一种基于TDDM裂谱信号的解模糊位搜索法

时分数据调制(TDDM)裂谱信号作为一种新调制信号,具有独有的电文翻转位模糊特性,导致了采用通常的搜索方法无法正确输出电文的现象。针对TDDM裂谱信号特性以及现有搜索方法的不足,提出了一种解模糊位搜索法。该方法主要分为合路快捕及解模糊位判决两个阶段。其合路快捕阶段,不但可以快速缩小搜索范围,而且可以避免由扩频方式而引起的漏捕现象;解模糊位判决阶段,可以去除电文翻转位的模糊度,正确输出电文的翻转位置。在理论推导的基础上,从性能及信噪比容限角度进行了仿真测试,测试结果表明,解模糊位搜索法对TDDM裂谱信号的电文翻转位判决精度可以达到100%。

A Method of De-illegibility Search Based on TDDM Split Frequency Spectrum Signal

The aim of accurately outputting navigation data can not be achieved through usual search methods, because of the particular navigation data illegibility characteristic of time division data modulation (TDDM) split frequency spectrum signal as a new modulation signal. Wherefore, a de-illegibility search method is proposed, according to the TDDM split frequency spectrum signal characteristic and the deficiency of usual search methods. The unite-channels fast acquisition phase and the de-illegibility-judge phase are included in this method. The search range is reduced and the leak acquisition phenomenon is avoided through the unite-channels fast acquisition processing. The navigation data illegibility is eliminated and the navigation data is accurately output through the de-illegibility-judge processing. Furthermore, based on theoretical derivation, simulation tests are carried out from the perspectives of performance and the signal to noise ratio (SNR) limit, and the results show that the output accuracy of the navigation data reaches up to 100%.