The SeaWinds scatterometer was launched on the NASA QuikSCAT spacecraft in
June 1999 and is planned for the Japanese ADEOS-II mission in 2000. In addi
tion to generating a global Ku-band backscatter data set useful for a varie
ty of climate studies, these flights will provide ocean-surface wind estima
tes for use in operational weather forecasting. SeaWinds employs a compact
" pencil-beam " design rather than the "fan-beam" approach previously used
with SASS on Seasat, NSCAT on ADEOS-I, and the AMI scatterometer on ERS-1,
2, As originally envisioned and reported, the resolution of the SeaWinds ba
ckscatter measurements were to be antenna-beamwidth limited. In order to sa
tisfy an emerging demand for higher resolution backscatter data, however, t
he SeaWinds signal-processing design has been significantly modified. Here,
the various options considered for improving the resolution of the SeaWind
s measurements are discussed, and the selected:hardware modification (the a
ddition of deramp processing for range discrimination) is described. The ra
dar equation specific to a rotating pencil-beam scatterometer with digital
range filtering is developed, and the new challenges associated with calibr
ating the resulting improved resolution measurements are discussed. A formu
lation for assessing the variance of the measurements due to fading and the
rmal noise is presented. Finally, the utility of improved resolution SeaWin
ds measurements for land and ice studies is demonstrated by simulated enhan
ced-resolution imaging of a synthetic Earth backscatter scene.