International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada / With the development of microcomputer technology, the application of strap-down inertial navigation on aircraft is used more frequently. The attitude measurement for miniature spacecraft is most important. Installing three-axis acceleration sensors and three-axis rate gyros on the spacecraft, the accelerations and attitudes can be obtained through the PCM/FM telemetry system. Then, the initial attitude of spacecraft is given through outside measurement and telemetry. Finally, in the ground station, the parameters of spacecraft attitude are given by using strapdown inertial navigation theory and quanternion differential equation for solving the attitude.