Method and apparatus for enhancing a global positioning system with a terrain model

• US 6,590,530 B2
• Filed: 03/07/2002
• Issued: 07/08/2003
• Est. Priority Date: 11/17/2000
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Global Locate Incorporated (Broadcom, Inc.)
• Inventors: Abraham, Charles, van Diggelen, Frank
• Primary Examiner(s): Phan, Dao
• Application Number:
  US10/093,215
• Publication Number:
  US 20020089446A1
• Time in Patent Office: 488 Days
• Field of Search: 342/357.13, 342/357.06, 342/357.01, 342/462
• US Class Current: 342/357.33
• CPC Class Codes: G01S 19/50 whereby the position solution is constrained to lie upon a particular curve or surface, e.g. for locomotives on railway tracks

Abstract

A method and apparatus that computes three-dimensional position using a terrain model and pseudorange measurements that are computed satellite signals. The pseudorange measurements provide a set of possible positions and the terrain model is used to identify the correct position amongst the possible positions.

Claims

1. A method for computing position comprising:

supplying pseudorange measurements that approximate the distance from a location to a plurality of global positioning system (GPS) satellites;

determining a set of possible positions using said pseudorange measurements;

supplying a terrain model; and

computing a three-dimensional position by identifying an intersection of said set of possible positions and a surface defined by said terrain model.

2. The method of claim 1, wherein said pseudorange measurements are computed within a GPS receiver.

3. The method of claim 1, wherein said computing includes using said terrain model to estimate altitudes at latitude and longitude values derived from said pseudorange measurements.

4. The method of claim 1, wherein said identifying step further comprises:

executing a bisection process for identifying said intersection.

5. The method of claim 1, wherein said pseudorange measurements are derived utilizing signals from three satellites.

6. An apparatus for computing position information of a receiver, the apparatus comprises:

a positioning module that derives a plurality of pseudorange measurements to produce a set of possible positions;

a database containing a terrain model; and

a position processor that derives three-dimensional position by identifying an intersection of said set of possible positions and a surface defined by said terrain model.

7. The apparatus of claim 6, wherein said position processor uses said terrain model to estimate altitudes at latitude and longitude values derived from said pseudorange measurements.

8. The apparatus of claim 6, wherein the positioning module, database and position processor are located in a mobile receiver.

9. The apparatus of claim 6, wherein said positioning module is located in a mobile receiver and said position processor and database are located in a remote processing station, and a wireless communications link couples the mobile receiver to the remote processing station.

10. The apparatus of claim 6 wherein the positioning module computes pseudoranges for at least three global positioning system satellites.

11. Apparatus for computing position comprising:

means for supplying pseudorange measurements that approximate the distance from a location to a plurality of global positioning system (GPS) satellites;

means for determining a set of possible positions using said pseudorange measurements;

means for supplying a terrain model; and

means for computing a three-dimensional position by employing a means for identifying an intersection of said set of possible positions and a surface defined by said terrain model.

12. The apparatus of claim 11, wherein said pseudorange measurements are computed within a GPS receiver.

13. The apparatus of claim 11, wherein said computing means operates without an assumed altitude.

14. The apparatus of claim 11, wherein said identifying means further comprises:

means for executing a bisection process for identifying said intersection.

15. The apparatus of claim 11, wherein said pseudorange measurements are derived utilizing signals from three satellites.