Modeling and simulation for SeaWinds-lB system design and performance evaluation

SeaWinds1 B is an spaceborne instrument, under design at the Jet Propulsion J.-aboriitory, to accurately measure the speed and direction of ocean surface winds at high resolutions. SeaWinds-l B consists of a scatterometer and a polarimetric wind radiometer. The scatterometer employs range compression to increase the resolution of its sigma-O measurements. The polanmetric radiometer will be used to verify new techniques of passively measuring wind vectors from space. The SeaWinds-l B instrument will also be used to investigate the benefits of combining scatterometer and radiometer data to increase the accuracy of resulting wind products. Since SeaWinds1 B is still in the design phase, there arc many system design issues which need to be studied. To aid in such studies, a simulation is being develo~ which will simulate the operation of the spacecraft (attitude and ephemeris), the scatteromcter instrument, and the ground data processing system (sigma-O and wind products). The simulation will provide an estimate of the wind retrieval performance ad sigma-O measurement accuracy of the SeaWindsIB scatterometer over realistic wind fields and land targets. Perhaps the most important features of any simulation are the considerations that are used to guide its construction. The SeaWindsI B simulation will incorporate many factors including instrument RF stability, measurement,error correlation, geophysical model function errors, and spacecraft attitude stability. Experience from simulations devised for the NASA Scatterometer (NSCAT) and SeaWinds scattemmeter wil I he applied to the SeaWindslB simulation.