An INS/dual-antenna integrated missile positioning method is presented to overcome the problem of lacking of positioning information in SAR scene matching application.While imaging ground objects,it is capable of measuring the height of the missile via an additional antenna system with downward beam.The positioning principle is introduced firstly and then the positioning model using relative range,Doppler frequency and the missile altitude is derived.The effects of the missile altitude measurement error on the positioning error are also given.In the next part,the method for reduction of errors resulting from the terrain elevation exactly below the missile is presented based on iteration and terrain matching,respectively,for varied hypsography.The radar system requirements of dual-antenna positioning are analyzed in the end.The simulation results show that the positioning error of the above techniques is remarkably smaller than that of using INS and barometric altimeter.