一种改进的两级相干累加码捕获方法

为了提高伪码捕获性能，在分析常用相干-非相干码捕获平方损耗及捕获性能的基 础上，提出了一种改进的两级相干累加伪码捕获算法。通过在第二级累加之前对多普勒频偏 进行有效补偿，实现了相干累加，提高了捕获性能；采用FFT实现，解决了工程实现的难 度。与传统的相干-非相干累加码捕获算法相比，该方法具有捕获门限低、多普勒频偏可估 计等优点。计算机仿真表明,该方法仅比理论值恶化1 dB，具有高效的捕获性能。 同时，分析表明该方法实现简单、快捷，具有很好的工程应用前景。

An improved two-stage coherent accumulation PN code acquisition method

In order to improve the performance of PN code acquisition,a high efficient PN code acquisition approach of two-level coherent accumulation is proposed based on the analysis of traditional coherent-noncoherent PN code acquisition method.Doppler-shift is compensated before the second accumulation,which realizes coherent accumulation and improves the performance of PN code acquisition.The difficulty of engineering realization is resolved by using FFT.Computer simulations show that this method has only 1 dB attenuation in comparison with the theoretical one’s.Furthermore,it is simple and fast to realize and has wide application prospect.