Saturday, April 22, 2006

Cingular's GSM Assisted-GPS Implementation

I raised the issue a while back, before the BlueTooth adventure. I did look up TruePosition, which has a product called TrueNorth System that includes Cingular among its clients for PDE services for their GSM network.

From the website you get that TrueNorth provides "Position Determining Equipment (PDE), Serving Mobile Location Centre (SMLC) and Gateway Mobile Location Centre (GMLC) hardware and software [...] providing E-CID, A-GPS, U-TDOA and AOA."

U-TDOA is the one acronymn to look up from the list to understand the triangulation technique used here. And just to see how the pieces are putting themselves together: "TrueNorth is a subsidiary of Liberty Media Group with offices in U.K. and Sweden." [NYSE: L, LMC.B]


From an old issue of the Pulver Report: "Cingular is using E-OTD and CGI-TA (Cell Global Identity-Timing Advance, a low-accuracy fallback, accurate to about a kilometer) for GSM and is using TDOA for analog and TDMA."

And more interestingly:

"Cingular is deploying location technology solely to meet the FCC E911 mandate. They do not have plans to offer location-based services. One possible reason [...] suggested for this is that Phase II accuracy requirements are not particularly suitable for most services. For example, 100/300 m or even 50/150 m is insufficient for high-accuracy applications like turn-by-turn directions".

BTW, Jeff Pulver currently publishes a VOIP Report and is the one behind Vonage. Now he is doing the same for video.

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