United States Patent [w]
US006107959A [ii] Patent Number: 6,107,959  Date of Patent: *Aug. 22,2000
 POSITIONING DETERMINATION USING ONE LOW-EARTH ORBIT SATELLITE
 Inventor: Nadav Levanon, Ramat Gan, Israel
 Assignee: Qualcomm Incorporated, San Diego, Calif.
[ * ] Notice: This patent issued on a continued prosecution application filed under 37 CFR 1.53(d), and is subject to the twenty year patent term provisions of 35 U.S.C. 154(a)(2).
 Appl. No.: 08/723,751  Filed: Sep. 30, 1996
 Int. CI.7 G01S 5/02; H04B 7/185
 U.S. CI 342/357; 455/12.1
 Field of Search 342/357, 457;
455/12.1, 13.1; 701/213
 References Cited
U.S. PATENT DOCUMENTS
5,126,748 6/1992 Ames et al 342/353
5.412.388 5/1995 Attwood 343/357
5.412.389 5/1995 Olds 342/357
5,500,648 3/1996 Maine et al 342/357
5,548,801 8/1996 Araki et al 455/13.1
5,552,795 9/1996 Tayloe et al 342/357
5,619,525 4/1997 Wiedeman et al 375/200
FOREIGN PATENT DOCUMENTS
0582073 2/1994 European Pat. Off G01S 5/02
8801392 2/1988 WIPO G01S 13/78
Primary Examiner—Gregory C. Issing
Attorney, Agent, or Firm—Philip R. Wadsworth; Gregory D.
A system and method for determining the position of a user terminal (for example, a mobile wireless telephone) in a low-Earth orbit satellite communications system. The system includes a user terminal, at least one satellite with a known position and velocity, and a gateway (that is, a terrestrial base station) for communicating with the user terminal through the satellites. The method includes the steps of determining a range parameter and a range-rate parameter. A range parameter represents a distance between the satellite and the user terminal. A range-rate parameter represents a relative radial velocity between that satellite and the user terminal. The position of the user terminal on the Earth's surface is then determined based on the range parameter, the range-rate parameter, and the known position and velocity of the satellite.
15 Claims, 9 Drawing Sheets