Navigation system with dynamically calibrated pressure sensor

• US 8,332,137 B2
• Filed: 12/04/2007
• Issued: 12/11/2012
• Est. Priority Date: 12/04/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Venkatraman, SaiPradeep, Garin, Lionel, Liu, Quanwei
• Primary Examiner(s): Mawari, Redhwan k
• Application Number:
  US11/950,207
• Publication Number:
  US 20090143983A1
• Time in Patent Office: 1,834 Days
• Field of Search: 701/3, 701/7, 701/207, 701/213, 701/214, 342/120, 342/121, 342/174, 342/450, 342/357.25
• US Class Current: 701/408
• CPC Class Codes: G01C 21/28 with correlation of data from several navigational instruments
• CPC Class Codes: G01C 5/06 by using barometric means

Abstract

A navigation system includes a pressure sensor, a calibration module in communication with the pressure sensor, and an altitude module in communication with the calibration module. The calibration module is configured to determine a dynamic pressure proportionality coefficient based at least in part on a static pressure proportionality coefficient, a measured pressure value from the pressure sensor, and a velocity value. The altitude module is configured to calculate a sensor-based altitude value based at least in part on the determined dynamic pressure proportionality coefficient.

Claims

1. A navigation system comprising:

a pressure sensor;

a calibration module configured to be in communication with the pressure sensor and configured to determine dynamic pressure model information based at least in part on at least three parameters, the at least three parameters including;

static pressure model information,

a measured pressure value from the pressure sensor, and

a velocity value of the navigation system;

an altitude module in communication with the calibration module and configured to calculate a sensor-based altitude value based at least in part on the determined dynamic pressure model information; and

a global navigation satellite system chipset configured to provide a received altitude value to the calibration module;

wherein the calibration module is further configured to determine a static pressure proportionality coefficient based at least in part on;

a received altitude value; and

a second measured pressure value from the pressure sensor.

2. The navigation system of claim 1, wherein the static pressure proportionality coefficient is determined during a static condition.

3. The navigation system of claim 1, further comprising a filtering module configured to:

receive the sensor-based altitude value from the calibration module; and

receive a global navigation satellite system (GNSS)-based altitude value from the global navigation satellite system chipset; and

combine the sensor-based altitude value and the GNSS-based altitude value to create an overall altitude value, wherein the overall altitude value is based at least in part on a noise characteristic of the GNSS-based altitude value.

4. The navigation system of claim 1, wherein the velocity value is received from at least one of the global navigation satellite system chipset or a dead reckoning system.

5. The navigation system of claim 1, further comprising a detection module configured to identify a change in the dynamic pressure proportionality coefficient.