| With the rapid development of Global Navigation Satellite System(GNSS), receiver, as its significant part, assumes a new trend. The receiver design based on software radio has become a hot topic in the system, as various GNSS systems improve, multi-mode receiver is the direction of technical development. Based on this background, this paper concentrates on the research of baseband signal processing of GPS/Galileo software receiver in E1. The main work and achievements are summarized as follows:Firstly, an introduction is made concerning the GPS and Galileo system, it includes the architecture of these two systems, the in-orbit satellite and the basic principles. Then from the viewpoint of signal structure, signals of the two systems are introduced. It covers a summary of spectrum distribution, signal parameters and modulation techniques, and compares the GPS C/A code and Galileo BOC signal in the aspects of autocorrelation function and power spectrum.Secondly, main part of this paper deals with acquisition and tracking of signal in detail. In the study of acquisition, the rationale of signal acquisition is analyzed; two methods, namely the serial approach and the parallel code delay approach, are discussed. A pre-doppler search before acquisition algorithm is given, which can narrow the searching area. In the study of signal tracking, this paper analyzes two different but related parts, that is, the carrier loop and the code loop. The research on different discriminators is done through the S-curve, with their performances compared. A specific strategy is proposed to solve the particular problem in the BOC code tracking caused by its modulation.Finally, the main structure of receiver is introduced, along with the distinguishing features of software receiver. The real satellite signals are collected on the experimental platform, and are processed using the above mentioned algorithm, which verifies its feasibility.
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