近年来，随着GPS接收机在全球范围内多用途宽领域的应用，对卫星导航定位技术也提出了更高的要求。而基于软件无线电思想的GPS软件接收机也为开发适用于特殊环境下的高复杂度算法提供了便利。作为高性能导航的关键技术之一，微弱卫星信号接收技术是目前研究的热点。在正常情况下，接收机接收到的卫星信号的信噪比大约为-20dB，但在信号微弱的环境下，信噪比可下降20dB左右，普通的接收机很难捕获跟踪到信号，难以实现定位功能。本文针对微弱GPS卫星信号的捕获、跟踪算法进行了以下研究： 1. 介绍了GPS软件接收机的结构和工作过程。对GPS卫星信号的调制方式和复用技术进行了分析，重点研究了C/A码的相关特性以及多普勒效应对载波频率和C/A码码长的影响。研究了GPS中频信号模型，并仿真产生了数字中频信号。 2. 研究了GPS卫星信号捕获的基本原理和基本方法，并对常用的微弱信号捕获算法进行介绍，分析了相干积分算法、非相干积分算法和差分相干积分算法的特点。针对相干积分时间容易受到导航数据位翻转影响的问题，提出了两种通过检测出翻转位来提高信噪比增益的算法，一种借鉴全比特算法检测数据翻转位边沿的思想，通过比较多组数据的相干积分值检测出翻转位的位置，舍弃翻转位并对其余数据进行分块相干积分；另一种将传统的差分相干积分算法推广到对数据块的处理中，并通过比较导航数据比特长度内不同数据块的积分值粗略的估计出翻砖块的位置，舍弃翻砖块后对其它数据进行数据块差分相干积分。经过仿真验证，这两种算法均具有较高的捕获灵敏度和捕获效率。 3. 对传统的锁相环跟踪算法进行了深入的研究，针对其缺陷将卡尔曼滤波算法引入GPS卫星信号的跟踪中，并建立了系统方程和量测方程，针对标准卡尔曼滤波算法对噪声统计特性的假设过于理想且对初值的依赖程度很高的问题，提出了强跟踪Suge-Husa自适应卡尔曼滤波算法，利用Suge-Husa自适应卡尔曼滤波器能够对噪声进行实时估计的特点以及强跟踪滤波器鲁棒性好且对突变情况具有很强适应能力的特点对卫星信号进行持续稳定的跟踪，经仿真验证，该算能够实现对微弱信号的跟踪且具有良好的跟踪性能。

In recent years, with the GPS receiver applied in multi-purpose and wide fields on a global scale, satellite navigation and positioning technology is also put forward higher requirements. GPS software receiver based on software radio using a relatively common hardware platform, you can achieve different functions and complex high-performance algorithms by loading a different program, it provides a convenient and possible for the development of high complexity algorithm under the special circumstances applicable. As one of the key technologies of high-performance navigation, weak satellite signal receiver technology is currently a hot research. Under normal circumstances, the SNR of satellite signal received by the receiver is about-20dB. But in weak signal environments, the SNR can be reduced about 20dB. In this case, it is difficult for the common receiver to acquisition and tracking the signal, and can not realize the positioning function. The dissertation focuses on the algorithm for weak signal acquisition and tracking, the primary work and conclusions are as follows: 1. The structure and operation of the GPS receiver is introduced. The modulation and multiplexing of GPS satellite signals are analyzed. The correlation properties of C/A code and the Doppler Effect on the carrier frequency and the C/A code length are studied. The model of GPS intermediate frequency (IF) signal is studied for simulating digital IF signal. 2. The basic principles and methods of GPS satellite signal acquisition is studied, and the usual weak signal acquisition algorithm is introduced. The characteristics of the coherent integration algorithm, non-coherent integration algorithm and differential coherent integration algorithm are analyzed. To solove the problem that the coherent integration duration is limited by the navigation data bit flipping, two algorithms that improve the SNR gain by detecting the flip-bit are proposed. The first algorithm draws on the principle of the whole-bit algorithm. Firstly, the possible position of bit-fip is detected in 1ms through the comparison of the coherent integration results of the several groups of signal blocks. Then the rest signal which is at intervals of 20ms with the flip bit is removed, and block coherent integration is applied to its subblock signal. The second algorithm extends the traditional differential coherent integration algorithm to the processing of the block data. Firstly, the 5ms signal with possible involve bit-flipping, which was detected through the comparison of the coherent integration results of the several blocks of data, was canceled. Then block differential coherent integration is applied to its sub-block signal in rest 15ms. The simulation results show that these two algorithms can improve the acquisition sensitivity and acquisition efficiency. 3. The traditional phase-locked loop tracking algorithm is studied deeply. Because of its flaws the Kalman Filter algorithm is introduced to the GPS satellite signal track, and the tracking loop models of measurement and dynamics are built. The Standard Kanlman Filter made an ideal assumption on the noise statisitical characteristics which is inconsistent with the facts, and it is highly dependent on the initial. To solove these problems, a Strong Tracking Suge-Husa Adaptive Kalman Filter algorithm is proposed. The algorithm uses Suge-Husa Adaptive Kalman Filter to estimate the noise in real time, and take the advantage of the Stong Tracking which have a good robustness and strong ability to adapt the mutation. The simulation results show that the algorithm can track the weak GPS signal continuously and stably.