Understanding the formation of the Arctic Basin. 100 km in width to the right of the satellite track. The 10 m long antenna, aligned parallel to the flight track, directs a narrow radar beam onto the Earth's surface over the swath. Imagery is built up from the time delay and strength of the return signals, which depend primarily on the roughness and dielectric properties of the surface and its range from the satellite. The SAR's fine resolution in the range direction is achieved by phase coding the transmit pulse with a linear chirp, and compressing the echo by matched filtering.
Range resolution is obtained from the travel time.
Azimuth resolution is achieved by recording the phase as well as the amplitude of the echoes along the flight path. This is the 'synthetic aperture' of the radar. Operation in Image Mode excludes the other AMI operating modes, and power considerations limit operating time to a maximum of 10 min per orbit. Wave-Mode operation of the SAR provides 5 km x5 km images at intervals of 200 km along track, which can then be interpreted to provide wave spectra. The relatively low data rate allows onboard data storage, and thus a global sampling of wave spectra is obtained.