Laser communication system optical tracking point self-calibration method

Abstract

The invention relates to the technical field of wireless laser communication, in particular to a self-calibration method for an optical tracking point of a laser communication system, which comprises the following steps of: automatically adjusting the tracking point (x alpha, y beta), calculating the optimal value of Pbest under the tracking point (x alpha, y beta) by using a data statistics method according to acquired N groups of power values, and calculating the optimal value of Pbest under the tracking point (x alpha, y beta) according to the optimal value. The self-adaption of the optical tracking point of the wireless laser communication system is realized, and for airborne and satellite-borne laser communication equipment with complex operation environment and inconvenience in field debugging of the optical tracking point by debugging personnel, the tedious step of manual field parameter adjustment is omitted through the method; according to the fact that the coordinates of the optical tracking point can be influenced by equipment structure micro-deformation caused by different operation temperature environments, vibration or temperature, different communication distances, different light spot states and the like, the method can enable the whole optical tracking point calibration work to be subjected to full-automatic self-adaptive calibration under any operation environment condition; and the communication stability of the equipment is greatly improved while the labor cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of wireless laser communication, and in particular to a self-calibration method for optical tracking points of a laser communication system. Background Art

[0002] Laser communication technology is mainly used in the fields of intersatellite communication, satellite-to-ground communication, and high-altitude and high-speed air-based communication. During communication, the laser communication system has high requirements for the transceiver coaxiality. Usually, the satellite or airborne laser communication system terminal requires the beacon and signal divergence angle to be at the level of tens of micro-radians, and the transceiver coaxiality of the optical system should be controlled within a few micro-radians. When the laser communication terminal equipment is installed on the airborne or satellite platform, the micro-deformation of the optical path caused by the platform vibration and ambient temperature will affect the transceiver coaxiality of the laser communication system. The mechanical micro-deformation of the optical path may cause the actual tracking point to deviate from the tracking point calibrated on the ground. At a distance of hundreds or thousands of kilometers, two laser communication terminals complete dual-end capture tracking and maintain laser communication. The change of the optical tracking point directly affects the final communication quality. Therefore, it is necessary to self-calibrate the tracking point of the laser communication terminal.

[0003] Prior art CN109787686A discloses an on-orbit calibration and transceiver coaxiality correction device and method for a satellite optical communication terminal. A calibration reflector (corner cone) is installed outside the coarse pointing mechanism of the communication terminal to perform on-orbit self-calibration of the satellite laser communication equipment. The method adopts a 40mm inner rounded corner cone with a comprehensive error of about 1.5″, and adds signal calibration and beacon calibration transmission branches. It is a redundant design for the optical system. The self-transmitting and self-receiving calibration method can realize the recalibration of the optical tracking point of the optical system in principle. However, due to the certain error in the machining accuracy of the calibration reflector, the self-transmitting and self-receiving self-calibration method cannot take into account the influence of the communication distance, signal light energy intensity, atmospheric turbulence, etc. under actual working conditions, resulting in the final calibrated optical tracking point and the actual optical tracking point. There is still a deviation.

[0004] Prior art CN114200687A discloses a novel optical self-calibration device and method for a laser communication system. This method uses three fast reflectors on the optical path to correct the parallelism of the capture tracking branch, the communication transmitting branch and the communication receiving branch. The tracking center of the detector calibrated on the ground is used as a reference. By correcting the position of the deflection of the fast reflector, the optical path with slight deformation is corrected to achieve self-calibration of the optical path tracking point. By controlling the three fast reflectors installed on the optical path, the actual optical tracking point (x0±α, y0±β) is corrected to the position of the optical tracking point (x0, y0) calibrated in the laboratory. This method increases the scale of the driving circuit, increases the weight, volume and power consumption of the optical-mechanical system, introduces assembly errors, and increases the cost of developing the optical path. Summary of the invention

[0005] The main purpose of the present invention is to solve the problem of self-calibration of optical tracking points of a wireless laser communication system, and to provide a method for self-calibration of optical tracking points of a laser communication system. The method does not require a complex optical path structure, and provides a fully automatic optical tracking point calibration process. The optical tracking points can be self-calibrated within the receiving field of view of the tracking unit, and no redundant calibration optical path is required, so as to reduce the weight and cost of the optical machine. At the same time, in order to solve the problems of mechanical micro-deformation caused by platform vibration and thermal deformation, and deviation of the optical tracking points of the optical system due to the influence of communication distance, laser energy intensity, atmospheric turbulence, etc., the present invention can realize automatic calibration of the optical tracking points of the optical system. For platforms with high difficulty in online debugging such as underwater, airborne, and satellite-borne, the method can improve the stability of the communication system, optimize the energy utilization rate of laser emission and reception of the laser communication system, and thereby improve the stability of data transmission.

