| With the develop of Global Navigation Satellite System technology, GPS iscontinually up to date in recent years. The transition of GPS receivers are fromhardware receiver to software receiver. Base-band processing of satellite navigationsignals on software solved the problem of slowly renew and high cost on hardware. Itcan also process various satellite navigation signals. The first step of base-bandprocessing is acquisition of signals and the performance of acquisition algorithm largelydetermines the performance of the software receiver. Therefore, the study of acquisitionalgorithm has important significance in theory and practice.The acquisition of GPS signals is studied in depth in this paper. The tangible resultsand innovation are as follows:First of all, GPS basic knowledge, construction of software receiver, character ofGPS signal and generation principle are studied in depth. GPS signal acquisitionalgorithm principle, the general fast acquisition and weak signal acquisition areemphatically analyzed. The algorithms in this paper are given based on these theoreticalstudies.Secondly, this paper simulates the generation of GPS signals, fast acquisition ofGPS signals based on FFT and the improved acquisition of GPS weak signals. Thesimulate results of traditional algorithm and improved algorithm are compared andanalyzed to prove the improvements of the improved algorithm in this paper. The GPSsimulated signals can provide signal source for the study of acquisition algorithm.The innovation of thin paper is combined successive interference cancellation andingenious differentially coherent integration. The former can remove the crosscorrelated interference and the latter can capture the weak GPS signals in short time.The advantages of the two are fully used and the improved algorithm can capture thesignal with15dB/Hz C/N. It can also adjust the accumulate time automatically toshorten the acquisition time and improves the detection sensitivity at the same time. |
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