Signal Simulation And Software Receiver Development For GLONASS Satellite Navigation

With the wide application and rapid development of global satellite navigation system,the simulation algorithms and receiving terminal design of satellite navigation signals face more challenges.GLONASS satellite navigation system as the world's second largest navigation system,it has unique signal system and modulation,so that it has its own advantages,and has strong complementarity with other systems.This paper studies the GLONASS satellite navigation intermediate frequency(IF)signal simulation algorithm,designs a GLONASS satellite navigation simulation source,and develops a GLONASS software receiver.1.A system scheme of GLONASS IF signal simulation source is designed.It consists of two parts: GLONASS IF signal software simulation module based on C ++ Platform and IF signal broadcast module based on microwave vector signal generator.The software module generates IF digital signal data file based on the IF signal model,the hardware module realizes the continuous broadcast,interpolation and filtering of the signal through the FPGA,converts the digital signal into analog signal by DAC,and broadcasts the signal to L1 frequency by RF modulation.2.An algorithm of GLONASS IF signal simulation is achieved.Based on the analysis of GLONASS IF signal structure,a signal propagation model and an error correction model are established.The generation of pseudo-range adopts the method of iterative calculation and interpolation,this method can get accurate pseudo-range and delay at any time.Combined with the dynamic Doppler model,pseudo-random code,navigation message and carrier signal are generated with accurate time-delay and Doppler shift.According to the mathematical model of GLONASS IF signal,the GLONASS IF signal is simulated,and the signal file is generated.3.A GLONASS software receiver is developed.The receiver completes the capture and tracking of visible satellites from GLONASS satellite navigation signals,demodulates the satellite ephemeris,pseudo-range measurements,and calculates user's three-dimensional position,velocity and time information,outputs the results.It can be used to verify the correctness of the simulated signal.