Accelerometer based line-of-sight stabilization approach for pointing and tracking systems

Equipment operating from nonstationary platforms are subjected to angular jitter resulting from vehicle linear and angular motions. The purpose of a stabilized platform is to reject the angular disturbances so that the device modulation transfer function (MTF) is preserved at the system level. This paper describes a new platform stabilization approach where miniature, low-cost, linear accelerometers are used (instead of gyroscopes) for line-of-Sight (LOS) stabilization. This is accomplished by placing the accelerometers at strategic locations, and combining their outputs so that angular motion is determined from linear acceleration measurements. The control system uses the sensed angular accelerations to generate movement commands for the gimbal servomotors in the stabilization platform. This counter-rotates the imaging device to stabilize its LOS. The use of accelerometers allows the servo system to operate in an acceleration control mode which is more desirable than position or velocity control modes, typical of gyro-based systems, since this increases stabilization bandwidth. Substituting gyros with accelerometers provides the additional benefits of lower sensor cost, weight and power consumption, better temperature characteristics, more robustness, and higher shock resistance