New N95 firmware enables AGPS support, who is doing the assisting?
By Stefan Constantinescu on Thursday, June 21st, 2007 at 6:23 AM PST In Nokia
Symbian Guru Ricky got his hands on the latest internal Nokia (NYSE: NOK) N95 firmware, biggest feature upgrade: assisted global positioning. What makes AGPS different from standard GPS?
Standard GPS works without the need to be connected to a network of any kind. The stuff you see in cars, boats, the Nokia N95 before today’s firmware, they all had to sync with at least 3 satellites in line of sight to get a fix and then process data. This takes time, a lot of time. When I was trialing the N95 a couple of months ago I got the GPS to get a fix only once. Sure GPS chips are getting better and faster, but how else can this lock on speed be enhanced? This is where AGPS comes in.
The A in AGPS stands for assisted. Your mobile takes a snapshot of what current satellites are visible and talks to a server that knows where the closest cell phone towers are. The server calculates your exact location and spits it back out to your device. Wicked wicked fast. I had the pleasure of working at Helio, all of their devices have AGPS. Lock on time was less than 5 seconds and I hope Nokia can get there one of these days.
How can Helio do it so quickly, yet Nokia can’t? Helio knows the exact coordinates of all their (Sprint (NYSE: S)’s) cellphone towers. Nokia doesn’t have that luxury, but this is where users like Ricky and other N95 owners come in. Now this is just a theory, but I think that once the GPS finds your location it scans for nearby cellphone towers. This information is then sent to Nokia’s central database where they are slowly, but surely, creating a map of cell towers all around the world.
AGPS used to be something that was operator dependent, now Nokia might be turning the tables and making it hardware vendor dependent as well. What can Nokia do with this database? Lisence it and make money.
Excellent news.
They could license it, or, they could use it to add A-GPS to everyone of their phones, via firmware update. Which is brilliant.
And yes, they’ve got their own server, but there’s a place in the phone settings to change the server if you want.
I’m thinking that is in there so operators can use their own AGPS servers with the device.
Any word on the costs per data transfer? Or rather the amount in KB, as data plans may vary, of course?
I believe that it uses the Cell-ID which is listed on the tower and gives a relative location back. They have to actually learn the network though … so it should get even better over time.
A-GPS works a little differently to what you are describing in this article. A GPS fix is made up of a couple of steps (simplified). First the receiver has to determine where it is on the planet roughly so that it knows what GPS satellites it should be getting a signal from – this satellite positioning information is called ephemeris data and takes a good chunk of the fix time to get hold of. With A-GPS it is this ephemeris data that is being sent to the handheld device based on the rough position of the cell tower(s) you are connected to – no complicated cell tower based technology is being used to position the device. However, because the ephemeris data is served up quickly the device gets straight onto some complex integration of signals from the known satellites to determine exact position and altitude (if you have 4 or more satellites in view). Hope that demystifies the process for readers out there.
well i guess i’ll have to wait till there is an update out of firmware version 12.0.013 until i can check out a-gps. the keystroke bug just seems to be too annoying in version 12.0.013..
regards,
sal
http://sal-one.com/