Simulation Of Bistatic HF Radar Sea Clutter And Its Suppression Based On SVD

Making use of the diffraction of radar beam around the earth's surface,the high frequency ground wave over the horizon radar(HF-GWR) can detect targets such as vessels,low flying altitude and cruise missiles at an over the horizon distance.It not only has a large remote sensing area and low cost,but also can be used to compensate for the low altitude blind zone of the conventional microwave radar and the short range blind zone of the sky wave OTH radar, Nor do they need to pay attention to changes in the ionosphere. In addition it has an ability of anti-stealth and antagonizing anti-radiation missiles, So it is widely used in the national economy and national defense field in many countries. The main mechanism between HF radar incident electromagnetic waves and the sea is the Bragg scattering, e.g for the low-angle, the first order scattering only happens between the incident electromagnetic waves and the ocean waves whose wavelengths are equel to half of the radar wavelength.There are also second-order or higher-order scattering, the characteristics of scattering signal depend on the radar operating frequency, beam width, polarization mode and structures (monostatic or bistatic). In order to study the electromagnetic wave scattering of ocean surface , it is necessary to study its scattering mechanisms and establish a high-frequency radar scattering cross-section model of the ocean surface.This paper introduces the concept of ocean wave energy spectrum,describes several semi-empirical models, including Neumann spectrum, Pierson - Moscowitz (P-M) spectrum, JONSWAP spectrum etc. and compares them, Pierson - Moscowitz (P-M) spectrum is adopted in the simulation of this paper.Then, the high-frequency radar sea surface Bragg scattering mechanism is introduced, the first and second-order sea clutter scattering cross section equations of bistatic high-frequency radar are intuoduced too.A detailed analysis of an algorithm to solve second scattering cross section equation is given, numerical simulation is carride out according to the analysis algorithm, the results were analyzed and we can know the impact on the sea clutter spectrum of the bistatic radar parameters (operating frequency, double-base angle) and the sea state (wind direction, wind speed).Consider that the bistatic sea clutter spectrum may be wider compared to monostatic spectrum,this paper make a primary discuss and analysis of its principle and extent. Finally the supression method of sea clutter based on the singular value decomposition (SVD) is studied and simulated.