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遥感学报 2008
Research on Precise Geolocation Model and Method Using Satellite Remote Sensing
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Abstract:
In the program of geolocation with environmentalmeteorological satellite, the earth location softwaremakes use of earth ellipsoid and terrain surface data in conjunctionwith satellite orbitparameterand geometry attitude, and infor- mation of the sensor and satellite geometry to compute data including geodetic longitude and latitude coordinates, height, ground to satellite direction vectorand range, and solarvector. The satellite orbitpropagationmodeland themathematical procedure which intersects the sensor s line ofsightwith the terrain surface oftheEarth aremost mi portant in the program. In order tomeetthe requirementofhigh precision geolocation forenvironmentalsatellite remote sensingdata, we have developed a new generation orbitalmotion forecastand remote sensinggeolocation software system. This system isbased on the variable order, and stepsize orbitalmotion numerical integrationmodel (DE/DEABM), and is different from conven- tionalBrouwer perturbation analyticalmode.l During the research of this system, we have studied variety ofperturbations that affect orbitalmotion. These perturbations are pronounced for satellite at low altitudes. We use high order precise EGM-96 (Earth gravitymodel) data to mi prove computing precision ofperturbation for asphericity of theEarth. Whatwe put into consideration also includes the perturbation that arises from the gravitational attraction of the Sun and theMoon, solar radiation pressure and atmospheric drag in ourworks. As case studies, we developEarth location algorithms and soft- ware for two sensors, one isFY-1D VIRR launched onMay2002, and the other isFY-3AMERSIwhichwillbe launched in early 2008. In the progress, we analyse details of the optics geometry coordinates relationship ofdetector, focalplane, main optics system and scanmirror, which are key parts of sensors. As a result, the precision of coordinates transforma- tionmodelhave been developed in this software. After severaldays ofdata computing oforbitalmotion and Earth location test forFY-1D VIRR, we find that the precision of the new software system reaches the range from centmi eters tometers. It is a great mi provement comparedwith the 1km precision ofold perturbation analyticalmethod. Overal,l it is found that the software system ofFY-1D VIRR can provide navigation accuracies ofwithin 1 km atnadir.