<title>Modeling and simulation for Sea Winds-1B system design and performance evaluation</title>

Abstract

SeaWinds-1B is a spaceborne instrument, under design at the Jet Propulsion Laboratory, to accurately measure the speed and direction of ocean surface winds at high resolutions. SeaWinds-1B consists of a scatterometer and a polarimetric wind radiometer. The scatterometer employs range compression to increase the resolution of its sigma-0 measurements. The polarimetric radiometer will be used to verify new techniques of passively measuring wind vectors from space. The SeaWinds- 1B instrument will also be used to investigate the benefits of combining scatterometer and radiometer data to increase the accuracy of resulting wind products. Since SeaWinds-1B is still in the design phase, there are many system design issues which need to be studied. To aid in such studies, a simulation is being developed which will simulate the operation of the spacecraft (attitude and ephemeris), the scatterometer instrument, and the ground data processing system (sigma-0 and wind products). The simulation will provide an estimate of the wind retrieval performance and sigma-0 measurement accuracy of the SeaWinds-1B 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 SeaWinds-1B 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 scatterometer will be applied to the SeaWinds-1B simulation.