Research On Time Delay Technologies Of Satellite Channel Simulator

As the inter-satellite or satellite-ground precision ranging and specific implementation platform,Spaceborne communications measuring load plays an important role in the BD navigation satellite system,test its performance in the external environment is very important.Satellite Channel Simulator can provide reliable and stable test environment for the Spaceborne communications measuring load performance testing,greatly reducing the test cycle and testing costs.How to ensure that satellite channel simulator doppler simulation accuracy and delay simulation accuracy is the key technology of Satellite Channel Simulator.In this paper,the satellite channel simulator key technologies research directions has a good-looking,content and results have some guiding significance of a satellite simulator's research and implementation.The main content of this paper can be summarized as the following aspects:1.We studied the satellite signal generation principle,the impact of spatial channel characteristics of the satellite signal.Propose an overall plan of satellite channel simulator,Analysis and design implementation plan of the respective channel simulator modules.Forcus the research priorities on the doppler simulation and delay control of the Satellite Channel Simulator.2.For the key technical problems of the dynamic doppler simulation in the Satellite channel simulator.Analysis the causes of the doppler shift,Propose a high dynamic doppler simulation method of satellite channel simulator with 3 order DDS.Test the feasibility of doppler simulation method under different scenarios.3.For the key technical problems of the dynamic time delay control in the Satellite channel simulator.Proposed a overall delay scheme of two parts:wide range of control and precision delay control.Use storage fast read and write method to solve the wide range problem of delay;Propose Fractional delay filtering method to solve the high precision delay problem of channel simulation;Proposes a method using polynomial fitting to simplify fractional delay filter coefficient update calculation process,in order to solve the problem of high dynamic time delay problem.4.The time delay effect of Satellite Channel Simulator's fractional delay filter is simulated.And through further analysis of the relationship between the delay precision of fractional delay filter with a variety of different influencing factors,and summed up the relationship table.And proposed a quick method of fractional delay filter design with finding the relationship table,this method has important significance on fractional delay filter design optimization and saving hardware resources.