Research On Direct Acquisition Technology Of GPS P Code

GPS P code with the characteristics of high rate,long cycle,anti-interference ability,can provide users with sophisticated positioning and timing services.And its provision of the variety of services is to capture the P code successfully.So how tocapture P code more quickly and accurately has become one of the key issues that domestic and foreign scholars.Based on the reading of a large number of literatures,the shortcomings of the existing P code acquisition methods are analyzed in the paper.Aiming at the problems of the existingalgorithm,the direct capture algorithm of P code is deeply analyzed and studied.And anew P code capture algorithm is put forward.Then the newcapture algorithm is optimized.The specific work done by the article includes:(1)The GPS software receiver and GPS signal structure are introduced in detail,and the C / A code and P code are successfully simulated.The acquisition principle of GPS signal is analyzed and the estimation of the search range is completed.The traditional P-code indirect capture algorithm is introduced,and the shortcoming of the indirect capture algorithm is pointed out by the simulation experiment.The significance of the direct capture algorithm is described.(2)In this paper,the principle of P-code direct capture algorithm based on FFT is introduced in detail,and the model establishment and matlab simulation analysis of the algorithm are successfully completed.And it is compared with the parallel execution algorithm in terms of the amount of computation.The quantization of the extended replication overlay acquisition algorithm and the mean acquisition algorithm is successfully completed.And the capture results of the two algorithms are simulated and analyzed.The limitation of the two algorithms is pointed out too.(3)A new method of direct acquisition of P code based on mean algorithm and extended replication overlay acquisition algorithm is proposed.The principle of the new algorithm is given,the feasibility of the new algorithm is demonstrated,and the capture results of the new algorithm are analyzed by matlab simulation,which show that the new capture algorithm is effective to improve the speed and accuracy of the capture.The new method is further optimized,and the optimization algorithm is completed and the simulation results show that the optimization effect is achieved.(4)The efficiency of the algorithm is analyzed from three aspects: algorithm complexity,acquisition time and acquisition precision,which further validates the excellent capture effect ofoptimized new algorithm.