Research On The Implementation Technology For High Sensitivity Signal Acquisition And Tracking

The application of Global Navigation Satellite System is used more and more widely,it can provide high precision, high reliable positioning, navigation and timing services forall kinds of different users on an all-weather global scale. Its position is getting more andmore important in people’s life. The navigation is based on positioning and the GNSSreceiver needs at least four star visible satellite to accomplish positioning the objective. Atpresent, the receiver is generally completed in the open sky. However, under specialcircumstances, such as in the case of tunnels and indoor environment, traditional receivercan only receive no more than three satellite signals. Therefore improving the receiversensitivity is one of the top problems in the present study and its most critical problem isthe baseband processing of weak signal. The acquisition and tracking of weak signals isthe most important of baseband processing of weak signal.This paper mainly studies the algorithm and realization technology of high sensitivityGNSS signal acquisition and tracking. First, it analyses the principle of navigation and theconstitute of signal, which is the basis of the GNSS signal acquisition and trackprocessing.And then, the paper studies acquisition algorithms of GNSS signals, including sometraditional acquisition algorithms such as serial acquisition and parallel code phaseacquisition. On this basis, it studies acquisition algorithm of weak signal. The algorithm ofModify Double Block Zero Padding is an effective algorithm, and it takes variousmeasures for coherent and incoherent of a long time to capture of15dB-Hz C/A codeweak signals validly. This paper makes a MATLAB simulation of high sensitive signalacquisition algorithm, and it designs FPGA implementation blocks of partition module.At last, the paper studies tracking algorithms of GNSS signals, which includes therealization of the carrier loop and code loop. And in the case of weak signals, thetraditional tracing method cannot track signal, so the kalman filter algorithm is used torealize the weak signals tracking. The paper makes a MATLAB simulation for trackingalgorithm, the results show that the tracking algorithm has a better tracking ability for27dB-Hz weak signal.