Design And Implementation Of Satellite-based ADS-B Signal Simulation And Test Software

Automatic dependent surveillance-broadcast(ADS-B)is widely used in flight tracking and air traffic control(ATM).Compared with the traditional land-based ADS-B system,the satellite-based ADS-B system has the advantages of wider coverage and no limitation of terrain.Therefore,countries around the world are vigorously promoting and developing satellite-based ADS-B technology.However,the satellite-based ADS-B signal has such problems as low signal power,large Doppler frequency shift and easy overlapping.According to the characteristics of the satellite-based ADS-B signal,the paper simulates satellite-based ADS-B signal and tests satellite-based ADS-B receiver,which play an important role in the design and development of satellite-based ADS-B receiver.A satellite-based ADS-B signal simulation and testing software is designed,which can simulate the satellite-based ADS-B signal transmitted by multiple targets,and complete the test of the satellite-based ADS-B receiver.Firstly,the multiple antenna low-orbit satellite is modeled and the target's track in the satellite coverage area is simulated.The Doppler frequency shift is obtained by calculating the radial velocity of the target relative to the satellite,and the signal power is obtained by the satellite communication link formula.The overlapping of signals is simulated by simulating the stochastic characteristics of message update time.At the same time,the satellite coverage area and target track are displayed.Secondly,ADS-B messages are generated by encoding the position,speed and other information in the track data.The satellite-based ADS-B special message data including message,power,Doppler frequency shift and overlapping information is sent to the lower computer,which generates satellite-based ADS-B analog signal in real time according to the information of the special message.Finally,build a test platform to send the satellite-based ADS-B analog signal to the receiver under test.By comparing and analyzing the transmitted data and the receiver return data,the received rate of the receiver is calculated,and the receiver performance is tested.