Design And Implementation Of GPS Intermediate Frequency Signal Simulator

GPS intermediate frequency signal simulator is the apparatus which can output the intermediate frequency signal modulated by GPS baseband spread spectrum signal. The output signal can be handled by RF module to simulate GPS signal, then provide the environment in which the GPS receiver can be researched, explored and tested. At the same time,it can be used in system GPS simulation to make sure that the test subsequence is right. It's very important applied in both civil and military fields.This article research the GPS intermediate frequency signal simulator based on software radio, the work has been done include:1.This article introduces the characteristics of the GPS signal, analyze the method to produce the multi-channel GPS intermediate frequency signal and a GPS intermediate frequency signal simulator realization model based on that software radio is achieved after comparative analyzing the realization structure.2.Research the method for increase the signal parameter refresh speed of GPS intermediate frequency signal simulator, estimate the pseudorange and relative speed between GPS satellite and GPS receiver with different model, and give some detailed analyze on some typical condition and the model should be used by GPS intermediate frequency signal simulator.3.Next a more detailed analysis is made on the GPS intermediate frequency signal simulator in the carrier number controlled oscillator and code number controlled oscillator to conduct, and the key parameters of selection were mainly studied.4.An ARM and FPGA system design program is made, and the system structure division in the design of hardware and software is carried out, then the hardware development platform and the corresponding software are development, the system test results show that the GPS intermediate frequency signal simulator works well.