Spaceborne GPS for POD and Earth Science

With the emergence of spaceborne geodetic receivers, GPS is rapidly invading the realm of Earth remote sensing. Among the current science applications are centimeterlevel precise orbit determination; gravity model improvement; high resolution ionospheric imaging; and atmospheric limb sounding to recover precise profiles of atmospheric density, pressure, temperature, and water vapor distribution. In the near future we may also see spaceborne GPS used for direct ocean altimetry and scatterometry. Almost uniquely among science sensors, GPS receivers lend themselves to incorporation into highly miniaturized, low cost, and fully autonomous sensorcraft.