Research On Transmitting And Receiving Coaxial Pyramid Calibration Technology In Space Laser Communication

In the face of rapid growth in the demand for space information,space laser communication systems with great potential in communications have received increasing attention.Satellite laser communication has the characteristics of high transmission rate,large bandwidth capacity,and strong confidentiality.At the same time,communication terminals also have the advantages of light weight,low power consumption,and small size.Under the premise of ensuring communication capabilities,they also comply with the miniaturization of satellites.Lightweight development trend.The design of the optical antenna system of the communication terminal has an important influence on the quality of communication and the overall size and weight of the terminal.The subject of this article selects the optical antenna system for receiving and transmitting the coaxial mode,and uses the corner cube prism as a feedback device,which can effectively reduce the volume and weight of the optical antenna system.The corner cube prism has an excellent retroreflective property,but inevitably there is an irregular reflection spot and a dihedral angle error caused by the processing.At present,domestic diagonal cones are used in the research work of high-precision optical inspection systems,and there is a lack of discussion on this issue.In addition,the backend processing system for detecting the data of the four-quadrant detector in the transceiver coaxial system has the requirements of high efficiency,flexibility,low cost,and strong real-time performance,and the parallel computing capability of the FPGA is very suitable for the calibration of this pyramid.System,so this paper chooses FPGAbased digital system for back-end circuit design.This article has completed a study of the coaxial coaxial pyramid calibration technology.:(1)Calculate the optical principle of transponder coaxial prism calibration and carry out simulations.Many conclusions with reference value are obtained.Using matrix optics and vector optics,a retro-reflection model of cube corner prisms was established.Combined with the principle of four-quadrant detectors,Matlab simulation was used.Analysing the centroid shift simulation results can qualitatively determine the general direction of the center of mass offset by the positive and negative relationships between the three dihedral angle errors of the corner cube.When the dihedral angle error is negative,the deviation of the reflected spot is smaller.At the same time,in the high-precision detection,the model is used to eliminate the offset and the detection accuracy can reach 0.1 ?m.(2)The working principle and positioning principle of the four-quadrant detector for key detection devices are studied,and a suitable positioning detection algorithm is selected.The four-quadrant detector's photovoltaic principle supports working in photovoltaic mode to better suit the system.The detector positioning principle combines the uniform distribution of the spot energy and the Gaussian distribution model,which supplements the theoretical basis for the first chapter of the algorithm.(3)Completed the hardware design of the receiving and receiving coaxial pyramid calibration system.This part of the work includes the selection of electronic devices,the design of the detector amplifier circuit,the design of the FPGA minimum system,FPGA power circuit and peripheral configuration circuit,AD7606 acquisition circuit and power supply circuit,and RS485 serial port design.(4)Completed the software design of the detection system based on the FPGA platform.Using the design concept of the state machine,the AD acquisition driver,asynchronous FIFO,and RS485 transmission were designed using Verilog hardware description language.And compile and debug work in Quartus II software,and write the waveform file,Testbench.The simulation of control design was simulated by Modelsim software,and the correctness of the program was verified.