GPS SURVEYING WITH 1 MM PRECISION USING CORRECTIONS FOR ATMOSPHERIC SLANT PATH DELAY

Multipath and atmospheric effects can limit GPS surveying precision. W e surveyed a 43 km baseline using large diameter choke ring antennas t o reduce multipath and pointed radiometer and barometric data to corre ct for atmospheric slant delay. Based on 11 daily solutions, atmospher ic slant delay corrections improved vertical precision to 1.2 mm rms a nd horizontal precision to sub-mm. Applications for high precision GPS surveying include deformation monitoring associated viiith earthquake and volcanic processes, subsidence, isostasy, and sea level measureme nts; monitoring of atmospheric water vapor for climate and global chan ge research, and to improve the resolution of synthetic aperture radar ; calibration of satellite altimeters; and precise satellite orbit det ermination.