Abstract: A technique for resolving whole-cycle ambiguity that is inherent in phase-angle measurements of signals received from multiple satellite-based transmitters in a global positioning system. The relative position of a secondary receiving antenna with respect to a reference antenna is approximately known or approximately initially determined and then measurements from a minimum number of satellites are used to determine an initial set of potential solutions to the relative position of the secondary antenna that fall within a region of uncertainty surrounding the approximate position. Redundant measurements are taken from one or more additional satellites and used to progressively reduce the number of potential solutions to close to one. Even if the number of potential solutions is not reduced to one true solution, the number can be further reduced by using additional measurements taken at different time intervals, at which different satellite geometries prevail.

Abstract: A method and apparatus for rapidly and accurately determining the position coordinates of a remote, movable receiver relative to a fixed reference receiver. The technique utilizes successive code measurements and carrier phase measurements of both the L.sub.1 and L.sub.2 carrier signals broadcast from four or more orbiting GPS satellites. Code measurements based on a weighted average of the individual L.sub.1 and L.sub.2 code measurements in each satellite/receiver link are adjusted in accordance with the corresponding carrier phase measurement for an L.sub.1 -L.sub.2 carrier difference signal and are further smoothed over time. This yields a rapid determination of the remote receiver's position coordinates, with progressively increasing accuracy. After merely about two to three minutes of processing, a wide laning carrier phase procedure can be implemented to yield a position determination that is accurate to within about one centimeter.

Abstract: A three winding induction compass mounted in a host vehicle has each winding output coupled to an analog to digital converter. Each winding output is weighted and accumulated by a push down stack circuit to obtain a time filtered output; the filtered outputs are mapped into equivalent two winding outputs as the vehicle is turned in a 360.degree. circle to form sensitivity values from the windings readings and using these values to obtain measurement parameters which are incorporated into a least squares matrix which is solved for calibration coefficients to obtain the calibration parameters representing the distortions due to the permanent and inducted magnetism of the host vehicle and due to winding imbalance between the three windings and misorientation of the three windings. The calibration parameters are applied to the outputs of the three windings to obtain an equivalent two winding output which is normalized for determining the corrected compass heading.

Abstract: A three winding induction compass mounted in a host vehicle has each winding output coupled to an analog to digital converter. Each winding output is weighted and accumulated by a push down stack circuit to obtain a time filtered output and the maximum and minimum values of each filtered output are determined and stored as the vehicle is turned in a 360.degree. circle. The distortions due to the permanent and induced magnetism of the host vehicle and due to winding imbalance between the three windings and misorientation of the three windings are obtained from the maximum and minimum values to obtain calibration parameters. The calibration parameters for the windings are applied to the outputs of the three windings to obtain an equivalent two winding output which is normalized for determining the corrected compass heading.