混沌扩频测控系统码跟踪性能分析

Analysis of DLL Tracking Performance in Chaotic Spread Spectrum TT&C System

混沌信号的非周期性有助于解决距离测量中的模糊问题,使得它在测控系统中具有巨大应用吸引力。混沌扩频测控系统的码跟踪抖动,除了来源于加性噪声影响之外,还受到数字化混沌序列相关函数旁瓣随机性的影响。根据码跟踪原理与混沌码特性,给出了混沌码相关函数旁瓣随机性影响下码跟踪环路鉴相增益随机性的计算方法,分析了混沌扩频测控系统的码跟踪性能。结果表明,混沌码相关函数随机性的存在,使码鉴相增益产生随机性,它与环路稳态误差的相互作用对跟踪精度产生有限影响。分析结果可以为混沌序列在扩频测控系统中的应用提供支持与参考。

The aperiodicity of chaotic signal is useful to remove the range ambiguity in Tracking, Teleme-try, and Control（TT＆C）system. Besides the additive white Gaussian noise（AWGN）, the delay locked loop（ DLL） in chaotic spread spectrum TT＆C system is also disturbed by the randomicity of digital chaotic signal autocorrelation function sidelobe. Based on the priciple of DLL and the character of chaotic code, a method to calculate the gain of code delay discriminator is presented, and the tracking performance of cha-otic spread spectrum TT＆C system is discussed. It is concluded that the randomicity of chaotic code core-lation function gives arise to the randomicity of discriminator gain, which degrades the tracking accuracy slightly. The results in this paper are useful for understanding the application of chaotic spread spectrum code in TT＆C system.