Method for determining the orientation of a moving platform

Claim 1

A method for continuously determining the orientation of a moving user platform at a selected time fix and in relation to the earth's ellipsoid, the platform being generally comprised of a rotating antenna, a receiver and processor means; the antenna being connected to the receiver and the processor means being operatively associated with the receiver, the method comprising the steps of: continuously transmitting encoded RF signals from a plurality of Global Positioning System (GPS) earth-orbiting satellites, such that the transmitted RF signals of each GPS earth-orbiting satellite are a pair of encoded RF signals at predetermined frequencies that are directed in a radial direction towards the earth's surface, all GPS satellites of the plurality of satellites progressively and continuously advancing in their respective orbits about the earth in relation to the moving user platform; continuously processing the encoded RF signals of a series of GPS satellites of the plurality thereof wherein the series of satellites are in the field of view of the antenna and wherein the signals of the satellites of the series are received by the antenna so that the receiver and processor means select and continuously track the signals of an optimum group of four satellites of the series, selecting a series of four equidistant peripheral points about the rotating antenna and at the same time receiving signals from each optimum-tracked satellite so as to obtain a plurality of graphically-displayed biased range data points for each optimum-tracked satellite wherein a graphically displayed range data point of an optimum-tracked satellite indicates a biased range of the optimum-tracked satellite with respect to one of the equidistant peripheral points of the series thereof, forming a series of four relatively spaced lines in relation to the graphically displayed biased range data points for each optimum-tracked satellite, wherein each line of the series extends between at least two biased range data points of the graphic display of an optimum-tracked satellite where two such data points are with respect to signals received from the optimum-tracked satellite at the same point of the selected series of equidistant points, selecting a common time fix in near real time between the graphic displays of each optimum-tracked satellite and then extending a line along the common time fix between the series of spaced lines of each graphic display so as to define a common point between the common time fix line and each spaced line of a graphic display. analytically determining by interpolation the change-in-range of each optimum-tracked satellite with respect to at least one pair of diametrically opposed points of a series of four equidistant peripheral points about the antenna by selecting a pair of common points of the graphic display of an optimum-tracked satellite wherein the selected pair of common points relates to one pair of diametrically-opposed points of the series of four equidistant points about the antenna, and wherein the difference between the selected pair of common points indicates the change-in-range of the optimum-tracked satellite of a graphic display with respect to the associated pair of diametrically opposed points of the antenna, and further determining the pitch, roll, and yaw of the rotating antenna at the selected time fix in relation to a reference plane of the antenna by using predetermined arithmetic equations that are functions of the change-in-range of each optimum-tracked satellite so as to indicate the orientation of the platform at the selected time fix.

Claim 2

A method for continuously determining the orientation of a moving user platform at a selected time fix and in relation to the earth's ellipsoid, the platform being generally comprised of a rotating antenna, a receiver and processor means; the antenna being connected to the receiver and the processor means being operatively associated with the receiver, the method comprising the steps of: continuously transmitting encoded RF signals from a plurality of Global Positioning System (GPS) earth-orbiting satellites, such that the transmitted RF signals of each GPS earth-orbiting satellite are a pair of encoded RF signals at predetermined frequencies that are directed in a radial direction towards the earth's surface, all GPS satellites of the plurality of satellites progressively and continuously advancing in their respective orbits about the earth in relation to the moving user platform; continuously processing the encoded RF signals of a series of GPS satellites of the plurality thereof wherein the series of satellites are in the field of view of the antenna and wherein the signals of the satellites of the series are received by the antenna so that the receiver and processor means select and continuously track the signals of an optimum group of four satellites of the series, selecting a series of four equidistant peripheral points about the rotating antenna and at the same time receiving signals from each optimum-tracked satellite so as to obtain a plurality of graphically-displayed biased range data points for each optimum-tracked satellite wherein a graphically displayed range data point of an optimum-tracked satellite indicates a biased range of the optimum-tracked satellite with respect to one of the equidistant peripheral points of the series thereof, forming a series of four relatively spaced lines in relation to the graphically displayed biased range data points for each optimum-tracked satellite, wherein each line of the series extends between at least two biased range data points of the graphic display of an optimum-tracked satellite where two such data points are with respect to signals received from the optimum-tracked satellite at the same point of the selected series of equidistant points, selecting a common time fix in near real time between the graphic displays of each optimum-tracked satellite and then extending a line along the common time fix between the series of spaced lines of each graphic display so as to define a common point between the common time fix line and each spaced line of a graphic display. analytically determining by interpolation the change-in-range of each optimum-tracked satellite with respect to at least one pair of diametrically opposed points of a series of four equidistant peripheral points about the antenna by selecting a pair of common points of the graphic display of an optimum-tracked satellite wherein the selected pair of common points relates to one pair of diametrically-opposed points of the series of four equidistant points about the antenna, and wherein the difference between the selected pair of common points indicates the change-in-range of the optimum-tracked satellite of a graphic display with respect to the associated pair of diametrically opposed points of the antenna, and further determining the pitch, roll, and yaw of the rotating antenna at the selected time fix in relation to a reference plane of the antenna by using predetermined arithmetic equations that are functions of the change-in-range of each optimum-tracked satellite so as to indicate the orientation of the platform at the selected time fix.