基于时频边界拟合的NZ估计优化方法

NZ Estimation Optimization Method Based on Time-frequency Boundary Fitting

奈奎斯特折叠接收机(NYFR)可以用少量设备实现宽带雷达信号接收,而测量接收信号的波形参数需要正确估计信号所在的奈奎斯特区(NZ)。针对目前广泛应用的线性调频(LFM)信号,在分析LFM信号经NYFR采样后时频图的基础上,对基于时频边界拟合的NZ估计方法进行了优化;讨论了NYFR结构中本振信号的调制系数和调制频率对该方法性能的影响,给出了NYFR的参数选择策略。仿真结果表明,优化后的时频边界拟合方法在信噪比优于-9 dB时,正确检测概率可达100%。

Nyquist folding receiver(NYFR)can achieve wideband radar signal reception with a small number of devices,and measuring the waveform parameters of the received signal requires a correct estimation of the Nyquist zone(NZ)where the signal is located.Aiming at the current widely used linear frequency modulated(LFM)signal,the NZ estimation method based on time-frequency boundary fitting is optimized on the basis of analyzing the time-frequency graph of the LFM signal sampled by NYFR.The influence of the modulation coefficient and modulation frequency of the local oscillator signal in NYFR structure on the performance of the proposed method is discussed,and the NYFR parameter selection strategy is given.The simulation results show that the optimized time-frequency boundary fitting method can achieve 100%correct detection probability when the signal-to-noise ratio is better than-9 dB.