Method and apparatus for a global positioning data service

• US 5,999,125 A
• Filed: 07/31/1996
• Issued: 12/07/1999
• Est. Priority Date: 07/31/1996
• Status: Expired due to Term

• Current Assignee: CDC Propriete Intellectuelle
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Kurby, Christopher Neil
• Primary Examiner(s): Issing, Gregory C.
• Application Number:
  US08/690,097
• Time in Patent Office: 1,224 Days
• Field of Search: 342/352, 342/357, 342/357.03, 342/357.09, 342/357.1, 342/357.16, 342/357.02, 455/12.1, 455/13.1, 455/456, 701/213
• US Class Current: 342/357.52
• CPC Class Codes: G01S 19/06 employing an initial estimate of the location of the receiver as aiding data or in generating aiding data
• CPC Class Codes: G01S 19/258 relating to the satellite constellation, e.g. almanac, ephemeris data, lists of satellites in view
• CPC Class Codes: H04B 7/18552 using a telephonic control signal and a second ranging satellite determining absolute distances from a plurality of spaced points of known location G01S5/14

Abstract

In a telecommunication system (15) with at least one gateway (1), subscriber units (2), system controller (3), at least one communication satellite (4) and global positioning satellites (5), gateway (1) provides a global positioning data service to subscriber units (2). Gateway (1) receives ephemeris and almanac data on link (7) from global positioning satellites (5). Requests for portions of the data are received via link (11) and these portions are transmitted on link (10). Subscriber unit (2) receives on link (6) positioning information which is used by subscriber unit controller (33) to self-determine accurate location data. Subscriber unit (2) transmits a global positioning data service request via link (8) and receives the requested global positioning data service data via link (9).

Claims

1. In a global telecommunication system comprising a plurality of global positioning satellites, a plurality of communication satellites interconnected through data communication links into a global communication system, a plurality of subscriber units located proximate to a surface of an earth, and at least one gateway, a method for providing a global positioning data service to said plurality of subscriber units from said at least one gateway via said plurality of communication satellites, the method comprising the steps of:

a) a gateway of said at least one gateway, said gateway being coupled to said global communication system and to said plurality of global positioning satellites, receiving location information from said plurality of global positioning satellites, computing and storing almanac and ephemeris data for said plurality of global positioning satellites;

b) a subscriber unit of said plurality of subscriber units, said subscriber unit being coupled to said plurality of communication satellites, wherein said subscriber unit obtains coarse location data from at least one of said plurality of communication satellites and to said plurality of global positioning satellites, transmitting a request for said global positioning data service to said gateway via said plurality of communication satellites, said request comprising said coarse location data of said subscriber unit;

c) said gateway determining a constellation of global positioning satellites from said plurality of global positioning satellites using said coarse location data and providing almanac and ephemeris data for said constellation to said subscriber unit as global positioning data service data if said subscriber unit is a valid requester;

d) said subscriber unit using said global positioning data service data to self-determine accurate location data for said subscriber unit using said constellation of global positioning satellites; and

e) said subscriber unit storing said global positioning data service data and said accurate location data.

2. The method, as claimed in claim 1, additionally comprising the step of:

said subscriber unit transmitting said accurate location data to said gateway using at least one communication satellite in said plurality of communication satellites.

3. In a telecommunication system comprising a plurality of global positioning satellites, a plurality of communication satellites interconnected through data communication links, at least one gateway, and a plurality of subscriber units located anywhere proximate to a surface of an earth, a method of operating a gateway which is coupled to said plurality of communication satellites and to said plurality of global positioning satellites to provide global positioning data service data to a subscriber unit which is coupled to said plurality of communication satellites and to said plurality of global positioning satellites, said method comprising the steps of:

a) receiving location information from said plurality of global positioning satellites;

b) decoding ephemeris and almanac data for said plurality of global positioning satellites from said location information;

c) storing said ephemeris and almanac data for said plurality of global positioning satellites;

d) receiving a request for said global positioning data service data from said subscriber unit, said request comprising coarse location data for said subscriber unit, wherein said subscriber unit determines said coarse location data from at least one of said plurality of communication satellites;

e) determining a constellation of global positioning satellites from said plurality of global positioning satellites using said coarse location data obtained from said request, determining almanac and ephemeris data for said constellation; and

f) transmitting via said plurality of communication satellites said almanac and ephemeris data for said constellation as said global positioning data service data to said subscriber unit.

4. The method as claimed in claim 3 additionally comprising the steps of:

g) receiving accurate location data from said subscriber unit; and

h) storing location data for said subscriber unit.

5. The method as claimed in claim 3 wherein step a) further comprises the step of:

a1) tracking a first number of satellites of said plurality of global positioning satellites as said first number of satellites are visible to said gateway.

