基于宽带模糊函数的DS/FH信号性能分析

Performance analysis of DS/FH signals based on wideband ambiguity function

引入直扩/跳频(DS/FH)混合扩频技术可以增强航天测控系统的电子对抗能力。推导了DS/FH混合扩频信号的宽带模糊函数表达式。通过分析得知,随着载波频率的增加,信号时长的变化对模糊值的影响减弱,宽带和窄带模糊函数间的差异减小,但在接收信号的处理中仍需考虑对信号时长变化的匹配。数值仿真分析了DS/FH信号波形在不同增益分配下的分辨率、精度、旁瓣抑制及抗干扰等性能。结果表明在一定的增益分配下,该波形具有接近理想的图钉型模糊图,适当增加跳频增益可以获得更好的分辨率和抗干扰性能。

The introduction of the hybrid DS/FH spread spectrum technology could enhance TTC systems electronic countermeasure capability.The expression of the wideband ambiguity function（WAF） is derived.It is known that,with carrier frequency increase,the difference between wideband and narrowband ambiguity function decrease for weakened signal duration impact on ambiguity function.However,signal duration change should be matched in the receiving signal processing.On the basis of the WAF expression,the performance of waveforms with various spreading gain assignment such as resolution,accuracy,sidelobe suppression and anti-jamming are simulated numerically and analyzed.Simulation results show that DS/FH signals possess almost ideal thumbtack AF plot with certain spreading gain assignment,and better resolution and anti-jamming performances would be obtained with relatively large FH spreading gain.