Parameter Estimation of Multiple Linear Frequency Modulation Signals Sensed by Nyquist Folding Receiver Using Periodic Linear Frequency Modulation Local Oscillator

The Nyquist folding receiver (NYFR) is a new ultra-wideband (UWB) sensing structure that can sense signals in an UWB space. Since linear frequency modulation (LFM) signal is widely used in sensing systems, the NYFR may receive multiple LFM signals simultaneously. Therefore, investigating the parameter estimation of multiple LFM signals sensed by the NYFR is necessary. The original NYFR using sinusoidal frequency modulation (SFM) local oscillator (LO) is difficult to estimate the NYFR output under the complete time–frequency aliasing condition. Thus, three novel parameter estimation methods are proposed in this article based on the improved LO, which is periodic linear frequency modulation (PLFM). Two of them are fast estimation methods, which are based on the LO modulation characteristic. In addition, another parameter estimation method is based on the chirp singular value rate spectrum and integral Wigner–Ville distribution with linear canonical transform (CSVR-IWVDL), which has a better estimation performance. Finally, simulation experiments verify the effectiveness and performance of the proposed three methods.