一种基于折叠技术的GPS L2C CL码直捕算法  

Direct acquisition algorithm of GPS L2C CL signal based on folding technique

作　　者：祝雪芬[1,2] 杨冬瑞[1,2] 徐斌铖 汤新华[1,2] 陈建锋[3] 杨阳[1,2] 陈熙源[1,2] ZHU Xue-fen1,2, YANG Dong-rui1,2, XU Bin-cheng1,2, TANG Xin-hua1,2, CHEN Jian-feng3, YANG Yang1,2, CHEN Xi-yuan1,2(1. School of Instrument Science and Engineering, Southeast University, Nanjing 210096, China; 2. Key Laboratory of Micro-Inertial Instrument and Advanced Navigation Technology of Ministry of Education, Southeast University, Nanjing 210096, China; 3. Automotive Engineering Research Institute, Jiangsu University, Zhenjiang 212013, Chin)

机构地区：[1]东南大学仪器科学与工程学院,南京210096 [2]东南大学微惯性仪表与先进导航技术教育部重点实验室,南京210096 [3]江苏大学汽车工程研究院,镇江212013

出　　处：《中国惯性技术学报》2017年第6期748-752,共5页Journal of Chinese Inertial Technology

基　　金：国家自然科学基金项目资助(51405203)

摘　　要：L2C是GPS现代化Block IIR-M卫星发射的一个新民用信号,其采用了特殊的民用中等长度码(CM码)和民用长码(CL码)进行时分复用。因码长较长,CL码的快速直接捕获较难实现。为提升其捕获性能,提出一种基于时频域双折叠技术的GPS L2C CL码的快速直捕算法。通过实测GPS L2C CL信号进行验证,当时域折叠K=6,同时频域折叠m=7时,捕获时间缩短为无折叠情况的1/13.7,捕获性能大大提升。该算法综合考虑了时间的减少、幅值的降低以及噪声的增大,在减少相干积分时间和削弱相干积分性能之间建立了平衡,可以实现GPS L2C CL码的快速直捕。L2C is a new civilian signal launched by the modernized GPS Block IIR-M satellites. A special civilian medium-length code（CM code） and a long code（CL code） for time division multiplexing are used in the L2C signal. Fast acquisition of CL code is difficult to implement because of longer code length. In order to improve the performance of the acquisition, a fast direct acquisition algorithm for GPS L2C CL signals based on dual-folding technique in time and frequency domain is proposed. The collected GPS L2C CL true signal verifies that, when the dual folding of time domain and frequency domain have K=6 and m=7, the acquisition time is reduced to the 1/13.7 of that without folding. The proposed algorithm takes into account the decreases of time and amplitude as well as the increase of noise, and it creates a balance between reducing the coherent integration time and weakening the coherent integration performance. The fast direct acquisition of GPS L2C CL code can be achieved by the proposed algorithm.

关 键 词：L2C 折叠技术 直捕算法 CL码 

分 类 号：U666.1[交通运输工程—船舶及航道工程]