Method and apparatus for generating and using a regional-terrain model

• US 8,301,370 B2
• Filed: 05/28/2010
• Issued: 10/30/2012
• Est. Priority Date: 03/21/2006
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Global Locate Incorporated (Broadcom, Inc.)
• Inventors: Van Diggelen, Frank
• Primary Examiner(s): To, Tuan C.
• Application Number:
  US12/790,620
• Publication Number:
  US 20100235094A1
• Time in Patent Office: 886 Days
• Field of Search: 701/208, 701/409, 707/675, 348/14.1, 345/419, 345/427, 342/357.25, 342/357.34
• US Class Current: 701/409
• 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 for computing position using a regional-terrain model is provided. The method includes obtaining from at least three satellites pseudorange measurements, computing a transitional position by using a default altitude with a large uncertainty, using this transitional position to obtain from a terrain model altitude information associated with a region, and computing an accurate three-dimensional position as a function of the pseudorange measurements and the altitude information. The region defines a boundary, and the boundary includes the transitional position.

Claims

1. A method for computing position in a receiver, comprising:

obtaining pseudorange measurements at a location, with a circuit of the receiver;

determining a speed of the receiver;

comparing the speed of the receiver to a threshold value; and

if the speed of the receiver is below the threshold value,

obtaining from a regional-terrain model altitude information associated with a modeled region, wherein the location is in a vicinity of the modeled region; and

computing a position as a function of the pseudorange measurements and the altitude information,

wherein obtaining from a regional-terrain model altitude information comprises obtaining from the regional-terrain model an altitude and an altitude uncertainty.

2. The method of claim 1, wherein the altitude comprises a first altitude from a given reference point associated with the earth, and the altitude uncertainty comprises a given deviation from the first altitude.

3. The method of claim 1, wherein a boundary of the modeled region is defined by an interconnection of a number of coordinate-system points that together delineate the modeled region.

4. The method of claim 3, wherein the boundary comprises a shape selected from a group of shapes consisting of a circle, ellipse and polygon.

5. The method of claim 3, wherein the boundary is defined by a coordinate-system point and a line segment.

6. The method of claim 1, further comprising:

determining a transitional position of the location as a function of fixed altitude information and the pseudorange measurements.

7. A method for forming a regional terrain model, the method comprising:

defining at least one modeled region of the regional terrain model as a function of a boundary formed using a first altitude at a first location and at least a second altitude at a second location, wherein the first altitude and the second altitude are within a range of altitudes, including;

obtaining from a point-based terrain model the first altitude at the first location;

locating in the point-based terrain model an additional location, wherein the additional location is spaced apart from the first location;

obtaining from the point-based terrain model an additional altitude associated with the additional location;

excluding from the boundary the additional location when the additional altitude is not within the range of altitudes; and

including in the boundary the additional location as the second location when the additional altitude is within the range of altitudes; and

storing the modeled region in the regional terrain model in a memory.

8. The method of claim 7, wherein the range of altitudes are defined by an altitude and an altitude uncertainty associated with the modeled region.

9. The apparatus method of claim 7 wherein the boundary comprises a shape selected from a group of shapes consisting of a circle, ellipse and polygon.

10. A method for computing a position of a receiver, comprising:

computing a transitional position of the receiver with a circuit;

determining a speed of the receiver;

comparing the speed of the receiver to a threshold value; and

if the speed of the receiver is below the threshold value,

obtaining from a regional-terrain model altitude information associated with a modeled region, wherein the transitional position is in a vicinity of the modeled region; and

computing the position of the receiver as a function of the altitude information.

11. The method of claim 10, wherein obtaining the altitude information includes obtaining an altitude and an altitude uncertainty associated with the modeled region.

12. A method for forming a regional-terrain model, the method comprising:

collecting, at a mobile receiver, a plurality of altitudes associated with a respective plurality of positions of the mobile receiver;

defining, by the mobile receiver, at least one modeled region using the plurality of altitudes, wherein the modeled region is associated with an altitude and altitude uncertainty; and

storing the modeled region in the regional-terrain model at the mobile receiver.

13. The method of claim 12, wherein the altitude comprises a mean altitude of the plurality of altitudes, and the altitude uncertainty comprises a given deviation from the mean altitude.

14. A receiver, comprising:

a memory configured to store a regional-terrain model;

a module configured to determine a speed of the receiver and to compare the speed of the receiver to a threshold value; and

a positioning module configured to obtain pseudorange measurements associated with a location of the receiver, the positioning module further configured, if the speed of the receiver is below the threshold value, to obtain from the regional-terrain model altitude information associated with a modeled region, wherein the location of the receiver is in a vicinity of the modeled region, and to compute a position of the receiver as a function of the pseudorange measurements and the altitude information.

15. The receiver of claim 14, wherein the altitude information includes an altitude and an altitude uncertainty.

16. The receiver of claim 15, wherein the altitude comprises a first altitude from a given reference point associated with the earth, and the altitude uncertainty comprises a given deviation from the first altitude.

17. The receiver of claim 14, wherein a boundary of the modeled region is defined by an interconnection of a number of coordinate-system points that together delineate the modeled region.