Abstract: Autonomous navigation does not need any information from the land station,so it can satisfy some specific requirements.In order to describe the distribution of the geomagnetic field better,the high-accuracy dynamic model of orbit and the 10×10-order model of the geomagnetic field are established.Taking the vector and the magnitude of the geomagnetic field as the observed variable respectively,the autonomous navigation is realized by the Unscented Kalman Filter.(Suppose) that the sampling period is 10s,and the measurement noise of the magnetometer is 100nT,the results of the simulation show that the satellite navigation error is 1km、0.9km、0.3km.When the observed variable is the geomagnetic vector,otherwise it is 1.6km、1.3km、0.5km.