6. The method as claimed in claim 3 wherein step b) further comprises the step of:

b1) determining current ephemeris and almanac data for all satellites of said plurality of global positioning satellites.

7. The method as claimed in claim 3 wherein step c) further comprises the step of:

c1) storing current ephemeris and almanac data for all satellites of said plurality of global positioning satellites.

8. In a telecommunication system comprising a plurality of global positioning satellites, a plurality of communication satellites interconnected through data communication links, at least one gateway coupled to said plurality of communication satellites and to said plurality of global positioning satellites, and at least one subscriber unit, coupled to said plurality of communication satellites and to said plurality of global positioning satellites, located anywhere proximate to a surface of an earth, a method of operating said at least one subscriber unit comprising the steps of:

a) determining coarse location data from at least one of said plurality of communication satellites;

b) sending to said at least one gateway via said plurality of communication satellites a request for global positioning data service data, wherein said request comprises said coarse location data;

c) receiving said global positioning data service data from one of said at least one gateway via said plurality of communication satellites, wherein said global positioning data service data comprises ephemeris and almanac data for a constellation of global positioning satellites which said at least one gateway has determined using said coarse location data;

d) processing said global positioning data service data;

e) using said ephemeris and almanac data for said constellation of global positioning satellites to self-determine accurate location data for said at least one subscriber unit; and

f) sending said accurate location data to said at least one gateway.

9. The method as claimed in claim 8 wherein step a further comprises the steps of:

a1) determining when accurate location data is not valid;

a2) determining when stored global positioning satellite almanac data is not valid; and

a3) determining when stored global positioning satellite ephemeris data is not valid.

10. A telecommunication system comprising:

a plurality of global positioning satellites;

a plurality of communication satellites interconnected through data communication links;

at least one gateway comprising means for establishing communication links with at least one of said plurality of global positioning satellites, means for establishing communication links with at least one of said plurality of communication satellites, means for receiving a request for global positioning data service data from a subscriber unit, means for receiving coarse location data for said subscriber unit from said request, means for determining a constellation of global positioning satellites from said plurality of global positioning satellites using said coarse location data;

means for determining almanac and ephemeris data for said constellation, and means for transmitting via said plurality of communication satellites said almanac and ephemeris data for said constellation as said global positioning data service data to said subscriber unit; and

at least one subscriber unit comprising means for establishing communication links with at least one of said plurality of global positioning satellites, means for establishing communication links with at least one of said plurality of communication satellites, means for determining coarse location data for said at least one subscriber unit from at least one of said plurality of communication satellites, means for sending a request for global positioning data service data to a gateway, said request comprising said coarse location data, means for receiving via said plurality of communication satellites said almanac and ephemeris data for said constellation as said global positioning data and means for using said almanac and ephemeris data for said constellation to determine accurate location information to decrease battery drain in said at least one subscriber unit.

11. The telecommunication system as claimed in claim 10, wherein each of said at least one gateway comprises:

means for storing said global positioning data service data.

12. A telecommunication system as claimed in claim 10 wherein said at least one subscriber unit comprises:

means for storing said global positioning data service data.

13. In a telecommunication system comprising a plurality of global positioning satellites, a plurality of communication satellites interconnected through data communication links, a plurality of subscriber units coupled to said plurality of communication satellites and to said plurality of global positioning satellites, wherein said plurality of subscriber units can be located anywhere proximate to a surface of an earth, and at least one gateway coupled to said plurality of communication satellites and to said plurality of global positioning satellites, a method for providing a global positioning data service to said plurality of subscriber units from said at least one gateway, said method comprising the steps of:

a) a gateway of said at least one gateway processing location information received from said plurality of global positioning satellites to determine ephemeris and almanac data for said plurality of global positioning satellites;

b) a subscriber unit of said plurality of subscriber units self-determining coarse location data for said subscriber unit using information received from at least one of said plurality of communication satellites;

c) said subscriber unit transmitting a request for said global positioning data service to said gateway via said plurality of communication satellites, wherein said request includes said coarse location data and a request for certain portions of said ephemeris and almanac data for said plurality of global positioning satellites;

d) said gateway using said coarse location data and said request for certain portions of said ephemeris and almanac data to determine which portions of said ephemeris and almanac data to send as global positioning data service data to said subscriber unit;

e) said gateway providing said global positioning data service data to said subscriber unit if said subscriber unit is a valid requester;

f) said subscriber unit using said global positioning data service data to self-determine accurate location data for said subscriber unit using said plurality of global positioning satellites; and

g) said subscriber unit storing said global positioning data service data and said accurate location data.

14. The method, as claimed in claim 13, additionally comprising the step of:

said subscriber unit transmitting said accurate location data to said gateway using said plurality of communication satellites.