Research On GNSS Signal Simulation Technology Based On Software-Defined Radio

GNSS(Global Navigation Satellite System)signal simulation technology is of great significance for the test of satellite navigation terminal and verification of new signal system.At the same time,higher and more complex requirements are proposed with unceasing establishment of GNSS system and the emergence of new signal system.While,the development of software radio technology and related hardware equipment provides an effective way to solve this problem.Based on the idea and theory of software radio,this paper studies the GNSS signal simulation technology.Firstly,the basic theory of GNSS signal simulation is introduced,which has analyzed the structure of GNSS as well as the components and characteristics of GNSS signal at the macro level.The important role of GNSS signal in the system is clarified.Based on this,The Architecture of GNSS signal Simulation System is designed.Then the requirements of the simulation of GNSS signal is confirmed by designing the architecture of GNSS system,studying the simulation of GNSS signals on two planes: the information layer and the signal layer.The simulation process of information layer and signal layer is analyzed,and the simulation model of information layer is established that has tested the precision of simulation.The carrier generation algorithm,pseudo-code generation algorithm,signal modulation algorithm,key parameters in signal processing is designed,at the same time,the process of GNSS signal generation is clarified,and the main algorithm module and system interface is designed using Software Defined Radio structure.After the modeling and analysis of the information layer and the signal layer,the GNSS signal simulation system is designed and implemented in combination with the basic thought of software radio,and the architecture design of GNSS data simulation system,digital intermediate frequency signal processing system and RF signal generation system is completed.As well as the interface between the each system,the design and selection of hardware development platform.The design of the whole system is completed on the basis of the above design.This process fully embodies the technical features of software such as high versatility,high modularity,high flexibility and programmable reconfiguration,and enhances the versatility and reusability of the designed system.Finally,the GNSS signal simulation system is designed and simulated,and the performance of GNSS signal simulation is verified by positioning test and signal test,to verify the rationality of GNSS simulation system.