Acquisition And Tracking Research Based On Beidou Signal Of Low Complexity

BeiDou Navigation Satellite System(BDS)is our own developing and building system with independent intellectual property rights of the global satellite navigation and positioning system,even in China and the world which related applications has produced great value.With the growth of satellite navigation application requirements and the requirement of fast acquisition,the complexity of acquisition and tracking with Beidou signal has become a key research direction of satellite receivers.At present,the acquisition sequence of parallel code phase based on discrete Fourier transform is used to do the Beidou satellite acquisition and tracking phase.Compared with the time domain serial acquisition,the algorithm has saved a lot of computation.But in order to quickly locate and continue to reduce the hardware consumption of satellite receivers,we also need to continue to find the algorithm with lower algorithm complexity to acquisition traces to achieve this goal.In this thesis,the problem of high accuracy and high computational complexity for acquisition and tracking with Beidou signal is studied from the following aspects:Firstly,the structure of Beidou satellite signal is introduced.The commonly used acquisition and tracking method are analyzed.The acquisition algorithm of parallel code phase based on discrete Fourier transform is simulated and the signal is captured and traced successfully.Secondly,in the use of parallel code phase acquisition on the basis of the average correlation method,the signal sampling points into an integer power of 2,so as to change the DFT to FFT,greatly reduce the amount of computing.A local code quadratic sampling method is proposed to achieve better performance while averaging the reduced computational complexity.In this thesis,the method is simulated and the signal is captured successfully,and the acquisition algorithm based on the discrete code phase based on discrete Fourier transform is compared with the performance and computation.Thirdly,through the analysis of the satellite signal structure and the sparseness of the satellite navigation signal,the sparse Fourier transform is introduced,and some modifications are made according to the characteristics of the satellite signal.A simplified scheme based on sparse Fourier transform is proposed.The filtering method of the leaf transform reduces the computational complexity of the algorithm in the case of loss of partial performance.In this thesis,the method is simulated and the signal is successfully captured and compared with the previous performance algorithm based on the improved average correlation algorithm.Fourthly,the ground differential station is introduced to discuss the influence of ground differential station auxiliary data on the complexity of the whole tracing phase.By calculating the auxiliary data,the range of the estimated value and the frequency error value of the Doppler shift can be obtained,which reduces the frequency search range and reduces the computational complexity of the search process at the frequency in the acquisition process.It also improves the complexity of the sparse Fourier transform mentioned above by comparing the estimated value and the search range of the chip phase into the acquisition algorithm based on the sparse Fourier transform by calculating the auxiliary data,Thereby reducing the amount of computing the entire algorithm.In the process of receiver design and implementation,the low complexity of the acquisition and tracking algorithm can reduce the cost of hardware resources to achieve fast and reliable acquisition of the signal tracking,so as to achieve the acquisition and tracking tracing fast and accurate tracking requirements.