Gps Signals And Navigation Data Processing A Number Of Issues

The first part of this paper reviews GPS development and application in many fields and gives the analysis of GPS measurement model and the main error sources in detail.The second part of this paper study the tracking errors due to multipath considered autocorrelation sidelobe in GPS and also the effect of different early-late spacing .Based on noncoherent DLL and arctan carrier PLL, the curves of tracking errors in general forms are given after a series of computing and simulation.It is shown that tracking errors are different in different regions; autocorrelation sidelobe affects the code phase and carrier phase tracking errors of the longer time reative multipath delay ;a smaller early-late spacing can reduce the tracking errors both of code phase and of carrier phase.It is different from each other in mathematical sign.The third part of this paper discusses the least square and extended kalman filter algorithm.First of all, the model of the least square and extended kalman filter algorithm was described in detail . Secondly , both algorithms were processed using raw data for GPS Navigation solution. It is shown that the navigatio solution using extended kalman filter is better than the least square algorithm in many aspects including stabilization,precision and availability.The fourth part of this paper discusses the WADGPS and studys the data processing of the WADGPS, of which satellite position error correction, satellite clock error correction, ionosphere error correction are discussed very detailedly. Because the precision belows our expectation , Hatch carrier phase filter is introduced .All of them are realized in software embed in a Chinese WADGPS receiver.The fifth part of this paper analyses the doppler frequency, this part first gives the analysis of the effect of doppler frequency on gps signal . Then, gives the simulation result of second rank DPLL. the tracking performance of the second rank DPLL is very poor in a big dynamic environment., so revised assistant DPLL was introduced ..At the end of this part, the tracking performance of revised assistant second rank DPLL and second rank DPLL are compared with each other .and the result shows that the former has better dynamic tracking performance.