CN-119834889-B - Optical axis control device and method for space laser communication

CN119834889BCN 119834889 BCN119834889 BCN 119834889BCN-119834889-B

Abstract

The invention provides a space laser communication optical axis control device and a space laser communication optical axis control method, wherein a photoelectric detector is matched with a quick reflector 1 by utilizing a first-stage fine tracking loop, a nutation assembly is matched with a quick reflector 2 by utilizing a second-stage fine tracking loop, and meanwhile, the tracking zero position of the first-stage fine tracking loop is corrected according to the offset of the second-stage quick reflector. The invention is applied to space laser communication, and the cooperation of the two-stage fine tracking loop enables the beam control system to have the advantage of inhibiting beam jitter caused by high-frequency and strong vibration, and has the advantage of compensating the deviation of a communication optical axis and a tracking optical axis in real time.

Inventors

LI TAI
HOU XIA
GAO MIN
LI JIAWEI
HU QIONG
HE HUI
TIAN LINLIN

Assignees

中国科学院上海光学精密机械研究所

Dates

Publication Date: 20260512
Application Date: 20241219

Claims (2)

1. The control method of the space laser communication optical axis control device comprises a first-stage fine tracking loop, a second-stage fine tracking loop and a signal processing and control board card; The first-stage fine tracking loop comprises a beam splitter which is used for receiving signal light after being reflected by a first quick reflector, and converging the signal light on a first photoelectric detector through a first lens group to form a light spot 1 after being reflected by the beam splitter; The second-stage fine tracking loop comprises a beam splitter, a second rapid reflector, a second lens group, a nutation assembly, a second optical fiber and a second photoelectric detector, wherein the signal light is reflected by the first rapid reflector and then reaches the beam splitter, is transmitted by the beam splitter, is converged into a light spot 2 on the nutation assembly through the second rapid reflector, is spatially coupled into the optical fiber, and is partially transmitted into the second photoelectric detector through the optical fiber beam splitter; The signal processing and control board card is respectively connected with the first quick reflector, the first photoelectric detector, the second quick reflector, the nutation assembly and the second photoelectric detector in an electric signal manner; Setting initial zero positions of light spots on the first photoelectric detector and the second photoelectric detector and initial zero position driving voltage values of the first quick reflector and the second quick reflector by adjusting positions of the spectroscope, the first photoelectric detector, the second quick reflector and the nutation assembly; the driving voltage values are output by the signal processing and control panel card, and the light spot positions are processed and analyzed by the signal processing and control panel card, and the method is characterized by comprising the following steps: s1, determining initial zero position of a light spot 1 on a first photoelectric detector and initial zero position driving voltage values of a first quick reflector; s2, after the signal light is reflected by the first quick reflector and the spectroscope, converging the signal light into a light spot 1 on the first photoelectric detector through the first lens group, acquiring the current position of the light spot 1 by a signal processing and control board card, and calculating the position deviation of the light spot 1 according to the initial zero position of the light spot 1 on the first photoelectric detector; S3, according to the position deviation amount of the light spot 1 obtained in the step S2, adjusting a first quick reflector to enable the position of the light spot 1 to be converged at an initial zero position of the light spot 1; S4, controlling the nutation assembly to swing according to a specific track, wherein the swing track is circular or cross-shaped; S5, the signal light is reflected by the first quick reflector and reaches the spectroscope, the signal light is transmitted by the spectroscope and is converged into a light spot 2 on the nutation assembly through the second lens group, and then part of the light enters the second photoelectric detector through the optical fiber beam splitter, the current position of the light spot 2 is obtained by the signal processing and control board card, and the position deviation of the light spot 2 is calculated according to the initial zero position of the light spot 2 on the nutation assembly; S6, adjusting a second quick reflector according to the position deviation amount of the light spot 2 obtained in the step S5, so that the position of the light spot 2 is converged to an initial zero position of the light spot 2; S7, sliding statistics is carried out on the average value of the driving voltage of the second quick reflector, the deviation between the average value of the driving voltage of the second quick reflector and the initial zero driving voltage value of the second quick reflector is calculated, and when the deviation is larger than a set threshold value, the zero value of the light spot 1 on the first photoelectric detector is corrected; S8, executing the steps S2-S3 again, and enabling the position of the light spot 1 to be converged to the zero position value after the correction of the light spot 1 until the whole working flow is ended.
2. The method according to claim 1, wherein the step S7 is performed to calculate the deviation between the average value of the driving voltage of the second fast mirror and the initial zero driving voltage of the second fast mirror The formula is as follows: In the formula, The second fast mirror X-axis drive voltage average calculated for the nth slip, The average value of the second fast mirror Y-axis driving voltage calculated for the nth slip, For the initial zero drive voltage value of the X-axis of the second fast mirror, Initial zero driving voltage value for the Y axis of the second quick reflector; In the step S7, the zero value of the light spot 1 on the first photodetector is corrected, and the formula is as follows: + Wherein A is a conversion matrix from the deviation of the driving voltage of the second quick reflector to the zero correction quantity of the light spot 1, xt 1(m-1) is the zero X-axis coordinate value of the light spot 1 after m-1 times of correction, yt 1(m-1) is the zero Y-axis coordinate value of the light spot 1 after m-1 times of correction, xt 1 is the zero X-axis coordinate value of the light spot 1 after m-1 times of correction, and Yt 1 is the zero Y-axis coordinate value of the light spot 1 after m-1 times of correction.

