Bistatic model of ocean scattering

An analytical closed-form model is derived for the average power echo received by a bistatic altimeter from an oceanic surface at a frequency high enough for the Kirchhoff scattering mechanism to be dominant over the Bragg resonance one. The asymmetric behavior of the sea waves is taken into account, modeling the surface height as a non-Gaussian distributed random process and an explicit expression of the so-called "electromagnetic bias" is obtained as a function of the skewness coefficient of the distribution, Results obtained applying such model to a monostatic geometry are shown to be in good agreement with those reported in literature as well as with those obtained by numerical simulations. It is also shown that, letting the "non-Gaussianity" term tend to zero, our model correctly reduces to the well-known Brown model for Gaussian surfaces. This work has been conceived in the frame of the feasibility study of a bistatic remote sensing system, consisting of a constellation of satellites flying at the same altitude with an operating geometry such that the incidence and scattering angles are equal.