dynamically;

[0054] The control analysis module is used to process the data read from the control panel.

[0055] Furthermore, the tracking light emitted by the fiber laser 1 is reflected by the fast reflector FSM2 installed at 45 degrees, and the light transmitted by the beam splitter 3 is then reflected by the reflector 4 and sequentially passes through the secondary mirror 7-1, the primary mirror 7-2 and the off-axis parallel light pipe 7-3 to the laser terminal 10 to be measured, providing a moving target for it;

[0056] The light reflected by the beam splitter 3 is reflected by the return reflector 8 and converges to the camera 9, representing the tracking light;

[0057] The light emitted by the laser terminal 10 to be tested passes through the off-axis collimator 7-3, then passes through the primary mirror 7-2 and the secondary mirror 7-1, and then is reflected by the reflector 4, and then is beam-contracted by the light pipe, and then reflected by the beam splitter 3 and focused to the camera 9, representing the terminal emitted light.

[0058] The tracking light emitted by the fiber laser 1 is transmitted to the off-axis parallel light pipe 7 of the sub-optical path module and the camera 9 of the monitoring and acquisition module respectively through the fast reflection mirror FSM2 installed at 45 degrees of the optical scanning system and the beam splitter 3 of the sub-optical path module;

[0059] The tracking light passing through the off-axis collimator 7 reaches the laser terminal 10 to be measured, and is used to track the moving target;

[0060] The terminal emission light emitted by the laser terminal 10 to be tested passes through the off-axis parallel light pipe 7 to the beam splitter 3 of the sub-optical path module, and the beam splitter 3 of the sub-optical path module transmits the terminal emission light to the camera 9 of the monitoring and acquisition module. This beam of light does not reach the fast mirror, and the wavelength characteristics of the beam splitter cause the terminal emission light to be unable to pass through and reach the fast mirror.

[0061] Furthermore, the fast mirror FSM2 installed at 45° of the optical frequency scanning system and the driver of the optical frequency scanning system transmit signals bidirectionally via the serial port, and the camera 9 of the monitoring and acquisition module communicates with the image tracking board of the monitoring and acquisition module via the Cameralink interface to transmit signals;

[0062] The driver of the optical frequency scanning system and the image tracking board of the monitoring and acquisition module transmit signals to the control board of the control and analysis system via the serial port in both directions. The control board of the control and analysis system transmits signals to the host computer of the control and analysis system via the serial port in both directions. The host computer of the control and analysis system transmits signals to the display screen of the industrial computer of the control and analysis system via the serial port in both directions.

[0063] The industrial computer of the control and analysis system completes the control and analysis through the analysis software of the host computer.

[0064] Specifically, the sub-optical path module cooperates with the optical scanning module, and the optical scanning module sets the vibration simulator parameters according to the user interaction information to simulate the target equivalent motion information, common random interference factors in the optical signal transmission process and the vibration characteristics of the terminal platform.

[0065] The tracking light emitted by the laser in the transmission test system is reflected by the fast reflector installed at 45 degrees. Part of the light passes through the energy beam splitter, is reflected by the reflector, and is sent to the laser terminal through the off-axis collimator to provide a moving target. Part of the light is first reflected by the energy beam splitter, then reflected by the return reflector, and then converged to the camera and enters the monitoring and acquisition module. The laser terminal also emits a beam of light, which is reflected by the reflector through the off-axis collimator, and then is reduced in size by the light tube, reflected by the beam splitter, and then focused to the camera and enters the monitoring and acquisition module.

[0066] The motion information simulated by the optical frequency scanning module is realized by a fast mirror (i.e., a vibration simulator). Since the system can simulate vibration information with a frequency of up to 1kHz, the fast mirror drive control bandwidth is required to be very high to simulate motion information: sine wave, white noise, PSD vibration spectrum (up to 1kHz).

[0067] The monitoring and acquisition module provides analytical data for the control and analysis module by simultaneously acquiring the positions of the tracking light and the emission light spots. The camera in the monitoring and acquisition module can partition the tracking light spots and the emission light spots for imaging, reducing the complexity of software and hardware design caused by the asynchrony of imaging between different cameras. The image tracking board in the monitoring and acquisition module uses three algorithms: image segmentation, centroid extraction, and position calculation to process the received light spots.

