中文摘要：

与传统捕获方法相比，P码信号直接捕获具有很强的抗干扰能力，因此近年来国内外对P码直接捕获方法研究也很多，这些方法大多是基于均值法和XFAST方法进行计算量的缩减，但计算量缩减对于捕获效果会有一定的影响，而对于捕获影响的定量分析以及捕获方法所适用的范围很少进行讨论。通过理论分析和仿真实验得出了典型的两种P码直接捕获方法中参数设置值和信噪比损失的关系，为这两种P码直接捕获方法的适用应用范围提供了一定的理论依据，并对基于这两种的其他捕获方法的应用范围提供了参考。

英文摘要：

Compared with traditional acquisition methods, P-code direct acquisition possesses a strong anti-jamming capability. Therefore, there have been many new computation reduction methods for P-code direct acquisition which are based on the XFAST （Extended Replica Folding Acquisition Search Technique） and average method. The computation reduction has some effect on signal acquisition, but there is no quantitative analysis on the effect and the application filed of P-code direct acquisition methods. Through theoretical analysis and simu- lation, the relationship between parameters setting and the SNR（Signal- to - noise Ratio） loss of the two typical direct acquisition methods are obtained, which is useful in application field selection, and also has the reference value for other P-code direct acquisition design.