基于谱图的伪码调相与线性调频复合信号参数估计

研究了基于谱图的伪码调相与线性调频（pseudo random binary code and linear frequency modulation, PRBC-LFM）复合信号参数估计算法，根据PRBC-LFM信号的谱图特点给出了其伪码参数（子脉冲宽度、脉冲重复周期和伪码重复周期等）和调频参数（载频、调制斜率）的估计方法。结合瞬时频率估计误差理论，分析了谱图窗函数窗长的选择对信号参数估计精度的影响。另外，为了评价该参数估计方法的性能，推导了PRBC-LFM信号参数估计的克拉美罗界。理论分析和仿真实验表明，选择中等长度的窗函数，在信噪比为0~10 dB范围内，该估计方法比较接近克拉美罗界。

Parameter estimation for reconnaissance signals combined with pseudo-random binary phase code and LFM based on spectrogram

A spectrogram based parameter estimation for pseudo random binary code and linear frequency modulation (PRBC-LFM) reconnaissance signals is presented. According to the spectrogram characteristic of PRBC-LFM signals, the features related to pseudo code parameters such as sub pulse width, pulse cycle and pseudo code cycle, and frequency modulation parameters such as carrier frequency, modulation slope are extracted．In addition, the affection of choice for the spectrogram window length to parameter estimation precision is analyzed in terms of IF estimation error theory. Moreover, the Cramer Rao bound (CRB) of PRBC-LFM parameter estimation is derived to evaluate the performance of the proposed method. Finally, theoretical analysis and simulation results show that the proposed method is comparatively close to CRB when the signal-to-noise ratio is at 0~10 dB and the window length is medium.