GPS node locator using an intermediate node location for determining location of a remote node

• US 7,589,671 B2
• Filed: 08/25/2006
• Issued: 09/15/2009
• Est. Priority Date: 08/25/2006
• Status: Active Grant

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Loomis, Peter Van Wyck
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): LIU, HARRY K
• Application Number:
  US11/510,224
• Publication Number:
  US 20080048912A1
• Time in Patent Office: 1,117 Days
• Field of Search: 34235701-35717, 342/386
• US Class Current: 342/386
• CPC Class Codes: G01S 19/25 involving aiding data received from a cooperating element, e.g. assisted GPS
• CPC Class Codes: G01S 19/45 by combining measurements of signals from the satellite radio beacon positioning system with a supplementary measurement
• CPC Class Codes: G01S 5/0009 Transmission of position information to remote stations involving assistance data G01S5/0236
• CPC Class Codes: G01S 5/0036 of measured values, i.e. measurement on mobile and position calculation on base station

Abstract

A network-aided GNSS node locator for receiving GNSS signal samples. A GNSS positioning system may include a GNSS remote node for sampling a GNSS signal and transmitting the GNSS signal samples through a communication network having an intermediate node. The GNSS node locator receives the GNSS signal samples through the communication network, geolocates the intermediate node from a node ID, and uses the GNSS signal samples with the intermediate node geographical location for determining the geographical location of the remote node.

Claims

1. A method for determining a global navigation satellite system (GNSS)-based location of a remote node, comprising:

receiving GNSS signal samples through a communication network from said remote node for offloading computation from said remote node to a processor location, said communication network having an intermediate node not co-located with said remote node, all said GNSS signal samples corresponding to digitized samples of a GNSS signal, said GNSS signal received by said remote node and digitized in said remote node to convert said GNSS signal to said digitized samples, wherein said GNSS signal samples are not pseudoranges;

geolocating a node ID associated with said intermediate node for determining a geographical location of said intermediate node; and

determining, at said processor location separate from said remote node and said intermediate node, a GNSS-based geographical location of said remote node based on said GNSS signal samples and said intermediate node location.

2. The method of claim 1, wherein:

determining said GNSS-based remote node location includes using said intermediate node location as an approximate geographical location of said remote node;

using said GNSS signal samples for determining code correlation time offsets; and

using said code correlation time offsets for refining said approximate location for determining said GNSS-based remote node location.

3. The method of claim 1, wherein:

geolocating said node ID includes receiving at said processor location an Internet Protocol (IP) address for an Internet Service Provider (ISP) acting as an entry point for said remote node into said communication network and determining said intermediate node location based on said IP address.

4. The method of claim 1, wherein:

geolocating said node ID includes receiving at said processor location an identifier corresponding to a cell having a transponder for receiving a wireless signal carrying said GNSS signal samples from said remote node; and

converting said identifier to a geographical location of said cell for said intermediate node location.

5. The method of claim 1, further comprising:

receiving from said remote node a time tag for a time that said GNSS signal is received at said remote node, said time tag based on a network clock time for said communication network;

determining at said processor location a location-in-space for a GNSS satellite based on said time tag; and

using said GNSS satellite location-in-space for determining said GNSS-based remote node location.

6. The method of claim 5, wherein:

determining said GNSS-based remote node location includes using said intermediate node location for determining a unit vector between said GNSS satellite location-in-space and said intermediate node location; and

using said unit vector for determining said GNSS-based remote node location.

7. The method of claim 5, wherein:

determining said GNSS-based remote node location includes using said intermediate node location for calculating a range between said GNSS satellite location-in-space and said intermediate node location; and

using said calculated range for determining said GNSS-based remote node location.

8. The method of claim 1, wherein:

receiving said GNSS signal samples through said communication network includes receiving said signal samples at a location more than one-hundred fifty kilometers from said intermediate node and said remote node.

9. The method of claim 1, wherein:

said GNSS signal samples are signal samples captured at sample times for said GNSS signal received at said remote node from a GNSS satellite and then converted to a digital format.

10. The method of claim 1, wherein:

receiving said GNSS signal samples through said communication network includes receiving said signal samples over a distance of more than one-half a code cycle time period of said GNSS signal divided by the speed of light.

11. An apparatus for determining a global navigation satellite system (GNSS)-based location of a remote node, comprising:

a geolocator for using a node ID associated with an intermediate node, not co-located with said remote node, in a communication network for determining a geographical location of said intermediate node; and

a GNSS signal sample processor at a location separate from said remote node and said intermediate node, the GNSS signal sample processor configured to offload position determination computation from said remote node by receiving GNSS signal samples through said intermediate node, all said GNSS signal samples corresponding to digitized samples of a GNSS signal received by said remote node and digitized in said remote node to convert said GNSS signal to said digitized samples, wherein said GNSS signal samples are not pseudoranges; and

using said intermediate node location with said GNSS signal samples for determining a GNSS-based geographical location of said remote node.

12. The apparatus of claim 11, wherein:

the GNSS signal sample processor includes a GNSS code correlator for using said GNSS signal samples for determining code correlation time offsets; and

a navigation processor for using said intermediate node location as an approximate geographical location of said remote node and using said code correlation time offsets for refining said approximate location for determining said GNSS-based remote node location.

13. The apparatus of claim 11, wherein:

the geolocator is constructed for determining said intermediate node location based on an Internet Protocol (IP) address as said node ID where said intermediate node acts as an Internet Service Provider (ISP) for said remote node into the Internet.

14. The apparatus of claim 11, wherein:

the geolocator is constructed for using an identifier corresponding to a cell having a transponder for receiving a wireless signal carrying said GNSS signal samples from said remote node; and

converting said identifier to a geographical location for said cell as said intermediate node location.

15. The apparatus of claim 11, further comprising:

a time tag decoder for receiving at said GNSS signal sample processor a time tag for a time that said GNSS signal is received at said remote node, said time tag based on a network clock time for said communication network; and

wherein;

the GNSS signal sample processor is constructed for determining a location-in-space for a GNSS satellite based on said time tag; and

using said GNSS satellite location-in-space for determining of said GNSS-based remote node location.

16. The apparatus of claim 15, wherein:

the GNSS signal sample processor is constructed for using said GNSS satellite location-in-space and said intermediate node location for determining a unit vector between said GNSS satellite and said intermediate node, and using said unit vector for determining said GNSS-based remote node location.

17. The apparatus of claim 15, wherein:

the GNSS signal sample processor is constructed for using said GNSS satellite location-in-space and said intermediate node location for calculating a range between said GNSS satellite and said intermediate node; and

using said calculated range for determining said GNSS-based remote node location.

18. The apparatus of claim 11, wherein:

the GNSS signal sample processor is located more than one-hundred fifty kilometers from said intermediate node and said remote node.

19. The apparatus of claim 11, wherein:

said GNSS signal samples are signal samples captured at sample times for said GNSS signal received at said remote node from a GNSS satellite and then converted to a digital format.

20. The apparatus of claim 11, wherein:

the GNSS signal sample processor is separated from said remote node by a distance of more than one-half a code cycle time period of said GNSS signal divided by the speed light.