This paper analyzes a spaceborne interferometric synthetic aperture radar (SAR) for high resolution, topographic applications. Two physical antennas are vertically spaced and are carried along parallel paths by two different platforms connected by a tether. Tethered space systems have been proposed by several authors for different applications and a joint U.S.-Italian program exists to deploy in 1992 a small satellite (Tethered Satellite System) upwards from the Shuttle. A system performance analysis is carried out, considering a theoretical study and a numerical simulation. By evaluating the Tethered Interferometric SAR impulse response, the height of various point scatterers is computed and an error budget is obtained. Results show that this system is capable of achieving a root-mean-square (rms) error in height measurement adequate for several applications. Consequently, it is a potential space system candidate for a global topographic mission, whose need has been widely recognized.
