Patent ID: 6182927
Filing Date: 2001-02-06
Classification: B64G,G01S

Abstract:
A satellite navigation system for improving overall navigation accuracythe system designed for use with a global positioning system having 24 satellites in six orbital planes at 55 degrees inclination, 12 sidereal hour periods, and right ascension of the ascending nodes offset from each other by 60 degrees, the satellite navigation system comprising:at least 12 satellites residing in a plurality of medium earth orbits, each of the plurality of orbits having a period of at least 3 sidereal hours and less than one sidereal day, and an inclination angle selected from the group consisting of angles between 35 and 75 degrees and angles between 105 and 145 degrees, each of the at least 12 satellites positioned within the plurality of orbits at sufficient elevation angles to a user such that a vertical navigation accuracy provided by the system is at least approximately 7.6 meters with at least approximately 99.9% availability; andmeans for transmitting a navigation signal to the user carried by each of the at least 12 satellites.