Showing papers on "GPS/INS published in 1971"
01 Jan 1971
TL;DR: In this paper, a method for combining the two systems using the theory of optimal linear estimation is given, with emphasis on the effects of initialization and unmodeled errors, and the results indicate that use of the combined system during landing approach would simul- taneously reduce the cross-runway position and velocity (track angle) errors.
Abstract: Error models for the Instrument Landing System (ILS) and Inertial Navigation System (INS) are discussed. A method for combining the two systems using the theory of optimal linear estimation is given. Results of tests of the combined navigation system using a ground vehicle operating on runways and instrumented with an inertial navigator, radio receivers, and a computer, are given with emphasis on the effects of initialization and unmodeled errors. The results indicate that use of the combined system during landing approach would simul- taneously reduce the cross-runway position and velocity (track angle) errors. The combined system is relatively insensitive to the choice of initial values of certain parameters. Results are still good when the initial parameter values are chosen to approximate a real-time least square fit of INS position and velocity to the ILS localizer signal. The effects of the principal unmodeled error, platform tilt, are such that the tilt would have to be precorrected or in- cluded in the error model during approach if a poorer INS were to be employed.