一种推广的自适应相干累积算法——基本原理与应用

Generalized Adaptive Coherent Integrator (GACI)

本文提出一种推广的自适应相干累积(GACI)算法。它是通过在自适应相干累积(ACI)算法权系数迭代公式中引入更多的动量因子,即利用权系数更多的历史信息,使被检测的单频或调频脉冲信号,在脉冲持续期间,实现自适应相干累积,从而完成弱输入信噪比(如—8dB)条件下的信号检测,而无需或很少需要知道信号的先验信息。文中叙述了算法的基本原理及部分典型的实时实验结果,指出GACI算法具有比ACI算法更好的提取弱信号的能力,预计将有广泛的实际应用前景。

Adaptive Line Enhancer (ALE) can detect and track transient signal in noise [1-5]. Adaptive Coherent Integrator (ACI) is better than ALE both in detecting and tracking the signal [6-10]. The main contribution of this paper is that a new modified LMS algorithm is proposed. The performance of the new algorithm is better than ACI algorithm. The signal detector based on the new algorithm works even when the input signal-to-noise ratio is very low. Compared with ACI, the new signal detector has the following features: 1. More coherent integrated terms are introduced into the weight updating equation. Thus it is easier to guarantee the adaptive integration action, and then very weak signals can be detected and tracked. 2. Both ACI and ALE are the special cases of the new signal detector. So we call it Generalized Adaptive Coherent Integrator (GACI). 3. The authors take full advantage of the power of TMS320C25 digital signal processor chip to handle easily the great amount of calculations required by GACI. GACI requires much more computation work than ACI or ALE. The authors perform some typical realtime experiments. The results show that GACI works very well. It is expected that GACI can find numerous applications in radar, sonar, communica- tion, seismic signal processing and other related fields.