High Dynamic GPS Satellite Signal Simulator Software Research

The GPS satellite signal simulator is a kind of can produce high precision sta ndard GPS satellite navigation signal simulation signal source, based on the backgro und ofthe development of GPS satellite signal simulator software, the key proble m focuses on the software requirements and the development process of.According to the USA GPS satellite navigation system development, discusse s the corresponding GPS satellite signalsimulator software navigation. According to theapplication demand characteristics oftypical GPS signal and the typical GPS sate llite signal simulator, discussion is made on the basic principle of GPS satellite sig nalsimulator, then according to the softwareengineering analysis method for software requirement and design mode of the typicalideas "adapter pattern(Adapter)" and "sin glemode(Singleton)" PC software architecture design, the design will be a simulatio n process is regarded as a "project",the backtracking and development mechanism si mulator software simulation data.According to the characteristic of GPS system, ac cording to the requirements ofsimulator on the properties of pseudo random cod e design of embedded softwaremodule based on FPGA and DSP, Cyclone III series o f FPGA TI 6000 series DSP chip and Altera, propose and design code NCO digital l ogic and the control logic of DDSbased, completed part of the software code, verifi cation the correctness andrationality of design software needs. The. The round shape d cone projection method,the problem of coordinate systems on the satellite signal simulator is the most commonly used, algorithm, established the spatial coordinate t ransformation to theprojection model, validate the ECEF coordinates to latitude longi tude coordinatesused in the simulator software. Based o. Based on the time system u sedby GPS,established the conversion time of the UTC to GPS time model. This p aper presentsthe error model of GPS satellite signal simulator software, and based o n thecharacteristics of signal simulator research scope and methods of using the mod el.According to the Doppler frequency offset, the radial variable trajectory model wi thacceleration, jerk, calculate the influence on the Doppler shift on the dynamic sate llite signal, the RF signal and the signal model of the motion locus based on themo del,the use of distance difference calculation of phase difference to realize high dyn amic simulation.Use this function can make the high dynamic precsion to 1/322.