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

• US 7,739,032 B2
• Filed: 03/21/2006
• Issued: 06/15/2010
• Est. Priority Date: 03/21/2006
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: van Diggelen, Frank
• Primary Examiner(s): To; Tuan C
• Application Number:
  US11/277,088
• Publication Number:
  US 20090066576A1
• Time in Patent Office: 1,547 Days
• Field of Search: 701/207, 701/200, 342/357.13, 342/357.09, 340/988, 340/991, 340/426.16, 340/426.19, 707/101
• US Class Current: 701/207
• 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. An apparatus for computing position, comprising:

a receiver operable to obtain pseudorange measurements at a location;

a terrain module operable to contain a regional-terrain model, the regional-terrain model including altitude information associated with a modeled region, wherein the modeled region defines its boundary as a function of a range of altitudes, and wherein the location is within boundary; and

a processor configured to

obtain from the regional-terrain model defined by the boundary as the function of a range of altitudes, the altitude information, and

compute a position of the location as a function of the pseudorange measurements and the altitude information.

2. The apparatus of claim 1, wherein the altitude information comprises an altitude and an altitude uncertainty.

3. The apparatus of claim 2, 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.

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

5. The apparatus of claim 4, wherein the boundary is defined by a point and a line segment.

6. The apparatus of claim 4, wherein the altitude information is used when a speed of the receiver is less than a threshold value.

7. The apparatus of claim 1, wherein the boundary is a function of the range of altitudes of the terrain.

8. A method for computing position, said method comprising:

obtaining pseudorange measurements at a location at a receiver;

storing a regional-terrain model, the regional-terrain model including altitude information associated with a modeled region, wherein the modeled region defines its boundary as a function of a range of altitudes, and wherein the location is within boundary at a terrain module; and

obtaining from the regional-terrain model defined by its boundary as the function of the range of altitudes, the altitude information, and

computing a position of the location as a function of the pseudorange measurements and the altitude information by a controller.

9. The method of claim 8, wherein the altitude information comprises an altitude and an altitude uncertainty.

10. The method of claim 9, 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.

11. The method of claim 8, wherein the boundary is defined by an interconnection of a number of coordinate-system points that together delineate the modeled region.

12. The method of claim 11, wherein the boundary is defined by a point and a line segment.

13. The method of claim 11, wherein the altitude information is used when a speed of the receiver is less than a threshold value.

14. The method of claim 8, wherein the boundary is a function of the range of altitudes of the terrain.