Service Providers Boost GPS Navigation Data

Broadcom's Location Gambit

One provider of assisted GPS is Broadcom, the big U.S. silicon manufacturer whose inventory includes GPS chips. It's sort of like Starbucks buying a burlap-sack company to make sure there are enough bags to transport all those coffee beans. Other providers include Andrew Wireless Solutions, a division of CommScope, with its Geometrix MLC service, and TeleCommunication Systems (TCS), with its Xypoint service.

Broadcom's WorldWide Reference Network was originally launched in 2000, created by Global Locate, which was itself an early GPS chip start-up. Global Locate realized it needed a reference network to create a reliable, consistent and fast source of orbit tracking data if the chips were actually to deliver the goods, says David Murray, director of marketing with Broadcom's GPS products group. Murray was deeply involved in Broadcom's $143 million acquisition, finalized in June 2007.

Broadcom's network consists of a global chain of GPS receivers at ground stations, clustered around the earth's equator. The company won't say how many receivers or stations it has, only that there are at least three receivers tracking at all times each of the 28 satellites now in orbit, according to Murray.

The receivers constantly monitor the GPS satellites and track their orbits, feeding data in real time to two redundant servers, one in New Jersey, one in New York, run by a third-party data center operator. Today, about 20 million devices of various types access this data via an IP connection, eliminating the slow process of satellite hunting, and creating almost immediate fixes.

Broadcom charges for the service, which is usually bought by carriers or handset makers, and which works with other brands of GPS chips. The service pays for itself, but Broadcom won't disclose revenues or profits. "Our plan is to make money off of this business," says Murray.

How It Works

Here's how it works. A fleet driver needs to find the closest service station that has a contract with his company for diesel fuel. He pulls out his company smartphone, and presses an icon to load Google Maps. The phone has a small application that uses an industry protocol, Secure User Plane Location (SUPL), to access the Broadcom reference network via an IP connection, and request the orbital data. That typically takes eight to 10 seconds, according to Murray. Once it knows where to find the satellites, the GPS chip can get the range and timing data it needs in a couple of seconds.

That speed and reliability is critical. Murray points out that 2G cellular networks support e911 emergency calls by using a triangulation technique based on cell phone tower signals to calculate a rough location. But 3G networks use the much more precise GPS, which can narrow the position to within a few meters. Broadcom supports both techniques, part of a plan to create a service that eventually will automatically use several techniques to locate a mobile device, depending on the precision needed and on the availability of the various techniques.

As part of this plan, Broadcom recently announced a deal with Skyhook Wireless, which has a database of tens of millions of Wi-Fi access points, and software that quickly calculates a Wi-Fi user's position in relationship to them, within a 30-to-60-foot range. Wi-Fi positioning will shortly be offered as an additional location option in the Broadcom service. Eventually, says Murray, Broadcom will integrate Skyhook with its own GPS chips and reference network infrastructure, enabling devices to use one integrated, hybrid positioning system.

The reference network also uses the data it stores to run complex mathematical models that can accurately predict where each satellite will be up to seven days in advance (Broadcom is working to extend that to 30 days). The models factor in such variables as tides, which can shift satellite orbits by many meters, says Murray.

This predictive data creates an intriguingly paradoxical element of the reference network. Customers can download this predictive data from a Web site and use it whenever they lack a data connection to the reference network. This data works as a kind of virtual satellite system conjured by mathematics.