Self-calibrating barometer

• US 7,637,141 B2
• Filed: 02/28/2007
• Issued: 12/29/2009
• Est. Priority Date: 02/28/2007
• Status: Expired due to Fees

• Current Assignee: Quartex Division of Primex Incorporated
• Original Assignee: Quartex Division of Primex Incorporated
• Inventors: O'Neill, Terrence J.
• Primary Examiner(s): Raevis; Robert R
• Application Number:
  US11/680,213
• Publication Number:
  US 20080202234A1
• Time in Patent Office: 1,035 Days
• Field of Search: None
• US Class Current: 73/1.59
• 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

Abstract

Methods and systems for adjusting a pressure value to account for an altitude-induced pressure effect. One method includes determining an average pressure value experienced at a first altitude, determining a ratio based on the average pressure value and a reference pressure value, determining a current pressure value experienced at the first altitude, and adjusting the current pressure value based on the ratio to obtain an altitude-adjusted pressure value.

Claims

1. A method of adjusting a pressure value of a pressure sensing device to account for an altitude-induced pressure effect, the pressure sensing device including a pressure sensing module and a processor, the method comprising:

determining, by the processor, an average pressure value experienced at an altitude, the altitude being unknown to the pressure sensing device, the pressure sensing module, and the processor;

determining, by the processor, a ratio based on the average pressure value and a fixed reference pressure value;

determining, by the pressure sensing module, a current pressure value experienced at the altitude; and

adjusting, by the processor, the current pressure value based on the ratio and independent of the altitude to obtain an altitude-adjusted pressure value.

2. The method of claim 1, wherein the average pressure value is a rolling average pressure value.

3. The method of claim 1, wherein the average pressure value is determined over a period of time including at least a plurality of days.

4. The method of claim 1, wherein the fixed reference pressure value is a theoretical average pressure value experienced at sea level.

5. The method of claim 1, wherein adjusting the current pressure value includes multiplying the current pressure value by the ratio.

6. The method of claim 1, wherein the altitude-adjusted pressure value is a barometric pressure value.

7. The method of claim 1, further comprising estimating the altitude based on the ratio.

8. A system for adjusting a pressure value to account for an altitude-induced pressure effect, the system comprising:

a pressure sensing module for determining a plurality of past pressure values experienced at an altitude and a current pressure value experienced at the altitude; and

a processor for determining an average pressure value based on the plurality of past pressure values, determining a ratio based on the average pressure value and a fixed reference pressure value, and adjusting the current pressure value based on the ratio and independent of the altitude to obtain an altitude-adjusted pressure value,

wherein the altitude is unknown to the system, the pressure sensing module, and the processor.

9. The system of claim 8, wherein the pressure sensing module includes at least one of a water-based pressure sensing device, a mercury-based pressure sensing device, an aneroid pressure sensing device, and an electronic sensing device.

10. The system of claim 8, further comprising a housing, wherein the pressure sensing module and the processor are positioned within the housing.

11. The system of claim 8, further comprising a memory module for storing the plurality of past pressure values.

12. The system of claim 11, wherein the memory module stores the ratio.

13. The system of claim 11, wherein the memory module stores the altitude-adjusted pressure value.

14. The system of claim 8, wherein the average pressure value is a rolling average of the plurality of past pressure values.

15. The system of claim 8, wherein the average pressure value is determined over a period of time including at least a plurality of days.

16. The system of claim 8, wherein the fixed reference pressure value is a theoretical average pressure value experienced at sea level.

17. The system of claim 8, wherein the processor adjusts the current pressure value by multiplying the current pressure value by the ratio.

18. The system of claim 8, further comprising at least one display for displaying the altitude-adjusted pressure value.

19. The system of claim 8, wherein the altitude-adjusted pressure value is a barometric pressure value.

20. A computer-readable medium in a pressure sensing device including a pressure sensing module and a processor, the computer-readable medium encoded with a plurality of processor-executable instructions for adjusting a pressure value to account for an altitude-induced pressure effect, the instructions comprising:

determining, by the processor, an average pressure value experienced at an altitude, the altitude being unknown to the pressure sensing device, the pressure sensing module, and the processor;

determining, by the processor, a ratio based on the average pressure value and a fixed reference pressure value;

determining, by the pressure sensing module, a current pressure value experienced at the altitude; and

adjusting, by the processor, the current pressure value based on the ratio and independent of the altitude to obtain an altitude-adjusted pressure value.

21. The computer-readable medium of claim 20, wherein the average pressure value is a rolling average pressure value.