Abstract: The installation mode of gyro with its related algorithm is a key aspect in the design of stabilized platforms. According to the characteristics of a three-axis stabilized platform for airborne earth observation, a novel installation mode of gyro is proposed in which the azimuth gyro is mounted on the azimuth ring, while the pitch and roll gyros are mounted on the pitch ring. The relationships between gyro output angular velocities and the distribution of motor control signals are analyzed by means of the space vector decomposition theory. Based on the system model of the stabilized platform, simulation and analysis are presented under the ideal orthogonal condition as well as the condition of a gyro installation error, and the results demonstrate the feasibility and advantage of the installation mode. Under the same conditions, the installation mode diminishes mechanical dimension, reduces weight and power cost, realizes the orthogonal measurement of three-dimension angular velocities, and simplifies the three-axis decoupling control algorithm. The research conclusion can provide reference for other types of three-axis stabilized platforms in their design of structure and gyro installation mode.

Key words: earth observation, stabilized platform, gyro, installation, decoupling, vector decomposition