[0006] To achieve the above object, the present invention provides a laser communication system optical tracking point self-calibration method, comprising the following steps:

[0007] First, perform optical debugging. By adjusting the spot tracking unit, adjust the received signal optical power value detected by the power detector of the signal light receiving unit to the maximum value P max ;

[0008] At this time, the light beam will pass through the beam splitter and hit the tracking detector at the other end, and the spot position at this time will be adjusted to the center of the spot position detector, and the center is the optical tracking point (x0, y0);

[0009] Afterwards, the laser emitting module emits a laser beam, and the laser beam is received by the light spot position detector and the signal light receiving unit;

[0010] Then the laser beam received by the light spot position detector and the signal light receiving unit is split into two by the beam splitter;

[0011] Automatically adjust the position of the laser beam so that the spot position follows the position adjustment of the laser beam. The spot position is the actual tracking point (x α ,y β );

[0012] Collect N groups of optical power values ​​of the received signals, and use data statistics to calculate the optical power values ​​at the actual tracking point (x α ,y β ) best The optimal value of the optical tracking point is obtained to complete the self-calibration process of the optical tracking point.

[0013] Among them, the optical tracking point (x0, y0) obtained in the laboratory debugging will deviate from the optical tracking point in actual use, which is mainly manifested in that after the spot position detector detects the spot position and turns on the tracking function, when the spot tracking unit locks the spot position on the target surface (x0, y0) of the spot position detector, the signal light receiving unit cannot receive the maximum power value Pmax.

[0014] Wherein, the optical power values ​​of the N groups of received signals are collected, and the optical power values ​​of the received signals at the actual tracking point (x α ,y β ) best The specific steps to complete the self-calibration process of the optical tracking point are as follows:

[0015] In the device tracking mode, the self-calibration function of the optical tracking point is turned on, and the optical tracking point (x0, y0) is recorded in [P min -P max ] interval, statistically calculate the optical power value P(0,0) at the optical tracking point (x0, y0), and record the current optical power value P(0,0) into the array M1;

[0016] Step n*l displacements (n=1, l represents the displacement) of the x-axis of the optical tracking point, statistically calculate the optical power value P(0+n*l, 0) based on 3Σ at the tracking point (x0+n*l, y0), and record the current P(0+n*l, 0) in the array M1;

[0017] Compare the current power value P(0+n*l, 0) to see if it is less than the power threshold P that cannot communicate nocommu , if better than P nocommu , then continue to execute the second step above. If it is higher than P nocommu If it is smaller, proceed to step 4;

[0018] Step the x-axis of the optical tracking point by n*l pixels (n=-1, l represents the displacement), statistically calculate the optical power value P(0+n*l, 0) based on 3Σ at the tracking point (x0+n*l, y0), and record the current P(0+n*l, 0) in the array M1;

[0019] Compare the current power value P(0+n*l, 0) to see if it is less than the power threshold P that cannot communicate nocommu , if better than P nocommu , then continue to execute the fourth step above. If the ratio is P nocommu If it is smaller, proceed to step 6;

[0020] Find the maximum received power P in the array M1 of recorded optical powersbest The corresponding tracking point coordinates (x best , y0), recorded as the optimal tracking point on the X axis;

[0021] At the optimal tracking point on the X axis (x best , y0), continue to use the above method to find the optimal tracking point on the Y axis;

[0022] Find the maximum received power P in the recorded optical power array M2 best The corresponding tracking point coordinates (x best ,y best ), recorded as the optimal tracking point after self-calibration. From then on, the self-calibration process of optical tracking points is completed.

[0023] The specific steps of continuing to use the above method to find the optimal tracking point on the Y axis are:

[0024] The optical tracking point is stepped n*l times on the y axis (n=1, l represents the displacement), and the position of the tracking point (x best , y0+n*l) under the optical power value P(best, 0+n*l), and record the current P(best, 0+n*l) into the array M2;

[0025] Compare the current optical power value P(best, 0+n*l) to see if it is less than the power threshold P at which communication is impossible. nocommu , if better than P nocommu , then continue to execute the first step above. If nocommu If it is smaller, proceed to step 3.

[0026] The optical tracking point is stepped n*l times on the y-axis (n=-1, l represents the displacement), and the position of the tracking point (x best , the optical power value P(best, 0+n*l) under y0+n*l), and records the current P(best, 0+n*l) into the array M2.

