摘要
在伪码测距系统中,高信息速率的长码直扩技术可提高通信性能、改善测距精度,但与此同时弱信号的长码捕获存在巨大挑战.为此,提出一种基于FFT技术的长码直捕改进算法,主要包括非连续式码相位搜索和并行载波多普勒搜索策略、基于位同步的全比特相干积累算法和基于频率补偿的时频二维约束Tong判决算法.理论分析和仿真结果均表明,该直捕算法不仅能降低资源消耗、缩短捕获时间、大幅度降低虚警概率,还能消除能量累加时由于比特翻转所带来的影响.所提出的算法可实现虚警概率低于10-6,检测概率大于99.5%,捕获时间小于5s的盲捕性能.
In pseudo-code ranging systems, the high rate and long code direct sequence spread spectrum (DSSS) can improve not only the communication performance but also the ranging accuracy. However, long code DSSS acquisition of weak signals is still faced with lots of challenges. Hence, an improved DSSS acquisition algorithm based on FFT was proposed, including the discontinuous search of code phase and parallel search of Doppler, the whole-bit coherent accumulation based on bit synchronization and the Tong judgment based on the frequency compensation of the time-frequency two-dimensional constraint. Both theoretical analysis and simulation results show that the proposed algorithm can substantially reduce the resource consumption and the probability of false alarm, shorten the acquisition time and eliminate the effects of data modulation under conditions of long time accumulation. In this paper such performance can be realized that the false alarm probability is less than 10-6 , the detecting probability is over 99.5% and the acquisition time is less than 5 s.
作者
韩航程
刘井龙
梁丹丹
龚巧娴
HAN Hang-cheng LIU Jing-long LIANG Dan-dan GONG Qiao-qian(School of Information and Electronics, Beijing Institute of Technology, Beijing 100081, China)
出处
《北京理工大学学报》
EI
CAS
CSCD
北大核心
2016年第9期976-982,共7页
Transactions of Beijing Institute of Technology
基金
国家自然科学基金资助项目(61301089)
关键词
长码直捕
高数据率
低信噪比
搜索策略
Tong判决
direct acquisition of longcode
high datarate
low SNR
searching strategies
Tong detector