Research And Implementation Of Navigation Signal Simulator

Satellite navigation signal simulator can accurately simulate the navigation signalsreceived by the receiver in the carrier according to the carrier’s motion status. The simulatorcan be used to test the capability of acquiring, tracking and precision of the receiver which ismore important for the high dynamic receiver. Concerning the application ofhardware-in-the-loop (HIL) simulation system, the architecture of the platform, mathematicalmodel, method of simulation and so on are studied.Firstly, the current domestic and international development status and trends of thesatellite navigation signal simulator are introduced on the basis of the growth of variousnavigation satellite systems and the signal systems. Based on the satellite signal structure,properties and signal model of GPS navigation signal simulator, the overall architecture of thesatellite navigation signal simulator is presented. The function structures of the hardware andsoftware part, working principle and implementation plan are detailedly illustrated in thispaper.Then the state parameter calculation method of the signal simulator are analyzed and thecarrier’s attitude simulation technology is seriously studied to establish a carrier attitudemodel. The model can provide the visibility judgment algorithms of the satellite under carrierattitude. The feasibility of which is validated qualitatively by mathematical simulation. Andthe simulation technical scheme of the antenna pattern is given.Afterwards, the method for frequency synthesizing is studied and based on theimplementation principle of the carrier and code NCO, the multistage DDS model isintroduced. And then the calculation expression of the time-variant frequency word ispresented. Through successful simulations in multiple scenes, it’s good performance underhigh dynamic condition is taken on. Finally the hardware of the simulator is completed, accomplishing the synchronousdesign of the PCI interface and the fiber module. After navigation signal quality andperformance tests, the simulator’s ability of HIL is verified.