研究了GPS软件接收机捕获算法;针对常规时域串行搜索算法速度慢和并行码相位频域搜索算法FFT计算量大等缺点,采用常规串行捕获算法牙口频域并行码空间捕获算法相结合的混合搜捕算法来实现对空中可见卫星的捕获;针对信号较弱情况下的卫星捕获,采用了非相关积分捕获算法;设计了中频信号仿真器,并使用其产生的仿真信号对捕获算法进行了验证。测试结果表明,混合搜捕算法能够为软件接收机提供较快的捕获能力,非相关积分捕获算法能够有效地实现微弱信号的捕获。
An acquisition algorithm based on GPS software receiver was studied. Since the conventional serial search algorithm in time domain was slow and the parallel search algorithm in frequency domain needed heavy computation, a mixed acquisition algorithm, utilizing conventional serial acquisition algorithm in time domain and parallel search algorithm of code in frequency domain was presented. To solve the acquisition of weak signal, a non-correlation acquisition algorithm was introduced. To validate the acquisition algorithm, an IF signal simulator was designed. The test results show that the mixed acquisition algorithm can provide the software GPS receiver with fast signal acquisition, and the non-correlation acquisition algorithm can effectively acquire the weak signal.