Bistatic SAR Raw Data Simulation for Ocean
Bistatic SAR is a potential and effective tool for ocean remote sensing, and the simulation of bistatic SAR raw data from ocean surface plays a great role in the understanding of the mechanism of bistastic SAR ocean surface imaging. In this paper, a bistaitc SAR raw data simulation model for ocean surface is presented, which includes bistatic scattering simulation and ocean echo data simulation. In our research, based on IEM scattering model, a stochastic multiscale scattering model is improved by applying the second order nonlinear modulation model, and the speckle noise and coherent time character of ocean surface are simulated in the SAR raw data simulation.
A raw signal simulator for the side-looking bistatic SAR
In this paper, we propose a new method for the raw signal simulation of the side-looking bistatic SAR based on two-dimensional FFT (2DFFT). Firstly, we analyze the geometry relationship and the range history of the side-looking bistatic SAR. Then we make a detailed and mathematical study on the approximate bistatic-to-monostatic applications (BTMA). Also we present a set of formulas to describe the equivalent relationship between bistatic SAR and monostatic. Therefore, the fast raw signal simulation method based on the 2DFFT for the monostatic SAR can be extended to the bistatic case. The simulation results prove the validity of this method.
Evolution of a gravity wave spectrum through a current gradient
Transformation of a wind wave spectrum through a region of nonuniform current is investigated. It is shown how an evolution equation for the spectral action can be arrived at by the scaling arguments introduced by Phillips (1985). A numerical model based on this equation is applied to two different current systems (a head-on current and a shear current). The model also contains an indicator of excess wave breaking activity. It is pointed out that the short wave part of the spectrum (less than 10 cm, say) is not expected to be well predicted by models like the one presented here. This is probably because excess wave breaking of the longer waves is expected to generate short waves or short-scale surface roughness, an effect not accounted for in these models.