Re-extraction of the Second Order Terms of High Frequency Radio Wave Backscattering in the Presence of Uniform Surface Current

HF radar systems are widely used for the measurement of ocean surface currents and wave parameters. Theoretical analysis of high frequency radio wave backscattering from the sea has been derived in the past. Also, the relationship between Bragg frequencies and surface currents is determined and has been proved by HF radars. It is known that when surface currents are present, the Bragg frequencies move to new frequencies. Their movement is proportional to the surface current in the direction toward radar. In addition, it is observed that sea surface current changes the second order part of the spectrum of radar reflection from the sea surface. In this paper, a theoretical analysis of high-frequency radio wave backscattering from the sea in the presence of constant surface current provides a formula for the second order part of the spectrum of sea echo. This resulted in similar formulas of others but the process of formula extraction is different. This method may be used for the determination of the second order spectra of radar cross section in the presence of other types of surface current.