Aerospace Robotics Laboratory, Stanford University, Stanford CA 94305 USA

Abstract

Inertial navigation reference units are often thought of as simply a navigation device which must be augmented by another device to damp the Schuler oscillation and characteristic long-term drift. Emerging applications of Am’s, however, demonstrate a need for increasingly sophisticated inertial sensors. These inertial sensors are used not only for navigation, but as importantly, they provide data for sensor stabilization. Inertial systems have also traditionally represented a significant hotel load, been heavy, bulky, and a source of acoustic and structure-borne noise. This paper presents an overview of two new inertial systems that are now in production at the Guidance and Control Systems Division of Litton Systems, Inc. These units are small, lightweight, require little power, and are silent. Data are presented that show long-term performance as well as shortterm attitude, position, and velocity reference data for the LN-100 system. Attitude, velocity, and body axis rate data are required for stabilization of such devices as laser line scanners and long baseline side-scan sonars. The relationship between the characteristics of these sensors and inertial type errors is explored. This analysis shows that it is not sufficient to specify the inertial system only in terms of its navigation CEP. The specification of the inertial unit must also be based on the needs of the sensor payload and include such considerations as short-term stability, the noise content, phase, and bandwidth of the stabilization reference.