A Theoretical Approach to Observability Analysis of the SDINS/GPS in Maneuvering with Horizontal Constant Velocity

Abstract

A theoretical method for analyzing the observability of a strapdown inertial navigation system (SDINS) integrated with the global positioning system (GPS) is proposed. The analysis is perfomled based on two types of manellvers for a vehicle on a horizontal tr에 ectory: level flight with constant north velocity and level flight 씨th constant east velocity. The observability also is analyzed lIsing the convergence theorem, stationary state observability analysis reslllts, and Kalman filter measurement infonnation to rearrange the SDINS error model eqllation. The state variables are divided into observable and lInobservable parts, and detemline which state variables are observable and estimable with some errors from the relationship of observable and lInobservable state variables. Ollr reslllts have shown that the north and east axes accelerometer bias errors were unobservable, and that attitude errors, and east and down axes gyro bias errors 、ν;ere estimable with some unkno'vvn bias errors. It has been shøwn that horizontal manellvering improves the observability of do、vn axis gyro bias error compared 써th the stationary state, and the estimation errors of the heading error state and east axis gyro bias error are dependent on the magnitude of north velocity. The results of the theoretical observability analysis are confinned throllgh computer simulation.