Resolution of ambiguity of position location for user terminals operating in a low earth orbit satellite system

• US 20020142781A1
• Filed: 12/29/2000
• Published: 10/03/2002
• Est. Priority Date: 12/29/2000
• Status: Abandoned Application

• Current Assignee: Globalstar Incorporated
• Original Assignee: Globalstar Incorporated
• Inventors: Sites, Michael J., Wiedeman, Robert A.
• Application Number:
  US09/750,998
• Publication Number:
  US 20020142781A1
• Time in Patent Office: Days
• US Class Current: 455/456.5
• CPC Class Codes: H04B 7/18547 for geolocalisation of a station position fixing by direction or distance determination G01S5/00
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: H04W 84/06 Airborne or Satellite Networks space-based or airborne stations H04B7/185
• CPC Class Codes: H04W 88/16 Gateway arrangements

Abstract

A method for determining whether a gateway will service a user terminal in a satellite communication system comprises the steps of (1) determining whether a position of the user terminal is ambiguous, and (2) if the position is ambiguous, then (a) determining whether a previous registration of a service provider for the user terminal matches a current service provider accessible via the gateway, and (b) if the previous registration matches the current service provider, then accepting the user terminal for service by the gateway. Alternate methods involve determining that the user terminal is at either of two ambiguous positions, and (1) determining whether both of the two ambiguous positions are within a service area of the gateway, (2) determining whether at least one of the two ambiguous positions is within a restricted area for which the gateway does not provide service, or (3) determining a parameter of a beam transmitted from the user terminal to a satellite of the satellite communication system.

Claims

1. A method for determining whether a gateway will service a user terminal in a satellite communication system, comprising steps of:

determining whether a position of said user terminal is ambiguous; and

if said position is ambiguous;

determining whether a previous registration of a service provider for said user terminal matches a current service provider accessible via said gateway; and

if said previous registration matches said current service provider, then accepting said user terminal for service by said gateway.

2. A method for determining whether a gateway will service a user terminal in a satellite communication system, comprising steps of:

determining that said user terminal is at either of two ambiguous positions;

determining whether both of said two ambiguous positions are within a service area of said gateway; and

if both of said two ambiguous positions are within said service area, then accepting said user terminal for service by said gateway.

3. A method for determining whether a gateway will service a user terminal in a satellite communication system, comprising steps of:

determining that said user terminal is at either of two ambiguous positions;

determining whether at least one of said two ambiguous positions is within a restricted area for which said gateway does not provide service; and

if at least one of said two ambiguous positions is within said restricted area, then rejecting said user terminal for service by said gateway.

4. A method for resolving a position of a user terminal in a satellite communication system, comprising steps of:

determining that said user terminal is at either of two ambiguous positions;

determining a parameter of a beam transmitted from said user terminal to a satellite of said satellite communication system; and

determining that said user terminal is at a first of said two ambiguous positions based on said parameter.

5. The method of claim 4, wherein said parameter is an antenna pattern of said beam.

6. The method of claim 4, wherein said parameter is signal strength of said beam.

7. A method for determining whether a first gateway will service a user terminal in a satellite communication system, comprising steps of:

determining, based on data from a first satellite of said communication system that has a radio frequency (RF) link to said first gateway, that a position of said user terminal is ambiguous;

determining, at a second gateway, based on data from a second satellite of said satellite communication system that does not have an RF link to said first gateway, an unambiguous position of said user terminal;

obtaining said unambiguous position from said second gateway; and

if said unambiguous position indicates that said user terminal is located in a service area of said first gateway, then accepting said user terminal for service by said first gateway.

8. A method for determining whether a gateway will service a user terminal in a satellite communication system, comprising steps of:

determining, based on data from a first satellite of said communication system that has a radio frequency (RF) link to said gateway, that a position of said user terminal is ambiguous;

obtaining, from a second satellite of said communication system that does not have an RF link to said gateway, data relating to said position of said user terminal;

determining, from said data from said second satellite, an unambiguous position of said user terminal; and

if said unambiguous position indicates that said user terminal is located in a service area of said gateway, then accepting said user terminal for service by said gateway.