基于IFM的交叠线性调频信号参数估计

摘要

线性调频信号是脉冲压缩雷达中一种重要的脉冲压缩雷达信号,但当前的瞬时测频系统无法对其检测,更无法检测交叠信号.以瞬时测频系统为基础,分析了单线性调频信号和交叠线性调频经过瞬时测频系统的理论输出,据此提出了一种改进IFM系统的思路和解算交叠线性调频信号方法.新方法用模数转换器(ADC)对前沿未交叠的I、Q输出值进行量化和连续时间采样,得到一个信号离散频率值,应用LMS算法估计出其初始频率和调频斜率.以此为基础,根据交叠部分的I、Q输出值,估计出另一个信号参数.由Matlab/Simulink仿真验证可知,新方法能够估计两交叠线性调频信号的参数.%Linear Frequency Modulation (LFM) signals is an important intra-pulse modulation signal of pulse compression radar,but current IFM system can not detect this signal,at the same time overlapping signal can not be detected in IFM system. So based on IFM system,this paper analyzes theoretical output of single and overlapping LFM signal through IFM system. On the basis of this,an improved idea and algorithm are put forward,that can estimate parameters of overlapping LFM signal. New method uses Analog To Digital Converter (ADC)parts to make quantitative and continuous time sampling to frontier un-overlapping output value of the two orthogonal channel (I/Q),and gets discrete frequency values of one signal,at last used LMS algorithm to estimate initial frequency and frequency modulation slope of this LMF single. Based on this,according to the overlapping output values of I/Q, parameters of another signal is estimated. Simulation validation of Matlab/Simulink show that this method can estimate parameters of two overlapping singles.