Patent ID: 8373591
Filing Date: 2013-02-12
Classification: G01S

Abstract:
1. A system for sensing aircraft and other objects comprising: (a) four or more orbiting satellites; (b) an antenna; (c) a receiver; (d) a data buffer; (e) a cross-correlator with two or more inputs and one or more outputs; (f) a system controller; (g) a list of code keys; (h) a display; wherein (a) each of said four or more orbiting satellites is configured to transmit a signal encoded by a unique code key selected from said list of code keys, (b) said antenna is connected to said receiver, (c) the output of said receiver is connected to the input of said data buffer, (d) the output of said data buffer is connected to a first of said two or more inputs of said cross-correlator, (e) said system controller is configured to provide a second of said two or more inputs of said cross-correlator, (f) said system controller is configured to receive an output of said one or more outputs of said cross-correleator, and whereby (a) said system controller is configured to use said signal transmitted by each of said four or more orbiting satellites, said list of code keys, and said cross-correlator to uniquely identify each of said four or more orbiting satellites, (b) said system controller is configured to determine a distance and a direction to each uniquely identified satellite, (c) said signal from said each uniquely identified satellite is reflected by a target producing a uniquely identifiable reflected signal, (d) each said uniquely identifiable reflected signal is received by said antenna, which is connected to said receiver, which is connected to said data buffer, which is connected to said first of said two or more inputs of said cross-correlator, (e) said system controller is configured to use said list of code keys and said cross-correlator to identify each said uniquely identifiable reflected signal, (f) said system controller is configured to use each said uniquely identifiable reflected signal and said range and said direction to said each uniquely identified satellite to determine a range and a bearing to said target, and (g) said system controller is configured to display said range and said bearing on said display, and wherein (a) the range and direction to a first of said four or more orbiting satellites and the signal from said first of said four or more orbiting satellites reflected from said target produce a first ellipsoid with said first of said four or more orbiting satellites at one focal point of said first ellipsoid, said antenna at the other focal point of said first ellipsoid, and said target on the surface of said first ellipsoid, (b) the range and direction to a second of said four or more orbiting satellites and the signal from said second of said four or more orbiting satellites reflected from said target produce a second ellipsoid with said second of said four or more orbiting satellites at one focal point of said second ellipsoid, said antenna at the other focal point of said second ellipsoid, and said target on the surface of said second ellipsoid, (c) the range and direction to a third of said four or more orbiting satellites and the signal from said third of said four or more orbiting satellites reflected from said target produce a third ellipsoid with said third of said four or more orbiting satellites at one focal point of said third ellipsoid, said antenna at the other focal point of said third ellipsoid, and said target on the surface of said third ellipsoid, (d) the range and direction to a fourth of said four or more orbiting satellites and the signal from said fourth of said four or more orbiting satellites reflected from said target produce a fourth ellipsoid with said fourth of said four or more orbiting satellites at one focal point of said fourth ellipsoid, said antenna at the other focal point of said fourth ellipsoid, and said target on the surface of said fourth ellipsoid, (e) said first ellipsoid and said second ellipsoid intersect in an ellipse with said target located on said ellipse, (f) said third ellipsoid and said ellipse intersect at two points with said target located at one of said two points, (g) said fourth ellipsoid intersects with only one of said two points with said target located at said only one of said two points.