Description

Optical axis control device and method for space laser communication Technical Field The invention belongs to the technical field of optical equipment, and particularly relates to a device and a method for controlling a space laser communication optical axis. Background The satellite internet construction is taken as a new foundation in China, the satellite constellation networking is steadily promoted, and an important ring in the constellation networking is the establishment and maintenance of inter-satellite communication links. The inter-satellite communication link has two implementation modes of microwave communication and laser communication, and compared with the microwave communication, the laser communication has the unique advantages of low power consumption, high speed, small volume, no frequency spectrum resource limitation and good confidentiality. The laser communication link will become an integral part of the satellite constellation. In order to realize inter-satellite laser communication, a link is established and maintained by a scanning, capturing and tracking device, namely, space light is efficiently coupled into an optical fiber, and then optical signals are modulated and demodulated. The laser communication link is affected by satellite platform micro-vibration and thermal deformation, resulting in reduced coupling efficiency of spatial light to the fiber. The existing conventional solution uses a single-stage fine tracking device to realize the control of an optical axis, but the design is limited by the limited bandwidth of a fine tracking loop, the coupling efficiency of space light to an optical fiber is reduced under the strong space vibration environment, and in addition, the thermal deformation of an optical system is periodically influenced by the space thermal environment due to the design that the tracking axis and a communication axis are separated, so that the problem that the tracking axis and the communication axis are not coaxial exists in the long-time maintenance process of a communication link is solved. To solve the problem of limited bandwidth of the single-stage fine tracking loop, High-speed free-space optical communication using standard fiber communication components without optical amplification[J].Advanced Photonics Nexus, 2023, 2(6):065001.DOI:10.1117/1.APN.2.6.065001 A two-stage fine tracking device is described, but this design does not solve the problem of the tracking optical axis not being coaxial with the communication optical axis due to thermal deformation of the optical system. Patent CN114389683B, issued by Beijing remote sensing equipment research institute at 03 and 29 in 2024, describes a method for automatically correcting an optimal tracking point of a communication detector on orbit, but the method can not solve the problem of separation of a tracking axis and a communication axis, and the method actively causes the reduction of signal optical coupling power in a scanning process, so that the risk of a communication link terminal is increased. Disclosure of Invention In order to solve the problems in the prior art, the invention provides a space laser communication optical axis control device, wherein a photoelectric detector is matched with a quick reflector 1 by using a first-stage fine tracking loop, a nutation assembly is matched with the quick reflector by using a second-stage fine tracking loop, and the tracking zero position of the first-stage fine tracking loop is corrected according to the offset of the second-stage quick reflector. The invention is applied to space laser communication, and the cooperation of the two-stage fine tracking loop enables the beam control system to have the advantage of inhibiting beam jitter caused by high-frequency and strong vibration, and has the advantage of compensating the deviation of a communication optical axis and a tracking optical axis in real time. The technical scheme of the invention is as follows: On one hand, the invention provides a space laser communication optical axis control device, which is characterized by comprising a first-stage fine tracking loop, a second-stage fine tracking loop and a signal processing and control board card; The first-stage fine tracking loop comprises a beam splitter which is used for receiving signal light after being reflected by a first quick reflector, and converging the signal light on a first photoelectric detector through a first lens group to form a light spot 1 after being reflected by the beam splitter; The second-stage fine tracking loop comprises a beam splitter, a second rapid reflector, a second lens group, a nutation assembly, a second optical fiber and a second photoelectric detector, wherein the signal light is reflected by the first rapid reflector and then reaches the beam splitter, is transmitted by the beam splitter, is converged into a light spot 2 on the nutation assembly through the second rapid reflector, is spatially coupled into t