[0068] In the image tracking board, the camera detects 2 light spots at the same time, so the number of targets in the image is 2. By default, the vertical center of the image is used as the dividing line (configurable), and the dividing line divides the image into the left image and the right image. There is 1 target in the left image and 1 target in the right image. When an external device sends the image dividing line position to the image tracking board, this dividing line position has a higher priority than the default dividing line position.

[0069] The image tracking board first calculates the threshold of the left image and the threshold of the right image. When the image gray value is less than the threshold, it is considered background or noise. The centroid algorithm is used to calculate the pixels in the left image whose gray value is greater than the threshold to obtain the horizontal and vertical coordinates of the target in the left image. The centroid algorithm is used to calculate the pixels in the right image whose gray value is greater than the threshold to obtain the horizontal and vertical coordinates of the target in the right image.

[0070] In the control and analysis module, the control system analysis software is the core, which mainly includes functions such as signal output, data processing and analysis, and information interaction. It can configure camera parameters and vibration simulator parameters, output a variety of different sweep signal types, parse and analyze the read tracking spot and emission spot position data, and display the results.

[0071] The laser terminal transmission test system based on beam servo tests the closed-loop and open-loop mathematical models of the laser terminal based on the dynamic optical closed-loop frequency sweep method to evaluate the servo performance of the laser terminal. At the same time, the beam measurement method is used to more directly simulate the actual working state of the laser terminal, which helps to improve the servo performance of the laser terminal. It can provide ground testing for on-board laser terminals, further improve the tracking performance of laser terminals, and provide guarantee for the stability of laser communication links.

[0072] Implementation Method 2

[0073] A laser terminal transmission function testing method based on beam servo, the laser terminal transmission function testing method specifically comprises the following steps:

[0074] Step 1: Assemble and debug the laser terminal transmission test system based on beam servo;

[0075] Specifically, the fiber laser is used to emit tracking light;

[0076] The optical frequency scanning module is used to realize dynamic tracking light spot simulation and provide dynamic tracking light for the communication terminal;

[0077] The sub-optical path module is used to realize the change of the optical path;

[0078] The monitoring and acquisition module is used to monitor the light spot position in real time and display it dynamically;

[0079] The control analysis module is used to process the data read from the control panel.

[0080] Furthermore, the tracking light emitted by the fiber laser 1 is reflected by the fast reflector FSM2 installed at 45 degrees, and the light transmitted by the beam splitter 3 is then reflected by the reflector 4 and sequentially passes through the secondary mirror 7-1, the primary mirror 7-2 and the off-axis parallel light pipe 7-3 to the laser terminal 10 to be measured, providing a moving target for it;

[0081] The light reflected by the beam splitter 3 is reflected by the return reflector 8 and converges to the camera 9, representing the tracking light;

[0082] The light emitted by the laser terminal 10 to be tested passes through the off-axis collimator 7-3, then passes through the primary mirror 7-2 and the secondary mirror 7-1, and then is reflected by the reflector 4, and then is beam-contracted by the light pipe, and then reflected by the beam splitter 3 and focused to the camera 9, representing the terminal emitted light.

[0083] Step 2: The control and analysis system uses the received tracking light spot and emission light spot to identify the mathematical model of the terminal to be tested and analyze the miss-target amount of the tracking light spot and the emission light spot;

[0084] Step 3: Based on the analysis in step 2, obtain the control system parameters of the terminal to be tested.

[0085] Furthermore, the analysis method of step 2 comprises the following steps:

[0086] Step 2.1: The tracking light spot is used as the input u(k) of the system under test, and the emission light spot is used as the output y(k) of the system under test. When performing spectrum analysis on the signal, a DFT function model is constructed based on the information set by the user's frequency sweep.

[0087] Step 2.2: Calculate the tracking accuracy based on the position of the tracking spot and the emission spot. The tracking error is defined as: e(k) = u(k) - y(k). Calculate all stored data and calculate the RMS, which is the tracking accuracy of the terminal under test.

