Hi,

I would like to know why my $100 car navigation is Sirf III
and I get fix fast and gps in N810 , iPhone is still aGPS
as no-aGPS is slow ?
Why not to put $10 Sirf III chip into iPhone, N810
and have fast fix and strong signal ?

I have got Motorola A1000 3 years ago and itr featured AGPS.
Fix very slow as showed no interest to have my A1000 to connect via gprs to get gps fix faster at some extra cost.

It was 3 years ago.
What makes Nokia, Apple to still offer old AGPS not Sirf III GPS solution ?
Sirf III fast fix, strong signal GPS chip is $10 only
and no need to pay any charge to telecom operator to get a fix.

New 3G iPhone was already marketed as full GPS cell phone/PDA
and failed.
Skyhook (no GPS navigation is still in operation).
Fix based on triangulation algorithm, not reading satelite gps data.

What is a problem to put $10 Sirf III chip into N810, iPhone 3G ?
I was all for new iPhone but don't want old AGPS solution.

Darius

probably price, size, battery life and general avaibility

You're mixing up a couple of things, hopefully accidentally. AGPS is not a chipset like Sirf, it's a way to assist the selected chipset with cell signals. Many SIRF based solutions also use AGPS additionally to improve performance. iPhone is using the Broadcom chip and AGPS.

http://seekingalpha.com/article/4774...ps-partnership

Or:
http://artoftheiphone.com/2008/06/10...-assisted-gps/
"The main advantage of Assisted GPS (AGPS) for the iPhone is that it will allow the iPhone’s GPS to operate in weaker signal conditions and determine positioning quicker than most standalone GPS receivers. AGPS also helps save battery power by handing off some computational duties to an assistance server and by allowing iPhone users to turn GPS off and on with less inconvenience."

As to why AGPS is needed in mobile devices whilst not really in cars,

cars are not generally driven indoors.

I don't buy such explanation.
There is a number of fast fix, strong signal gps enabled PDA, cell phones, already on a market.
AGPS means exactly what it means.
No intelligent Sirf III or better fast fix, strong signal chip installed
so assistance required.

To get a fix on my Motorola A1000 AGPS in non-assisted mode
it took sometimes one hour or more.
Assistance server like Skyhook for iPhone is database of geocoded cellular base stations, wifi spots, basing computions on a triangulation algorithm (signal level received).

As I can use my $100 full gps car navigation on the go to get fix in
15-20 sec I still see no reason to implement old solution like agps
into new product.

Just enter into Google search : cell phone + Sirf III
to see, AGPS has gone, as an alternative solution in times, Sirf III chip was not available.

Darius

No, Ragnar is correct. The problem with the GPS in the N810 has nothing whatsoever to do with AGPS or no AGPS. The problem is simply that as a GPS receiver the TI chipset in the N810 is not as good as e.g. Sirf star III or the MTK (sp?) chipsets.

Assisted GPS is just a way of feeding pre-loaded and pre-received data to the GPS, to save time (time that would otherwise be spent waiting for initial data from satellites) and, less important, some power (for using the data to calculate some stuff). AGPS can be useful with any GPS, including the fast, mega-multi-channel ones.

As for 15-20 seconds lock time: You can't guarantee a lock time that fast if you start from cold conditions. With AGPS and a chipset like Sirf III you could get 1 sec lock time at all times, for example.

Again, the problem with the N810 GPS is that the chipset isn't that good. AGPS makes it less bad. However, the TI chipset probably uses less battery than a Sirf Star III would (not that the latter one is bad in that respect though).

Bet you can't if you move it a long distance or leave it switched off for 6 weeks or so. Obviously, unless you have a built-in phone or wifi network in your car, that device will not often have access to the assitance data it would need to make it faster.

AGPS should really produce ~1s fixes, we are just blessed by a crappy chipset in our N810s

i fully agree with the explanation that TA provided above. I just came back from vacation on the big island of hawaii (very cool and very big island) my wife and i got lost in the middle of the island (dont ask how - it just happened- and whatever you do dont believe my wife when she says it was my fault) but i digress- i remember i had my n810 in my cargo shorts- fired it up and w/i a minute had a route back to our rented condo- (i was using the paid for wayfinder app)- of course i had previously received a fix when i got to the condo so the aGPS knew where i was-

my wife*now* approves of my toy....

Warning, offtopic:

In the middle of the island there is a valley between two volcanoes. AFAIK, there is only one major road there... (or was ~10 years ago when I was there...) How did you get lost in there?

Did you try driving on the top of the Mauna Kea. They said only 4x4 should go there but we drove there with a rental Sunfire... Close to the top the air was so thin that with gas floored it barely made it there... We didn't spent much time there since we didn't want to get mountainsick (terrible headache...). The scenery was strange.. like moon surface?

way offtopic
bbut my wife's version of events hasnus nin a ford conv mustang in hilo (east side of island) we wered staying near kona on west side and i thight we were on way to active lava flow also on east side when (as wife puts it- i screwed up) we ended up on saddleback road (the road which you spoke of) but i did not know where we were the n810 got us home

my photos @ flickr (same name as here) do not do the island justice