Abstract: Inertial navigation unit (IMU) was used as the main navigation sensor in the 3rd Stage of China Lunar Exploration Program in China. A light-weight, miniaturization and fast positioning GPS receiver suitable for high speed re-entry capsule was developed. It effectively solved the poor accuracy problem of IMU long-term error accumulation, with fusion of GPS data and IMU data. Flight results indicate that navigation result was first given by GPS receiver at 4 911.3 km orbital altitude. The effective positioning time lasts 16 min. There are two times through the black barrier area in the atmosphere. Evaluated results indicate that root mean square error of position is less than 3.67 m, and root mean square error of velocity is less than 0.19 m/s. The GPS receiver meets the high-speed re-entry flight requirements. It is feasible for application of medium or low orbit micro satellites and deep space re-entry spacecraft.