[0088] Furthermore, the model of constructing the DFT function in step 2.1 is specifically as follows:

[0089]

[0090] Among them, N is the number of points of the time domain discrete signal, n is the number of the time domain discrete signal, ranging from 0 to N-1, k is the number of the frequency domain signal, ranging from 0 to N-1, and the number of points of the frequency domain signal is also N. According to Euler's formula:

[0091] e -jω =cos(ω)-jsin(ω) (2)

[0092] The discrete Fourier transform is written as follows:

[0093]

[0094] The system discretely samples the signal based on the frequency fs to obtain a discrete input signal with N sampling points. Subsequently, in the process of calculating DFT, the sampling point N in the sine / cosine expression is used as the independent variable. According to the DFT calculation formula, the complex domain representation of the frequency domain signal with the highest correlation with the sample is obtained. The amplitude and phase information of the input signal can be obtained through the real and imaginary part information. Similarly, the system input u(k) and the system output y(k) are processed respectively to obtain the amplitude-frequency and phase-frequency characteristic curves of the closed-loop system, that is, the closed-loop Bode diagram. In the closed-loop Bode diagram, the frequency point corresponding to the amplitude attenuation of 3dB or the phase lag of 90° is the closed-loop control bandwidth.

[0095] Furthermore, the step 3 is specifically to measure the closed-loop mathematical model of the laser terminal based on step 2, obtain the system's control bandwidth, error suppression bandwidth, tracking accuracy and other parameters, thereby obtaining the open-loop frequency response of the laser terminal, and obtaining the open-loop cutoff frequency, stability margin and other parameters.

[0096] Furthermore, assuming that the terminal to be tested is a unit negative feedback system, when analyzing the open-loop transfer function of the system, the input is e(k) and the output is y(k). The amplitude-frequency and phase-frequency characteristic curves of the open-loop system, i.e., the open-loop Bode diagram, can be obtained by processing the data using the method in step 2.1. In the open-loop Bode diagram, the frequency with an amplitude of 0dB is the open-loop cutoff frequency, and the phase difference between the corresponding phase and -180° is the phase margin;

[0097] The tracking spot is used as the input u(k) of the system to be tested, and the tracking error spot position is used as the output e(k), or the real-time difference between the tracking spot and the emission spot position in step 2.1 is used as the tracking error output. The DFT method in step 2.1 is used for analysis to obtain the error transfer frequency characteristic curve of the terminal to be tested, that is, the error transfer function Bode diagram.

[0098] In the error transfer function Bode diagram, the frequency point corresponding to the amplitude of -3dB is the error suppression bandwidth of the system.

[0099] It can also be expressed as: according to the off-target amount of the tracking spot emitted by the transmission function test system and the emission spot emitted by the terminal to be tested, the discrete Fourier analysis method is used for analysis to identify the mathematical model of the terminal to be tested. The tracking spot is used as the input u(k) of the system to be tested, and the emission spot is used as the output y(k) of the system to be tested, and the signal is subjected to spectrum analysis. The system discretely samples the system input u(k) and the system output y(k) signals based on the frequency fs (i.e., the image frame rate) to obtain a discrete input signal with N sampling points. According to the DFT calculation formula, the complex domain representation of the frequency domain signal with the highest correlation with the sample is obtained. The amplitude-frequency and phase-frequency characteristic curves of the closed-loop system, i.e., the closed-loop Bode diagram, can be obtained through the real and imaginary information. In the closed-loop Bode diagram, the frequency point corresponding to the amplitude attenuation of 3dB or the phase lag of 90° is the closed-loop control bandwidth; according to the statistical tracking accuracy of the tracking spot and the emission spot position, the tracking error is defined as: e(k) = u(k)-y(k), and all stored data are calculated and the RMS is statistically calculated, which is the tracking accuracy of the terminal under test; assuming that the terminal under test is a unit negative feedback system, when analyzing the open-loop transfer function of the system, the input is e(k) and the output is y(k), and the discrete Fourier analysis method is used to process the data to obtain the amplitude-frequency and phase-frequency characteristic curves of the open-loop system, that is, the open-loop Bode diagram. In the open-loop Bode diagram, the frequency with an amplitude of 0dB is the open-loop cutoff frequency, and the phase difference between the corresponding phase and -180° at this time is the phase margin.

[0100] Implementation Method 3

[0101] An embodiment of the present invention provides an electronic device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the memory is used to store software programs and modules, and the processor executes various functional applications and data processing by running the software programs and modules stored in the memory. The memory and the processor are connected via a bus. Specifically, the processor implements any step in the first embodiment above by running the computer program stored in the memory.

