摘要
针对高速无人机上行链路中大多普勒条件下长伪码捕获时间较长的问题,提出了基于FFT的分段匹配滤波捕获算法,将伪码并行捕获和载波并行捕获应用在一种算法中,利用匹配滤波器的快速相关能力提高搜索效率,介绍了其捕获原理和关键参数选取依据,利用谱线比值法提升载波估计精度,有效降低FFT扇贝效应对载波估计的影响,结合工程实际分析其捕获性能和误码性能。测试结果表明,此方法能够满足无人机高速飞行时长码快捕的需求。
Aiming at the problem of large Doppler shift in high-speed flight environment,Partial Matched Filter （PMF） acquisi-tion method based on FFT is proposed firstly,in which,parallel PN code acquisition and parallel carrier acquisition are combined in one method,and matched filter is used to improve searching efficiency.Then,the theory of capture and the method of selecting parameters are discussed.What’s more,spectrum line ratio method is used to improve the carrier estimation precision and decrease the influence of scalloping in FFT.Finally,the acquisition ability and BER performance are analyzed based on engineering practice.The result shows that the method can satisfy the needs of fast and direct acquisition of long cycle code.
出处
《无线电工程》
2014年第8期85-89,共5页
Radio Engineering
