Research On Tracking Technology Of High Sensitivity BeiDou Receiver

After decades of development,satellite navigation has become the most widely used locating technology,which is of great significance for the development of national economy and military strategy.Meanwhile,BeiDou system has entered its third step of the layout program,while in 2020 it is expected to achieve the global satellite positioning service.Firstly,the influence of the parameters of satellite tracking loop on tracking performance is analyzed.In this paper,the modulation mode and structure of the Beidou B1 I frequency signal are introduced fully.The paper studies the structure of each component of the loop,verifies the effect of loop parameters on tracking performance.The relationship between loop parameters and loop tracking steady-state error is established,a feasible scheme is proposed to improve the tracking performance of the tracking loop,the dynamic relationship between the selection of the loop parameters and the positioning performance of the receiver is verified on the embedded verification platform.Secondly,further research on the integration time to enhance loop performance has been taken.An improved histogram of bit synchronization method was put forward for BeiDou D1 navigation message,this method could quickly achieve bit sync based on histogram and NH code.A coherent integration method that compatible with BeiDou and GPS was put forward,this method could flexible adjust integration time based on bit sync.Completed the coherent integration method based on FPGA and verified the method to enhance tracking the weak signal performance.Thirdly,the paper focuses on the analysis of the relationship between the dynamic stress and the tracking accuracy of the tracking loop.The effect of thermal noise on the performance of KF tracking loop is analyzed,and the filter carrier tracking loop is further simplified.The correlation value is used as the input of the measurement to realize the adaptive KF and EKF carrier tracking loop model.The method of tracking loop performance advantages has been tested in the hardware platform which simulate the scene of weak signals and high dynamic signals.Finally,the system verification platform was designed based on FPGA and DSP.The FPGA mainly parallel process multiple channels baseband data,and DSP mainly complete navigation algorithm and other complex operation.This framework is mainstream of receiver platform,it provides the test platform for further research about high performance receiver.