Novel order-select method of polynomial modeling for ionosphere phase perturbation correction

Ionosphere phase perturbation made the clutter spectrum of sky-wave over-the-horizon radar (OTHR) spread and influenced low-speed object detection such as ship. Recently, an algorithm based on piecewise polynomial phase modeling and high-order ambiguity function(HAF) is developed aiming at this problem. How to select the model order rationally is critical in the algorithm application. Two improved order-selecting methods of self-adaptive polynomial modeling are proposed and verified by simulation. The results indicate that the new method (frequency-domain and time-domain) based on the transform characteristic of high-order ambiguity function is improved greatly in accuracy and the amount of calculation is reduced. And the polynomial order can be judged exactly with low signal-to-noise ratio (SNR) when employing the frequency-domain method.