FDA最优频率增量选取必要性分析

The Necessity Analysis of Optimal Frequency Increment Selection for FDA

在干扰背景下,深入研究了频率分集阵列(FDA)雷达选取最优频率增量的必要性。在采用最优波束形成算法进行抗干扰的前提下,推导出目标与干扰的位置关系对FDA雷达输出信干噪比(SINR)的影响,进而分析输出SINR与频率增量的关系,并得出结论:在只有副瓣干扰的情况下,可不进行最优频率增量的选取,采用常规固定的频率增量也能输出高SINR;而当存在主瓣干扰时,不当的频率增量会使得输出SINR急剧下降并形成凹陷,且这种凹陷会随着频率增量的选取呈现周期性变化,极大地影响了FDA雷达的目标检测性能。计算机仿真也验证了这种周期性的凹陷变化,这表明了FDA雷达在抗主瓣干扰时必须进行最优频率增量选取。

The necessity of optimal frequency increment selection for frequency diverse array(FDA)under interference is deeply studied.Under the premise of using the optimal beamforming algorithm for anti-jamming,the influence of the position relationship between the target and the interference source on the output signal interference noise ratio(SINR)of FDA radar is firstly derived,and the mathematical relationship between the output SINR and the frequency increment is further analyzed.The conclusion can be drawn that,in the case of only sidelobe interference,the optimal frequency increment selection is unnecessary because the fixed frequency increment can also output high SINR;however,when FDA faces with mainlobe interference,an inappropriate frequency increment may make the output SINR drop sharply and form a null.Besides,the null would periodically appear with frequency increment selection,which may greatly influence the target detection performance of FDA radar.Computer simulations also verified this periodic null,which also indicates that FDA radar must select the optimal frequency increment in the presence of mainlobe interference.