Aspects of the determination of ocean wave parameters by means of an optoelectronic satellite sensor

Abstract

In this paper, the task and mode of operation of an optoelectronic spaceborne sensor system with CCD lines and a digital 2-D Fourier transform device for the determination of such parameters of ocean waves, like wavelength and propagation direction, are outlined. Starting from both required and estimated parameters of the sensor system, the signal-to-noise ratio of spatial frequencies of wave representation is calculated outside the glitter range. Presupposed for the simulation was a sinusoidal wave pattern with different propagation directions in relation to the sensor viewing angle and the sun elevation angle. It turns out that the optimization of the sounding direction plays an important role for the determination of wave parameters at given sun angles. Furthermore, for the interesting range of wave parameters it is sufficient to analyse an area of about 5 × 5 km. Therefore it is possible to work under partial cloudy conditions too. Obtaining good estimates for the height of ocean waves seems to be difficult with that type of sensor. As a result from comparing some types of transforms, their implementation requirements into a real-time on-board processor, and their data compression estimates, the “bottlenecks” of a very sophisticated optoelectronic sensor system are characterized.