The geolocation algorithm of Space borne Synthetic Aperture Radar(SAR) is the fundamental for developing geocoded ellipsoid correction(GEC) and geocoded terrain correction(GTC) algorithm

so it is very important to develop high accuracy geo location algorithm for the application of SAR imagery. After detailed investigation of the currently available SAR geo location algorithms

a new geo location methodology AIRGM (Analysis and Iterating Routes Based Geolocation Method) was developed. AIRGM was developed from the pure analysis geo location method (AGM) by integrating numerical iteration routes into AGM. So this new geo locationmethodology has advantages ofboth pure analysis method(efficient) and pure numericalmethod(high geolocation accuracy). Applying the three geolocation methods to one scene of ERS22 SAR SLC imagery

the geolocation accuracy of AIRGM was compared with the other two published geolocation methodologies(ASF and AGM) through two kinds of validation method. The first validation method takes the geographic coordinate of the four image corner points provided with SAR data as reference

while the second method takes 14 ground control points(GCPs) collected from 1∶50 000 geographicalmap sheets as reference. Ithas been shown that the new geo location algorithm can achieve higher geo location accuracy

and the efficiency of geo location processing ismuch higher than the pure numerical geolocation method(ASF)

which is built up on many iteration routes.