[0102] It should be understood that in the embodiments of the present invention, the processor referred to may be a central processing unit (CPU), and the processor may also be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0103] The memory may include a read-only memory, a flash memory, and a random access memory, and provides instructions and data to the processor. A part or all of the memory may also include a nonvolatile random access memory.

[0104] As can be seen from the above, the electronic device provided by the embodiment of the present invention can implement the laser terminal transfer function test method based on beam servo as described in the second embodiment by running a computer program. Based on the system of the first embodiment, the tracking spot and the emission spot are analyzed by discrete Fourier analysis method to obtain the amplitude-frequency and phase-frequency characteristic curves of the closed-loop system of the terminal to be tested, that is, the closed-loop Bode diagram. The amplitude-frequency and phase-frequency characteristic curves of the open-loop system, that is, the open-loop Bode diagram, can also be obtained. At the same time, the position of the tracking spot and the emission spot is subtracted in real time as the tracking error output, and the discrete Fourier analysis method is used for analysis to obtain the error transfer frequency characteristic curve of the terminal to be tested, that is, the error transfer function Bode diagram.

[0105] It should be understood that if the above-mentioned integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the present invention implements all or part of the processes in the above-mentioned implementation method, and can also be completed by instructing the relevant hardware through a computer program. The above-mentioned computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method implementations when executed by the processor. Among them, the above-mentioned computer program includes computer program code, and the above-mentioned computer program code can be in source code form, object code form, executable file or some intermediate form. The above-mentioned computer-readable medium may include: any entity or device capable of carrying the above-mentioned computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the above-mentioned computer-readable storage medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction.

[0106] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest range consistent with the principles and novel features disclosed herein.

[0107] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In actual applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the above-mentioned device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the implementation method can be integrated into a processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of the present invention. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method implementation method, which will not be repeated here.

[0108] It should be noted that the methods and detailed examples provided in the above embodiments can be combined with the devices and equipment provided in the embodiments, and references can be made to each other, and no further details will be given.

[0109] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0110] In the embodiments provided by the present invention, it should be understood that the disclosed device / terminal equipment and method can be implemented in other ways. For example, the device / equipment implementation described above is only illustrative, for example, the division of the above modules or units is only a logical function division, and in actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed.

[0111] The above-mentioned embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the above-mentioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above-mentioned embodiments, or replace some of the technical features therein by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A laser terminal transmission function test system based on beam servo, characterized in that: The laser terminal transmission test system includes a laser, an optical frequency scanning module, a sub-optical path module, a monitoring and acquisition module and a control and analysis module, wherein the control and analysis module is connected to the monitoring and acquisition module, and the monitoring and acquisition module is respectively connected to the optical frequency scanning module and the sub-optical path module; The fiber laser is used to emit tracking light; The optical frequency scanning module is used to realize dynamic tracking light spot simulation and provide dynamic tracking light for the communication terminal; The sub-optical path module is used to realize the change of the optical path; The monitoring and acquisition module is used to monitor the light spot position in real time and display it dynamically; The control analysis module is used to process the data read from the control panel.

2. The laser terminal transmission function test system according to claim 1, characterized in that: The tracking light emitted by the fiber laser (1) is reflected by a fast reflector mirror (FSM) (2) installed at 45 degrees, and the light transmitted by the beam splitter (3) is then reflected by a reflector (4) and sequentially passes through a secondary mirror (7-1), a primary mirror (7-2) and an off-axis parallel light pipe (7-3) to a laser terminal (10) to be measured, thereby providing a moving target for the laser terminal; The light reflected by the beam splitter (3) is reflected by the return light reflector (8) and converges to the camera (9), representing the tracking light; The light emitted by the laser terminal (10) to be tested passes through the off-axis collimator (7-3) in sequence through the primary mirror (7-2) and the secondary mirror (7-1), is reflected by the reflector (4), is subjected to light tube beam reduction processing, is reflected by the beam splitter (3), and is focused to the camera (9), thereby representing the light emitted by the terminal.

