Research And Implementation Of Simulation About Satellites' Navigation Signal

With the development of Satellite navigation Service, Satellite signal simulator is a powerful tool to test Reciver and it is very significant to carry out related research. Satellite signal simulator represent the level of the development and application of a national satellite navigation.It is a key instrument of application in satellite navigation system and various Reciver, also, authority pays high attention to simulator.This paper's aim is regular navigation reciver's request Studys,including algorithms,especially about the designs and realizations of the unit of control and simulation and the unit of signal generator.Main points of this paper are:First, The introduction of satellite navigation simulator and working principles macroscopically describe the overall architecture of satellite navigation simulator; A deep Study about mathematical model of satellite navigation and simulator realized algorithm,composing: satellite's clock correction,ionized layer delay, tropospheric delay,satellite's orbit calculation,judgment about the satellite's visibility,Doppler shift and pseudo-range's calculation, etc; Giving a fitting algorithm based precise ephemeris about simulator ephemeris recursion.Seconds According to foregoing theory about simulator's mathematic model and the state of existing engeering level, the simulator and control unit of satellite navigation simulator is separated to 9 modules, including: human-computer interaction interface, parameter setting mode,the satellite's data simulation,propagational environment's simulation,parameter calculation and navigational message generation, communicational control and data storage.Describe each module of the software implementation process and the main function in detail.It focus on the structure of navigational code and calculation about each parameter.Finally, complete the whole design and accomplishment about the software of this simulator.And then, we research GPS IF signal generation algorithm and give each module's theory and designing scheme, including the design of the carrier NCO, the design of pseudo-code, the design of C / A code generation, shaping filter, interpolation filter and the BPSK modulation of carrier signal.As the simulated target is digital IF signal, use Xilinx's System generator to build the model of signal generation algorithm and achieve intermediate frequency signal simulation and hardware implementation.Last but not least, give a detailed verification and testing program, including the algorithm simulational test, communicational test, simulational test about signal generation unit and the test of actual hardware. Finally, propose a system-level testing program involving the high-speed ADC directly sample generated GPS IF signal into the mass storage module,and then import the saved data into the software receiver to analyze position testing and validation. According to Baseband signal analysis and positioning test about this design,it is verified that the GPS signal simulator can generate the specified signal and meet the requirements of satellite navigation simulator...