一种基于高效FrFT的LFM信号检测与参数估计快速算法

摘要

A fast algorithm based on the effective FrFT is proposed to realize the detection and parameter estimation of Linear Frequency Modulation (LFM) signal, since the traditional algorithms have a great computational burden. The effective FrFT is first analyzed, and pointed out to have problems in choosing the rotation angles, being easily affected by initial frequency, and poor anti-noise performance.Faced with the above problems, a modified power spectrum smooth filtering method is used to improve the effective FrFT algorithm. The theoretical analysis indicates that the proposed method based on effective FrFT can realize the detection and parameter estimation of LFM signal in low SNR condition with only three rotation angles. Furthermore, the computational cost is greatly reduced under the guarantee of the same parameter estimation accuracy compared to traditional FrFT. The simulation results verify the effectiveness of the proposed algorithm.%针对传统方法对线性调频(LFM)信号检测与参数估计运算量大的问题,该文提出一种基于高效FrFT的快速算法.首先,分析了高效FrFT原理,指出高效FrFT存在旋转角度的选取、易受初始频率影响以及抗噪性能差等问题.针对以上问题,该文利用修正的功率谱平滑滤波方法对高效FrFT进行改进.理论分析表明,该文提出的改进算法仅用3次旋转角度即可实现较低信噪比下LFM信号的检测和参数估计.与传统的FrFT相比,在保证参数估计精度不变的情况下,运算复杂度大大降低,更符合工程上实时处理的要求.仿真结果验证了该算法的有效性.