无线电工程
無線電工程
무선전공정
RADIO ENGINEERING OF CHINA
2014年
8期
85-89
,共5页
直扩%FFT%多普勒%伪码捕获
直擴%FFT%多普勒%偽碼捕穫
직확%FFT%다보륵%위마포획
DSSS%FFT%Doppler%PN code acquisition
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。
針對高速無人機上行鏈路中大多普勒條件下長偽碼捕穫時間較長的問題，提齣瞭基于 FFT 的分段匹配濾波捕穫算法，將偽碼併行捕穫和載波併行捕穫應用在一種算法中，利用匹配濾波器的快速相關能力提高搜索效率，介紹瞭其捕穫原理和關鍵參數選取依據，利用譜線比值法提升載波估計精度，有效降低 FFT 扇貝效應對載波估計的影響，結閤工程實際分析其捕穫性能和誤碼性能。測試結果錶明，此方法能夠滿足無人機高速飛行時長碼快捕的需求。
침대고속무인궤상행련로중대다보륵조건하장위마포획시간교장적문제，제출료기우 FFT 적분단필배려파포획산법，장위마병행포획화재파병행포획응용재일충산법중，이용필배려파기적쾌속상관능력제고수색효솔，개소료기포획원리화관건삼수선취의거，이용보선비치법제승재파고계정도，유효강저 FFT 선패효응대재파고계적영향，결합공정실제분석기포획성능화오마성능。측시결과표명，차방법능구만족무인궤고속비행시장마쾌포적수구。
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.
