Cost-Effective, High-Accuracy Inertial Navigation

Abstract

The trend in today's navigation systems is toward Global Positioning System (GPS)/Inertial Navigation System (INS) hybrids. Whether because of GPS outage, or vulnerability, or the fact that GPS does not supply real-time attitude and heading data, there is a need for a pure, self-contained INS. In addition, certain operational scenarios require high-accuracy position, velocity, attitude, and heading data from an INS. Modern INSs are dominated by ring laser gyro (RLG) technology; these systems generally lie in the 1 nmi/h class. To obtain a factor of improvement demands either development of higher-accuracy (and hence more expensive) inertial sensors, or alternative mechanization of existing inertial sensors. An alternative mechanization ideally suited to today's RLGs is the rate bias technique. This technique solves many of the problems associated with dithered gyros and also attenuates the effects of many of the inertial sensors' errors. This paper addresses the system design, the design rationale, and flight test results demonstrating that a rate bias RLG/INS provides a cost-effective solution to the pure, high-accuracy INS requirement.