Satellite radiolocalization receiver

• US 9,086,478 B2
• Filed: 06/04/2008
• Issued: 07/21/2015
• Est. Priority Date: 06/08/2007
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Cook, John Owen
• Primary Examiner(s): Keith, Jack W
• Assistant Examiner(s): McGue, Frank J
• Application Number:
  US12/599,249
• Publication Number:
  US 20100149035A1
• Time in Patent Office: 2,603 Days
• Field of Search: 342/357.65, 342/357.28, 342/357.42, 342/357.43
• US Class Current: 1/1
• CPC Class Codes: G01S 19/26 involving a sensor measurement for aiding acquisition or tracking

Abstract

The invention uses information gathered from a barometric pressure sensor, connected to a GNSS receiver, to choose an optimal acquisition strategy. In an example, the device of the invention includes a pressure sensor, which is sampled at low rate during power off phases, to store a pressure profile, and a processor programmed to detect the signature of a pressurized-cabin airliner. In this way the GPS receiver can determine if the unit has been flown during an inactivity period, and estimate the duration of the flight. The advantage lies in improving the user experience by shortening the Time to First Fix after air travel.

Claims

1. A satellite radiolocalization device, comprising:

a barometric pressure determination unit configured to determine pressure data inside a pressurized aircraft;

a memory configured to store the pressure data;

the radiolocalization device configured to detect a pressure pattern of the pressurized aircraft based in part on the stored pressure data, wherein the pressure pattern comprises a plurality of pressure readings over time;

wherein the satellite radiolocalization device is configured to estimate a duration of an air travel of the pressurized aircraft based on the pressure pattern, and to determine a position uncertainty based at least in part on the duration; and

wherein the satellite radiolocalization device is further configured to determine the position uncertainty based on the presence of said pressure pattern, the pressure pattern indicating (a) a phase of rapid initial pressure drop, (b) a phase of constant pressure, and (c) a phase of rapid pressure increase.

2. The satellite radiolocalization device of claim 1, wherein the satellite radiolocalization device is configured to detect coordinates of a registered airport at landing and estimate the position uncertainty based upon the coordinates.

3. The satellite radiolocalization device of claim 1, wherein the satellite radiolocalization device is further configured to estimate the position uncertainty based upon the pressure data at landing.

4. The satellite radiolocation device of claim 1, wherein the radiolocation device is configured to estimate the duration of the air travel using the duration of the phase of constant pressure.

5. A satellite radiolocalization device, comprising:

means for storing pressure data;

means for determining barometric pressure inside a pressurized aircraft in which the means for storing pressure data stores the pressure data from the means for determining barometric pressure, the radiolocalization device configured to detect a pressure pattern in the pressurized aircraft based in part on the stored pressure data;

wherein the satellite radiolocalization device is configured to estimate a duration of an air travel of the pressurized aircraft based on the pressure pattern, and to determine a position uncertainty based at least in part on the duration;

wherein the satellite radiolocalization device is further configured to determine the position uncertainty based on the presence of the pressure pattern, wherein the pressure pattern comprises a plurality of pressure readings over time, the pressure readings indicating (a) a phase of rapid initial pressure drop, (b) a phase of constant pressure and (c) a phase of rapid pressure increase; and

wherein the satellite radiolocalization device is configured to select a satellite search strategy based at least in part on the detected pressure pattern.

6. The satellite radiolocalization device of claim 5, wherein the satellite radiolocalization device is configured to detect coordinates of a registered airport at landing and estimate the position uncertainty based upon the coordinates.

7. A method for satellite radiolocalization comprising:

determining a barometric pressure inside a pressurized aircraft with a barometric pressure determination unit, with a memory configured to store pressure data when in a low-power mode;

placing the barometric pressure determination unit in the low-power mode;

storing the pressure data in the memory;

detecting a pressure pattern in the pressurized aircraft based in part on the stored pressure data, wherein the pressure pattern comprises a plurality of pressure readings over time, the pressure readings indicating (a) a phase of rapid initial pressure drop, (b) a phase of constant pressure and (c) a phase of rapid pressure increase;

estimating a duration of an air travel based on the pressure pattern; and

determining a position uncertainty based at least in part on the duration.

8. The method of claim 7, further comprising detecting coordinates of a registered airport at landing, and estimating the position uncertainty based upon the coordinates.

9. A non-transient computer readable medium comprising program code configured to:

determine pressure data inside a pressurized aircraft with a barometric pressure determination unit comprising a low-power mode;

place the barometric pressure determination unit in the low-power mode;

store the pressure data in a memory;

detect a pressure pattern in the pressurized aircraft based in part on the stored pressure data;

estimate a duration of an air travel based on the pressure pattern;

determine a position uncertainty based at least in part on the duration; and

select a satellite search strategy at an end of the low-power mode based at least in part on the detected pressure pattern.

10. The computer readable medium of claim 9, further comprising program code configured to detect coordinates of a registered airport at landing, and estimate the position uncertainty based upon the coordinates.