satellite methods  search
UFsatellite measurements
RTgeophysical methods
 Doppler effect
 geophysical surveys
 geodesy
 Geosat
 AVHRR
 broad-band spectra
 geodetic coordinates
 Earth Observing System
 ERS-1
 Global Positioning System
 Gravsat
 ground truth
 image enhancement
 Landsat
 Lageos
 laser ranging
 Long Duration Ex
SNUsed for artificial satellites. For natural satellites, see satellites. Before 1978, search satellite AND methods. For surveys, also index the area.