[0027] The optical power value P(0,0) at the optical tracking point (x0,y0) is calculated by statistics using three times the standard deviation to calculate the optical power value P(0,0) of 3Σ at the optical tracking point (x0,y0).

[0028] Among them, the number of the light spot position detectors is one or two. When a beacon-free light scanning and capture system is adopted, one light spot position detector is adopted to detect the beacon light; when a scanning and capture system with secondary tracking of beacon light and signal light is adopted, two light spot position detectors are adopted to detect the beacon light and the signal light respectively.

[0029] The beacon-free optical scanning capture system is composed of a light spot tracking unit, a laser emission module, a light spot position detector, and a signal light receiving unit.

[0030] The present invention discloses a method for self-calibration of optical tracking points of a laser communication system, which realizes the self-adaptation of optical tracking points of a wireless laser communication system. For airborne and satellite-borne laser communication equipment with complex operating environments, it is inconvenient for debugging personnel to debug the optical tracking points on site. This method eliminates the tedious steps of manual on-site parameter adjustment. Different operating temperature environments, slight deformation of the equipment structure caused by vibration or temperature, different communication distances, different light spot states, etc. will affect the coordinates of the optical tracking points. The method described in this patent can make the entire optical tracking point calibration work fully automatically and adaptively calibrated under any operating environment conditions, thereby reducing labor costs and greatly improving the communication stability of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0032] Figure 1 It is a flowchart of the optical tracking point self-calibration method of the laser communication system according to the first embodiment of the present invention.

[0033] Figure 2 The first embodiment of the present invention collects N groups of optical power values ​​of the received signals, and uses a data statistical method to calculate the optical power values ​​at the actual tracking point (x α ,y β ) best The optimal value of the optical tracking point is shown in the figure, which is a specific step diagram to complete the self-calibration process of the optical tracking point.

[0034] Figure 3 This is a diagram of specific steps of continuing to use the above method to find the optimal tracking point on the Y-axis in the first embodiment of the present invention. DETAILED DESCRIPTION

[0035] Embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0036] First embodiment:

[0037] See also Figures 1 to 3 The present invention provides a laser communication system optical tracking point self-calibration method, comprising the following steps:

[0038] S1. First, perform optical debugging. By adjusting the spot tracking unit, adjust the received signal optical power value detected by the power detector of the signal light receiving unit to the maximum value P max .

[0039] S2. At this time, the light beam will pass through the beam splitter and hit the tracking detector at the other end, and the spot position at this time will be adjusted to the center of the spot position detector, and the center is the optical tracking point (x0, y0).

[0040] Specifically, first, optical debugging is performed. By adjusting the light spot tracking unit, the optical power value of the received signal detected by the power detector of the signal light receiving unit is adjusted to the maximum value Pmax. At the same time, the light beam emitted by the laboratory will pass through the beam splitter and hit the tracking detector at the other end. In order to facilitate later use, the light spot position at this time will ideally be adjusted to the center of the light spot position detector. The center coordinate position is (x0, y0), and (x0, y0) is called the optical tracking point of the beaconless light scanning capture system.

[0041] S3. Afterwards, the laser emitting module emits a laser beam, and the laser beam is received by the light spot position detector and the signal light receiving unit.

[0042] Specifically, the number of the spot position detectors is one or two. When a beacon-free optical scanning and capture system is adopted, one spot position detector is adopted to detect the beacon light; when a scanning and capture system with secondary tracking of beacon light plus signal light is adopted, two spot position detectors are adopted to detect the beacon light and the signal light respectively. After the two spot position detectors are adopted to detect the beacon light and the signal light respectively, the calibration of the optical tracking points also needs to be calibrated separately, wherein the optical tracking points include beacon light tracking points and signal light tracking points, and the beacon-free optical scanning and capture system is composed of a spot tracking unit, a laser emitting module, a spot position detector, and a signal light receiving unit.

[0043] S4. Splitting the laser beam received by the light spot position detector and the signal light receiving unit into two by means of the beam splitter.

[0044] S5, automatically adjust the position of the laser beam, so that the spot position follows the position adjustment of the laser beam, and the spot position is the actual tracking point (x α ,y β ).

[0045] Specifically, the optical tracking point (x0, y0) obtained in laboratory debugging will deviate from the optical tracking point in actual use, mainly manifested in: after the spot position detector detects the spot position and turns on the tracking function, when the spot tracking unit locks the spot position on the target surface (x0, y0) of the spot position detector, the signal light receiving unit cannot receive the maximum power value Pmax.

