Moving vehicle attitude measuring system

Claim 1

An attitude measuring system for a moving vehicle, comprising: a plurality of fixed position antennas in said moving vehicle separated from each other by a known calibrated distance, a GPS receiver coupled to each of said fixed position antennas, each said GPS receiver adapted to receive the same GPS signals from a corresponding GSP satellite and simultaneously produce an output RF carrier signal, a phase comparator coupled to the individual RF carrier signal outputs from said receivers for comparing the RF carrier phase difference, between any two of said receivers and for producing digital phase difference signals based on the comparison, processor means coupled to said phase comparator for receiving said digital phase difference signals indicative of the line of sight pointing angles to the GPS satellite having a calculable known position, memory means coupled to said processor means and containing the latest pre-calibrated reference attitude information of the moving vehicle's attitude, and means in said processor means for calculating a coordinate frame for determining the attitude of said plurality of antennas in space and for making a comparison with said pre-calibrated reference attitude information and for producing a true attitude value (θ RPY) output signal based on said comparison and said digital phase difference signals to be applied as an input to a gyro bias calibration system or employed as a stand alone attitude signal.