Research And Design Of Microwave Radar Simulator For Rendezvous And Docking

Rendezvous and docking radar is an indispensable measurement sensor in the process of rendezvous and docking,which plays a vital role in the docking process.Rendezvous and docking transponder signal simulator is to build in the laboratory environment closed-loop rendezvous and docking simulation scenarios,one of the special ground detection devices designed for the overall performance test of radar.on the basis of the overall research and deign of the medium frequency radar signal simulator,this paper focuses on improving the instantaneous simulation accuracy and signal synchronization accuracy of the simulator.Firstly,this paper studies the basic working principle of rendezvous and docking radar system,and introduces the transmission protocol of measuring signal.Then the relative motion process during rendezvous and docking is analyzed.On this basis,the corresponding signal simulator design scheme is designed,including the analog signal transmitting channel,receiving channel,upper computer data intersection and so on.Secondly in order to achieve a more realistic simulation of docking process signals,this paper analyzes the relative motion trajectories of spacecraft,and deduces the construction of uplink data link and downlink data link simulation information under relatively static and relative dynamics.And in view of the shortcomings in traditional continuous wave signal simulation instantaneous low accuracy,high speed variable time delay control scheme is presented to improve the signal simulation accuracy under the two-way ranging system,the clock is poor control precision at the same time to ensure the data channel with low error rate,and then the error in the process of simulation is analyzed,the main error term is optimized.After,this paper studies the signal receiving module,considering the actual situation equipment input signal is being measured signal-to-noise ratio change,we design a simple and effective to facilitate the FPGA implementation of adaptive threshold detection method,for the carrier and pseudo-code tracking using the frequency lock loop auxiliary phase lock loop model auxiliary pn code tracking loop and carrier tracking loop design,ensure the carrier and code tracking speed and precision of the pn,are introduced in order to improve the precision of pseudo range and carrier phase measurement,use of the advantages of the FPGA high-speed parallel computing,and improved pseudo range measurement algorithm,improve the pseudo range measurement precision and clock difference calculation accuracy.Finally,the design scheme is combined with the simulation test results of the signal simulator based on FPGA.Then,joint upper machine commissioning test,verify the simulatorin a double system test clock skew,right after the distance and speed calculation,through a simple motion model of the simulator has carried on the static test and dynamic test,verify the actual performance is improved and optimized algorithm,and implements the simulator of the corresponding technical index requirements.