[0046] S6, collecting N groups of optical power values ​​of the received signals, and using a statistical method to calculate the optical power values ​​at the actual tracking point (x α ,y β ) best The optimal value of the optical tracking point is obtained to complete the self-calibration process of the optical tracking point.

[0047] Specifically, the optical power values ​​of N groups of received signals are collected, and the optical power values ​​of the received signals at the actual tracking point (x α ,y β ) best The specific steps to complete the self-calibration process of the optical tracking point are as follows:

[0048] S61, start the self-calibration function of the optical tracking point in the device tracking mode, record the optical tracking point (x0, y0) in [P min -P max ] interval, statistically calculate the optical power value P(0, 0) at the optical tracking point (x0, y0), and record the current optical power value P(0, 0) into the array M1.

[0049] Specifically, in the device tracking mode, the self-calibration function of the optical tracking point is turned on, and the optical tracking point (x0, y0) is recorded in [P min -P max ] interval, and calculate the optical power value P(0, 0) of 3Σ at the optical tracking point (x0, y0) using 3 times the standard deviation statistics, and record the current optical power value P(0, 0) into the array M1.

[0050] S62, stepping the x-axis of the optical tracking point by n*l displacements (n=1, l represents the displacement), statistically calculating the optical power value P(0+n*l, 0) based on 3Σ at the tracking point (x0+n*l, y0), and recording the current P(0+n*l, 0) into the array M1;

[0051] S63: Compare whether the current power value P(0+n*1,0) is less than the power threshold value P that cannot communicate. nocommu , if better than P nocommu , then continue to execute the second step above. If it is higher than Pnocommu If it is smaller, proceed to step 4;

[0052] S64, stepping the x-axis of the optical tracking point by n*l pixels (n=-1, l represents the displacement), statistically calculating the optical power value P(0+n*l, 0) based on 3Σ at the tracking point (x0+n*l, y0), and recording the current P(0+n*l, 0) into the array M1;

[0053] S65: Compare whether the current power value P(0+n*1,0) is less than the power threshold value P that cannot communicate. nocommu , if better than P nocommu , then continue to execute the fourth step above. If the ratio is P nocommu If it is smaller, proceed to step 6;

[0054] S66, find the maximum received power P in the array M1 of recorded optical powers best The corresponding tracking point coordinates (x best , y0), recorded as the optimal tracking point on the X axis;

[0055] S67, at the optimal tracking point on the X axis (x best , y0), continue to use the above method to find the optimal tracking point on the Y axis;

[0056] Specifically, the specific steps of continuing to use the above method to find the optimal tracking point on the Y axis are:

[0057] S671, the y-axis of the optical tracking point is stepped by n*l displacements (n=1, l represents the displacement amount), and the tracking point (x best , y0+n*l) under the optical power value P(best, 0+n*l), and record the current P(best, 0+n*l) into the array M2;

[0058] S672: Compare whether the current optical power value P(best, 0+n*l) is less than the power threshold value P at which communication is impossible. nocommu , if better than P nocommu , then continue to execute the first step above. If nocommu If it is smaller, proceed to step 3.

[0059] S673: The optical tracking point is stepped n*l times on the y-axis (n=-1, l represents the displacement), and the tracking point (x best , the optical power value P(best, 0+n*l) under y0+n*l), and records the current P(best, 0+n*l) into the array M2.

[0060] S68, find the maximum received power P in the recorded optical power array M2. best The corresponding tracking point coordinates (x best ,y best ), recorded as the optimal tracking point after self-calibration. From then on, the self-calibration process of optical tracking points is completed.

[0061] What is disclosed above is only one or more preferred embodiments of the present application, and cannot be used to limit the scope of rights of the present application. Ordinary technicians in this field can understand that all or part of the processes of implementing the above embodiments and equivalent changes made according to the claims of the present application are still within the scope covered by the present application.

Claims

1. A laser communication system optical tracking point self-calibration method, characterized in that: The following steps are involved: First, perform optical debugging. By adjusting the spot tracking unit, adjust the received signal optical power value detected by the power detector of the signal light receiving unit to the maximum value P max ; At this time, the light beam will pass through the beam splitter and hit the tracking detector at the other end, and the spot position at this time will be adjusted to the center of the spot position detector, and the center is the optical tracking point (x0, y0); Afterwards, the laser emitting module emits a laser beam, and the laser beam is received by the light spot position detector and the signal light receiving unit; Then the laser beam received by the light spot position detector and the signal light receiving unit is split into two by the beam splitter; Automatically adjust the position of the laser beam so that the spot position follows the position adjustment of the laser beam. The spot position is the actual tracking point (x α ,y β ); Collect N groups of optical power values ​​of the received signals, and use data statistics to calculate the optical power values ​​at the actual tracking point (x α ,y β ) best The optimal value of the optical tracking point is obtained to complete the self-calibration process of the optical tracking point.

