GNSS POSITIONING USING PRESSURE SENSORS

• US 20100204916A1
• Filed: 06/04/2008
• Published: 08/12/2010
• Est. Priority Date: 06/08/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Garin, Lionel J.
• Granted Patent: US 8,949,025 B2
• Time in Patent Office: Days
• US Class Current: 701/208
• CPC Class Codes: G01C 5/005 altimeters for aircraft G01C5/02, G01C5/06 take precedence
• CPC Class Codes: G01L 19/08 Means for indicating or recording, e.g. for remote indication
• CPC Class Codes: G01S 19/22 Multipath-related issues
• CPC Class Codes: G01S 19/45 by combining measurements of signals from the satellite radio beacon positioning system with a supplementary measurement

Abstract

Systems, methods and devices for improving the accuracy of GNSS data are provided. Specifically, embodiments of the invention can advantageously use sensor input to improve the accuracy of position fixes. The use of physical sensors in navigation systems is deemed particularly advantageous, especially where altitude data derived from the pressure sensor is calibrated with and/or blended with GNSS altitude data.

Claims

1. A navigation receiver, comprising:

a pressure sensor input;

circuitry coupled to the pressure sensor input; and

wherein the circuitry is configured to use information from the pressure sensor input to improve a position fix.

2. The navigation receiver of claim 1, further comprising a pressure sensor connected to the pressure sensor input;

and wherein the relative measurements of the pressure sensor are more accurate than the absolute measurements of the pressure sensor.

3. The navigation receiver of claim 1, wherein the navigation receiver comprises a GNSS receiver, and wherein the circuitry is configured to calibrate an altitude derived from the pressure sensor input using an altitude derived from the GNSS receiver.

4. The navigation receiver of claim 3, wherein the altitude derived from the GNSS receiver used to calibrate the altitude derived from the pressure sensor input has not been Kalman-filtered.

5. The navigation receiver of claim 3, wherein the circuitry comprises a central processing unit executing a position solution section, a velocity solution section, a Kalman filter and an atmospheric model section.

6. The navigation receiver of claim 2, wherein the circuitry coupled to the pressure sensor input is configured to derive a first altitude from the pressure sensor input;

and wherein the circuitry coupled to the pressure sensor input is configured to blend the first altitude with a second altitude derived from a GNSS sensor.

7. The navigation receiver of claim 6, wherein the circuitry coupled to the pressure sensor input is configured to carry out a complementary filter operation.

8. A method for improvement of GNSS positioning, comprising:

receiving a GNSS measurement;

deriving a first altitude from the GNSS measurement;

deriving a second altitude from a pressure sensor input corresponding approximately in time to the GNSS measurement; and

combining the first and second altitude measurements to obtain a blended altitude measurement.

9. The method of claim 8, wherein the step of combining the first and second altitude measurements comprises executing a complementary filter operation.

10. The method of claim 9, wherein the step of executing a complementary filter operation comprises filtering data related to the first altitude using a low-pass filter and filtering data related to the second altitude using a high-pass filter.

11. The method of claim 8, wherein the second altitude is derived using an atmospheric model.

12. A portable navigation system, comprising:

a GNSS sensor;

a pressure sensor; and

a microprocessor configured to use input derived from the GNSS sensor and the pressure sensor to provide a map location without using map-matching.

13. The portable navigation system of claim 12, wherein the navigation system provides a horizontal accuracy of 5 meters or less in an urban canyon environment.

14. The portable navigation system of claim 12, further comprising a machine-readable medium comprising software instructions that, when executed by the microprocessor, would perform a method comprising the steps of:

computing a GNSS altitude;

computing an altitude based on a measurement derived from the pressure sensor; and

combining the GNSS altitude and the altitude based on a measurement derived from the pressure sensor to produce a blended altitude.

15. The portable navigation system of claim 14, wherein the step of combining the GNSS altitude and the altitude based on a measurement derived from the pressure sensor comprises using a complementary filter.

16. A portable vehicle navigation system, comprising:

a GNSS sensor;

a pressure sensor; and

a microprocessor configured to use input derived from the GNSS sensor and the pressure sensor to provide a map location; and

wherein the portable navigation system can differentiate between two roads in a stacked road condition.

17. The portable navigation system of claim 16, wherein the vehicle navigation system provides a vertical accuracy of 5 meters or less under stacked road conditions.

18. The portable navigation system of claim 16, further comprising a machine-readable medium comprising software instructions that, when executed by the microprocessor, would perform a method comprising the steps of:

computing a GNSS altitude;

computing an altitude based on a measurement derived from the pressure sensor; and

combining the GNSS altitude and the altitude based on a measurement derived from the pressure sensor to produce a blended altitude.

19. The portable navigation system of claim 18, wherein the step of combining the GNSS altitude and the altitude based on a measurement derived from the pressure sensor comprises using a complementary filter.