USING MAGNETOMETER WITH A POSITIONING SYSTEM
First Claim
1. A method comprising:
- determining an approximate latitude of a mobile station using a mobile station processor based on at least one feature of the Earth'"'"'s magnetic field measured by the mobile station;
determining an approximate longitude of the mobile station using the mobile station processor; and
storing the approximate latitude and the approximate longitude and using the approximate latitude and the approximate longitude in the search for satellites in a satellite positioning system (SPS) that are visible to the mobile station during search and acquisition of satellite signals for a position fix.
1 Assignment
0 Petitions
Accused Products
Abstract
A mobile station determines an approximate latitude using a measured feature of the Earth'"'"'s magnetic field. An approximate longitude may also be determined. The mobile station uses the approximate latitude and longitude, if determined, to assist in determining a position fix for the mobile station, e.g., by determining a list of visible satellites in a satellite positioning system (SPS) during search and acquisition of satellite signals and/or using the approximate position as a seed position in the position computation. The feature of the Earth'"'"'s magnetic field may be, e.g., inclination or vertical intensity, and may be determined using data from a three-dimensional magnetometer and a three-dimensional accelerometer. An instantaneous value of the magnetic field feature may be averaged to reduce the affects of motion and the presences of large metallic masses.
-
Citations
40 Claims
-
1. A method comprising:
-
determining an approximate latitude of a mobile station using a mobile station processor based on at least one feature of the Earth'"'"'s magnetic field measured by the mobile station; determining an approximate longitude of the mobile station using the mobile station processor; and storing the approximate latitude and the approximate longitude and using the approximate latitude and the approximate longitude in the search for satellites in a satellite positioning system (SPS) that are visible to the mobile station during search and acquisition of satellite signals for a position fix. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
-
-
15. A mobile station comprising:
-
a three-dimensional magnetometer; a three-dimensional accelerometer; a satellite positioning system receiver; a processor connected to receive data from the satellite positioning system receiver, data from the three-dimensional magnetometer and data from the three-dimensional accelerometer; memory connected to the processor; and software held in the memory and run in the processor to determine a value of the at least one feature of the Earth'"'"'s magnetic field using the data from the three-dimensional magnetometer and the data from the three-dimensional accelerometer and to determine an approximate latitude using the value of the at least one feature of the Earth'"'"'s magnetic field, and to use the approximate latitude in the search for satellites in a satellite positioning system (SPS) that are visible to the satellite positioning system receiver during search and acquisition of satellite signals for a position fix. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
-
-
27. A mobile station comprising:
-
means for measuring at least one feature of the Earth'"'"'s magnetic field; means for determining an approximate latitude of the mobile station using the measured at least one feature of the Earth'"'"'s magnetic field; means for determining an approximate longitude of the mobile station; and means for using the approximate latitude and the approximate longitude in the search for satellites in a satellite positioning system (SPS) that are visible to the mobile station during search and acquisition of satellite signals for a position fix. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36)
-
-
37. A computer-readable medium including program code stored thereon, comprising:
-
program code to determine the value of at least one feature of the Earth'"'"'s magnetic field using magnetometer data referenced to a local vertical direction; program code to determine an approximate latitude mobile station using the value of the at least one feature of the Earth'"'"'s magnetic field; and program code to use the approximate latitude in the search for satellites in a satellite positioning system (SPS) that are visible to the mobile station during search and acquisition of satellite signals for a position fix. - View Dependent Claims (38, 39, 40)
-
Specification