2. The method for self-calibration of optical tracking points in a laser communication system according to claim 1, characterized in that: The optical tracking point (x0, y0) obtained by laboratory debugging will deviate from the optical tracking point in actual use, mainly manifested in that after the spot position detector detects the spot position and turns on the tracking function, when the spot tracking unit locks the spot position on the target surface (x0, y0) of the spot position detector, the signal light receiving unit cannot receive the maximum power value Pmax.

3. The method for self-calibration of optical tracking points in a laser communication system according to claim 1, characterized in that: The optical power values ​​of the received signals of N groups are collected, and the optical power values ​​of the received signals at the actual tracking point (x α ,y β ) best The specific steps to complete the self-calibration process of the optical tracking point are as follows: In the device tracking mode, the self-calibration function of the optical tracking point is turned on, and the optical tracking point (x0, y0) is recorded in [P min -P max ] interval, statistically calculate the optical power value P(0,0) at the optical tracking point (x0, y0), and record the current optical power value P(0,0) into the array M1; Step n*l displacements (n=1, l represents the displacement) of the x-axis of the optical tracking point, statistically calculate the optical power value P(0+n*l, 0) based on 3Σ at the tracking point (x0+n*l, y0), and record the current P(0+n*l, 0) in the array M1; Compare the current power value P(0+n*l, 0) to see if it is less than the power threshold P that cannot communicate nocommu , if better than P nocommu , then continue to execute the second step above. If it is higher than P nocommu If it is smaller, proceed to step 4; Step the x-axis of the optical tracking point by n*l pixels (n=-1, l represents the displacement), statistically calculate the optical power value P(0+n*l, 0) based on 3Σ at the tracking point (x0+n*l, y0), and record the current P(0+n*l, 0) in the array M1; Compare the current power value P(0+n*l, 0) to see if it is less than the power threshold P that cannot communicate nocommu , if better than P nocommu , then continue to execute the fourth step above. If the ratio is P nocommu If it is smaller, proceed to step 6; Find the maximum received power P in the array M1 of recorded optical powers best The corresponding tracking point coordinates (x best , y0), recorded as the optimal tracking point on the X axis; At the optimal tracking point on the X axis (x best , y0), continue to use the above method to find the optimal tracking point on the Y axis; Find the maximum received power P in the recorded optical power array M2 best The corresponding tracking point coordinates (x best ,y best ), recorded as the optimal tracking point after self-calibration. From then on, the self-calibration process of optical tracking points is completed.

4. The method for self-calibration of optical tracking points in a laser communication system according to claim 3, characterized in that: The specific steps of continuing to use the above method to find the optimal tracking point on the Y axis are: The optical tracking point is stepped n*l times on the y axis (n=1, l represents the displacement), and the position of the tracking point (x best , y0+n*l) under the optical power value P(best, 0+n*l), and record the current P(best, 0+n*l) into the array M2; Compare the current optical power value P(best, 0+n*l) to see if it is less than the power threshold P at which communication is impossible. nocommu , if better than P nocommu , then continue to execute the first step above. If nocommu If it is smaller, proceed to step 3. The optical tracking point is stepped n*l times on the y-axis (n=-1, l represents the displacement), and the position of the tracking point (x best , the optical power value P(best, 0+n*l) under y0+n*l), and records the current P(best, 0+n*l) into the array M2.

5. The method for self-calibration of optical tracking points in a laser communication system according to claim 3, characterized in that: The optical power value P(0,0) at the optical tracking point (x0,y0) is calculated by using three times the standard deviation to calculate the optical power value P(0,0) of 3Σ at the optical tracking point (x0,y0).

6. The method for self-calibration of optical tracking points in a laser communication system according to claim 1, characterized in that: The number of the light spot position detectors is one or two. When a beacon-free light scanning and capture system is used, one light spot position detector is used to detect the beacon light; when a scanning and capture system with secondary tracking of beacon light and signal light is used, two light spot position detectors are used to detect the beacon light and the signal light respectively.

7. The method for self-calibration of optical tracking points in a laser communication system according to claim 6, characterized in that: The beacon-free optical scanning capture system is composed of a light spot tracking unit, a laser emission module, a light spot position detector, and a signal light receiving unit.

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