NAVSOP Navigation System Rivals GPS

dangle writes "BAE Systems has developed a positioning solution that it claims will work even when GPS is unavailable. Its strategy is to use the collection of radio frequency signals from TV, radio and cellphone masts, even WiFi routers, to deduce a position. BAE's answer is dubbed Navigation via Signals of Opportunity (NAVSOP). It interrogates the airwaves for the ID and signal strength of local digital TV and radio signals, plus air traffic control radars, with finer grained adjustments coming from cellphone masts and WiFi routers. In any given area, the TV, radio, cellphone and radar signals tend to be at constant frequencies and power levels as they are are heavily regulated — so positions could be calculated from them. "The real beauty of NAVSOP is that the infrastructure required to make it work is already in place," says a BAE spokesman — and "software defined radio" microchips that run NAVSOP routines can easily be integrated into existing satnavs. The firm believes the technology could also work in urban concrete canyons where GPS signals cannot currently reach."

Comments

Re:Doesn't sound that accurate

[evilviper]

This can only work if you have a DB of precise locations of wireless signals. Even assuming that is viable, it cannot replace GPS as is.

Whenever a program is looking-up the location of a smartphone, that phone is very probably also beaming back a list of all the Wifi APs in-range, their signal strength, and approximate location. Everyone who makes navigation software for smartphones is guaranteed to have such a database, and is continually keeping it up-to-date.

Not only is it practical to do this, and it has been for years and years, it's done because you're likely to get much better accuracy, and a much quicker location fix. You can prove this out by running a navigation app on a tablet that has wifi but lacks a GPS chip. You'll find that Google Maps or anything else has no problem at all pinpointing your location.

And BTW, moving one AP won't cause a problem... Triangulation requires several APs in range, and it'll try to use everything in-range to get a more precise fix so... Short of conspiring to have everyone in an area to move their APs in unison for a significant distance, you're not going to significantly fool the algorithm that handles all of this.

What's more... Before wifi was widespread, the previous fallback was a database with the GPS coordinates, altitudes, power levels, etc., of all of a telco's cell towers. It works, but not as well as the horde of prolific wifi APs these days. And for the record, I am speaking from first-hand knowledge.