Ionosphere Phase Decontamination for OTHR Based on Fourier Synchrosqueezed Transform

The ionosphere phase contamination of over-the- horizon radar (OTHR) leads to sea clutter and target Doppler broadening, which in turn degrades the target detection performance. To solve this problem, a method based on Fourier synchrosqueezed transform (FSST) is proposed. First, FSST is performed on the ionosphere contaminated data. Second, the time-frequency ridges are extracted and used to estimate the instantaneous frequency. Finally, the ionosphere phase disturbance error is estimated based on the instantaneous frequency, and the decontamination is realized through the phase compensation. The FSST has a higher frequency and time resolution than the other time-frequency (TF) analysis methods, and thus has a higher accuracy of the instantaneous frequency estimation. Simulation analysis shows that the FSST method has better ionosphere decontamination performance compared with existing methods.