Suboptimal Estimation of Inertial System Error States using Radar Area Correlation and Altimeter Position Measurements

摘要

The report describes one of several alternatives being explored to establish advanced guidance techniques for the Army's long range tactical missile, the PERSHING. The analysis is given for estimating the inertial measurement unit's error states in an aided terminal guidance mode. Position observations measured by a radar area correlation system and a radar altimeter are processed in an extended Kalman filter to yield the suboptimal estimates of the inertial measurement unit's errors. The dynamics of the inertial system are modeled in four coordinate systems to allow the choice of the least complex mechanization. To minimize on-board computer requirements, an analysis of the filter's performance is made by comparing the optimal filter gains with a filter formulated with fixed gains chosen a posteriori from those computed optimally.