Design Of CUDA Based BEIDOU Satellite Navigation Signal Simulation Algorithm And BEIDOU Software Receiver

Rapid development of Beidou satellite navigation system brings challenges to the research fields of Beidou terminal and related algorithm.The aim of this paper is to research the Beidou navigation signal simulation and Beidou software receiver,both of them has high research value.Beidou navigation signal simulation can provide verification environment to development of Beidou terminal and experimental data to research of related algorithm.And Beidou software receiver overcomes the shortcomings of hardware receiver,such as difficulty of upgrade,fixed parameters and low flexibility.It can be used to verify the navigation algorithm.The specific research contents are as follows:1.Completing the design of Beidou signal simulator.It includes two parts,AV1443 based hardware system and Beidu navigation signal simulation software.FPGA and DDR2 are used to realize read-write structure of hardware system,the read and write operations of DDR2 are controlled by FPGA.And simulation software is using heterogeneous structure of CPU and GPU,the graphic card can accelerate software running speed.2.Completing the algorithm of Beidou intermediate frequency(IF)signal simulation.On the basis of analysis of Beidou IF signal structure,Models of signal transmission and error correction are built;calculation of precise signal transmission delay is implemented.And Dynamic Doppler model is built to control code phase and carrier Doppler of generated signal in real-time.3.CUDA is used to improve the efficiency of serial signal simulation algorithm.After analysis of CUDA calculation model and register,signal simulation algorithm is parallelized and design of thread structure is completed.Some optimizations are also implemented to increase the algorithm obviously.4.Using local zero-padded sequence to overcome the sideeffect in signal acquisition which is caused by the presence of NH code.And FFT frequency domain analysis is used to realize two-dimensional searching of NH code phase and fine carrier frequency.5.On the basis of stable signal tracking,some methods are used to process the data,such as bit synchronization,NH code stripping,frame synchronization,etc.Finally,the positioning calculation is completed.