Adaptive Elimination of Ionospheric Contamination for HF Skywave Radars

In this paper, an adaptive elimination algorithm is proposed based on phase estimation to solve the problem of returns´ smearing caused by the ionospheric contamination in sky-wave over-the-horizon (OTH) radar. Three steps are included in the developed algorithm for acquiring the optimum ionospheric disturbance estimation. To get the contaminated first-order Bragg spectra suited to process, an adaptive band-pass filter is firstly introduced as a pre-process step. Then, a prior knowledge of the amplitude difference between the two first-order Bragg peaks is adopted to suppress the background noise effect on the ionospheric disturbance estimation. And finally, an iterative process is applied to optimize the results. A simulation example is given to demonstrate that the method is efficient in reconstructing Doppler spectra and increasing probability of detection in real-time.