Fast acquisition of L2C CL codes based on combination of hyper codes and averaging correlation

This paper provides a direct and fast acquisition algorithm of civilian long length（CL） codes in the L2 civil（L2C） signal. The proposed algorithm simultaneously reduces the number of fast Fourier transformation（FFT） correlation through hyper code technique and the amount of points in every FFT correlation by using an averaging correlation method. To validate the proposed acquisition performance, the paper applies this algorithm to the real L2C signal collected by the global positioning system（GPS） L2C intermediate frequency（IF） signal sampler—SIS100L2C. The acquisition results show that the proposed modified algorithm can acquire the code phase accurately with less calculation and its acquisition performance is better than the single hyper code method.

基于分块折叠的GPS L2C CL码直接捕获算法研究

GPS L2C信号是GPS系统在L2频段上的新型民用信号,其主要由时分复用的CM码与CL码组成。CL码上没有导航电文的调制,所以可以进行更长时间的相干积分,适合于捕获微弱信号。但CL码码长较长,运用传统的捕获方法,难以直接捕获。提出一种基于分块折叠的捕获方法,利用折叠码与分块捕获技术,快速直接捕获CL码。与传统捕获算法相比,新算法能够实现捕获速度上的提高,且可根据需要优先考虑捕获速度或灵敏度。