针对循环平稳法在多分量Chirp信号相位参数估计中参数取值范围小和低信噪比下相位参数估计精度低的问题,提出一种联合循环平稳法与多普勒模糊数搜索法的多分量Chirp信号相位参数精确估计算法。该算法针对二阶相位参数的模糊性特点,采用循环平稳法完成Chirp信号的二阶相位模糊估计,然后在二阶相位模糊估计的基础上,根据多普勒模糊数导致多普勒扩散的原理,利用多普勒模糊数搜索法解决多普勒模糊问题。仿真结果证明,与已有循环平稳算法相比,该算法的相位参数取值范围不受限,低信噪比下的相位参数估计精度约提高了30dB。雷达实测数据处理结果证明了算法的工程实用性。
An accurate estimation algorithm for phase parameters of multi-chirp signals is proposed to improve the disadvantages of operation over a limited range of phase parameter values and low estimation precision in low signal-to-noise ratio using the cyclostationarity method.The method bases on the joint cyclostationarity method and Doppler ambiguity searching method.The characteristic of ambiguous second-order phase and cyclostationarity method are employed to perform the ambiguous estimation of the second-order phase for Chirp signal.Then,the Doppler ambiguity searching method is utilized to resolve the problem of Doppler ambiguity based on the ambiguous estimation and the principle of Doppler ambiguity inducing Doppler spread.Simulation results and comparisons with the existing cyclostationarity method show that the range of phase parameter values is not limited in the proposed algorithm and the estimation precision using the proposed algorithm is improved by about 30dB.Engineering practicability of the algorithm is verified by raw radar data results.