Device and method for calibrating and improving the accuracy of barometric altimeters with GPS-derived altitudes

• US 20040196176A1
• Filed: 04/16/2004
• Published: 10/07/2004
• Est. Priority Date: 04/12/2001
• Status: Active Grant

• Current Assignee: Garmin Limited
• Original Assignee: Garmin Limited
• Inventors: Olivier, Tracy, Burgett, Scott
• Granted Patent: US 7,142,152 B2
• Time in Patent Office: Days
• US Class Current: 342/120
• CPC Class Codes: G01C 21/20 Instruments for performing navigational calculations G01C21/24, G01C21/26 take precedence
• CPC Class Codes: G01C 25/00 Manufacturing, calibrating, cleaning, or repairing instruments or devices referred to in the other groups of this subclass testing, calibrating or compensating compasses G01C17/38
• CPC Class Codes: G01C 5/06 by using barometric means
• CPC Class Codes: G01S 19/14 specially adapted for specific applications
• CPC Class Codes: G01S 19/42 Determining position

Abstract

A portable, handheld electronic navigation device includes an altimeter and a GPS unit. An internal memory stores cartographic data, for displaying the cartographic data on a display of the navigation device. Accordingly, the device is capable of displaying cartographic data surrounding a location of the unit as determined by GPS and altitude information as determined by the barometric altimeter and GPS. The device provides an enhancement of the calibration and hence the accuracy of barometric altimeter measurements with the aid of derived altitudes from a GPS. The device is able to determine the need for calibration and perform the subsequent computations necessary to facilitate the calibration. Furthermore, the device is able to determine a correction quantity that should be applied to barometric altitude readings, thereby allowing the device to be calibrated while in motion. Both of these features ultimately result in a more accurate determination of altitude. In accordance with an aspect of the invention, the altimeter of the navigation device may be calibrated with altitude information entered by a user, with altitude information obtained from the cartographic, with altitude information derived from GPS or with any combinations thereof.

Claims

1. An electronic device comprising:

an altimeter comprising a barometric pressure sensor;

a GPS unit; and

a housing for housing said altimeter and said GPS unit, wherein said device is operable to calibrate said altimeter while said device is in motion.

2. The electronic device as set forth in claim 1, wherein the device continuously calibrates the altimeter.

3. The electronic device as set forth in claim 2, wherein the GPS unit is operable to determine an altitude of the electronic device.

4. The electronic device as set forth in claim 3, wherein the altimeter is operable to determine an altitude of the electronic device.

5. The electronic device as set forth in claim 4, wherein calibration of the altimeter accounts for any dynamic changes of the altitude as determined by the altimeter and the altitude as determined by the GPS unit when the altimeter and GPS unit are moved in tandem.

6. The electronic device as set forth in claim 1, wherein the housing is portable and handheld.