Method of compressing GPS assistance data to reduce the time for calculating a location of a mobile device

• US 20070257838A1
• Filed: 11/28/2006
• Published: 11/08/2007
• Est. Priority Date: 12/22/2005
• Status: Abandoned Application

• Current Assignee: Spirent Communications Incorporated
• Original Assignee: Spirent Communications Incorporated
• Inventors: Cheng, Ming
• Application Number:
  US11/605,093
• Publication Number:
  US 20070257838A1
• Time in Patent Office: Days
• US Class Current: 342/357.420
• CPC Class Codes: G01S 19/05 providing aiding data
• CPC Class Codes: G01S 19/258 relating to the satellite constellation, e.g. almanac, ephemeris data, lists of satellites in view

Abstract

The invention relates to global positioning system (GPS) assistance data, and in particular, an embodiment in which a method of compressing GPS assistance data reduces the time to transmit data and also reduce time to calculate a location for a mobile device, such as a wireless telecommunications device. The method is especially-well suited for satellites have similar Almanac and/or Navigation Model information elements. The time for a Serving Mobile Location Centre (SMLC) to transmit the compressed assistance data to the mobile device is thus reduced. This eventually reduces the total time for a mobile device to calculate its location based on the assistance data information. Hence the time to first fix (TTFF) which is the time to calculate the first “fix” (also known as the first calculated location) is reduced.

Claims

1. A method of reducing total time for calculating a location of a mobile device using assisted global positioning system data from at least two satellites with similar information elements, the method comprising the steps of:

a) collecting a first element data set from a first satellite;

b) collecting a second element data set from a second satellite;

c) summing the element data set collected from the first satellite;

d) determining a third element data from the collected first element data and the collected second element data set by determining the difference between the collected first element data set and the collected second element data set;

e) summing element data of the third determined element data;

whereby the summed third determined element data is compressed assistance data that is used to determine a location of a mobile device.

2. The method as claimed in claim 1 whereby the first and second element data set from the first satellite is Almanac element data.

3. The method as claimed in claim 1 whereby the first and second element data set from the first satellite is Navigation Model element data.

4. The method as claimed in claim 1 whereby the location of a mobile device is determined using the summed third determined element data and a triangulation calculation.