The second-order monostatic HF radar cross section incorporating antenna barge motion

The second-order HF radar ocean cross section is derived for the case of the transmitting and receiving antenna undergoing platform (i.e. barge) motion. The derivation for electromagnetic patch scatter begins with a general expression for the bistatically received second-order electric field. Based on an assumption that the ocean surface can be described as a Fourier series with coefficients being zero-mean Gaussian random variables, the second-order monostatic radar cross section is developed. The derivation for the hydrodynamic patch scatter follows from an earlier first-order analysis. The second-order HF radar cross section is found to consist of Bessel functions, and no singularity exists in the new electromagnetic coupling coefficient. Simulation results depict the effects of barge motion under a variety of sea states. It is evident that first-order effects spread into the second-order region and thus could have detrimental effects on wave measurement schemes.