3. The laser terminal transmission function test system according to claim 1, characterized in that: The fast reflection mirror FSM (2) installed at 45 degrees of the optical scanning system and the driver of the optical scanning system transmit signals bidirectionally via a serial port, and the camera (9) of the monitoring and acquisition module communicates with the image tracking board of the monitoring and acquisition module via a Cameralink interface to transmit signals; The driver of the optical frequency scanning system and the image tracking board of the monitoring and acquisition module transmit signals to the control board of the control and analysis system via the serial port in both directions. The control board of the control and analysis system transmits signals to the host computer of the control and analysis system via the serial port in both directions. The host computer of the control and analysis system transmits signals to the display screen of the industrial computer of the control and analysis system via the serial port in both directions. The industrial computer of the control and analysis system completes the control and analysis through the analysis software of the host computer.

4. A laser terminal transmission function test method based on beam servo, characterized in that: The laser terminal transmission function testing method specifically comprises the following steps: Step 1: Assemble and debug the laser terminal transmission function test system based on beam servo as claimed in claim 1; Step 2: The control and analysis system uses the received tracking light spot and emission light spot to identify the mathematical model of the terminal to be tested and analyze the miss-target amount of the tracking light spot and the emission light spot; Step 3: Based on the analysis in step 2, obtain the control system parameters of the terminal to be tested.

5. The laser terminal transmission function testing method according to claim 4, characterized in that: The analysis method of step 2 comprises the following steps: Step 2.1: The tracking light spot is used as the input u(k) of the system under test, and the emission light spot is used as the output y(k) of the system under test. When performing spectrum analysis on the signal, a DFT function model is constructed based on the information set by the user's frequency sweep. Step 2.2: Calculate the tracking accuracy based on the position of the tracking spot and the emission spot. The tracking error is defined as: e(k) = u(k) - y(k). Calculate all stored data and calculate the RMS, which is the tracking accuracy of the terminal under test.

6. The laser terminal transmission function testing method according to claim 5, characterized in that: The step 2.1 constructs the model of the DFT function as follows: Among them, N is the number of points of the time domain discrete signal, n is the number of the time domain discrete signal, k is the number of the frequency domain signal, and the number of points of the frequency domain signal is also N. According to Euler's formula: e -jω =cos(ω)-jsin(ω) (2) The discrete Fourier transform is written as follows: The system discretely samples the signal based on the frequency fs and obtains a discrete input signal with N sampling points. Subsequently, in the process of calculating DFT, the sampling point N in the sine / cosine expression is used as the independent variable. According to the DFT calculation formula, the complex domain representation of the frequency domain signal with the highest correlation with the sample is obtained. The amplitude and phase information of the input signal can be obtained through the real and imaginary part information. Similarly, the system input u(k) and the system output y(k) are processed respectively to obtain the amplitude-frequency and phase-frequency characteristic curves of the closed-loop system, that is, the closed-loop Bode diagram.

7. The laser terminal transmission function testing method according to claim 4, characterized in that: Specifically, step 3 is to measure the closed-loop mathematical model of the laser terminal based on step 2, obtain the control bandwidth, error suppression bandwidth, and tracking accuracy parameters of the system, thereby obtaining the open-loop frequency response of the laser terminal, and obtaining the open-loop cutoff frequency and stability margin parameters.

8. The laser terminal transmission function testing method according to claim 7, characterized in that: It is assumed that the terminal to be tested is a unit negative feedback system. When analyzing the open-loop transfer function of the system, the input is e(k) and the output is y(k). The amplitude-frequency and phase-frequency characteristic curves of the open-loop system, i.e., the open-loop Bode diagram, can be obtained by processing the data using the method in step 2.

1. In the open-loop Bode diagram, the frequency with an amplitude of 0 dB is the open-loop cutoff frequency, and the phase difference between the corresponding phase and -180° at this time is the phase margin. The tracking spot is used as the input u(k) of the system to be tested, and the tracking error spot position is used as the output e(k), or the real-time difference between the tracking spot and the emission spot position in step 2.1 is used as the tracking error output. The DFT method in step 2.1 is used for analysis to obtain the error transfer frequency characteristic curve of the terminal to be tested, that is, the error transfer function Bode diagram; In the error transfer function Bode diagram, the frequency point corresponding to the amplitude of -3dB is the error suppression bandwidth of the system.

9. A computer device, characterized in that: The method comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the method according to any one of claims 4 to 7 is implemented.

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