JITSPA: CORTxT’s patented Just in Time Satellite Position

Aiding “JITSPA” consumes much less data than traditional GPS aiding.

Traditional GPS aiding works by providing the targeted GPS device a file containing many days of GPS satellite orbital predictions. The aiding file is large because it contains 8 sets of orbital predictions per day with each defining 15 high precision coefficients for up to 32 satellites (3840 coefficients for each day).

By contrast, JITSPA reduces the data to 9 coefficients for 6-12 visible satellites (54-108 coefficients). This data is small enough to fit in 1 or 2 SMS messages, reducing the need for a data plan on the mobile phone. Software on the mobile phone then expands the small set of JITSPA data into the equivalent large GPS aiding file that the GPS is expecting. This file is only valid for about 1 minute near that region, after which the accuracy begins to degrade. During this time, the GPS will be able to download the true orbital prediction data from the satellites themselves, to continue with accurate locations.

1. SUPL Method:

System directs all SUPL aiding requests to a locally hosted (on handset) JITSPA SUPL server. JITSPA will generate aiding data then reply with SUPL responses back to the requester.

2. Direct Aiding:

Use JITSPA as a proxy whereby all location requests would be passed through JITSPA to the GPS untouched. JITSPA would use the detected location request to trigger the aiding request. JITSPA would inject the aiding directly into the GPS.

Patent granted March 2013

Methods and apparatus for providing location data with variable validity and quality
http://patentimages.storage.googleapis.com/pdfs/US8396484.pdf