Research And Implementation Of Acquisition And Tracking Algorithm Of GPS Software Receiver

Acquisition and tracking technology, the key technology for implementation of the global positioning system (GPS) Software receiver, aims at keeping local carrier frequency and phase of spread spectrum code generated at the receiver identical with satellite signal. Furthermore, navigation data can be demodulated, with which important parameters can be obtained for computing the pseudo range and position of the receiver.The process of GPS PN code acquisition is a two-dimension lengthy searching process in time and frequency dimension.In GPS,P code has high code speed and long sequence period,so P code is very hard to be acquised.Restriction as a result of conditions this paper only research the C/A code acquisition and tracking After the process of acquisition the system must transfer to track process The function of track is achieved by code track loop and cost as loop In this paper, based on the research about the two processes of GPS synchronization work is done as follow:Analyses the characteristics of GPS signals are given, and the structure of software receiver, and analyzed the principle of acquisition and tracking technology; On the analysis of time domain method, based on relevant acquisition the signal acquisition e method algorithm of FFT, on the basis of the spectrum of GPS signal according to observation, proposed the improvement based on FFT algorithm of actual signal acquisition algorithm, acquisition eight GPS signal, the results showed that the simulated acquisition shortened the time of the acquisition; Analysis code and carrier tracking method, design on the basis of GPS receiver, and the complete tracking channels of Matlab actual GPS signal tracking performance simulation result shows that the tracking channel design to meet the design requirements; Finally, the full text summarized, and looks forward to the next step may work.