iPhone GPS

[gdog]

Recently got myself an iPhone. Playing around with the GPS has being pretty sweet. And I noted the available ...um.... "mod" from Wombat_Australia (GPS on the Iphone).

The iPhone is an "Assisted GPS" device (A-GPS). As I haven't yet had the chance to play with the iPhone out in the bush, away from any phone signal, I was wondering if anyone else has and how did you find it? - Could it be used as a real GPS or is it really just a 'suburban' unit?

[Wombat_Australia]

I will be able to tell you if it is any good after the queens birthday weekend as my wife and I are heading up to the high country, be careful using the GPS option around town as it cost you data because it uses the wap to get its position, I learnt this after my first bill

[hotcty]

hey i have the iphone with the app motion-x gps......(buy the full one for $5ish bucks) or you can have the lite one for free. it works a treat out in the bush. it uses the phone towers only so that it gets a quicker signal lock. out in bunyip where you have no phone signal it works fine. sees all the satilites and knows where you are. just takes about 1min longer to find you thats all. you can log your tracks and upload them to here. only problem that i have with it is when you are in super dense bushland with a thick canopee is when it has trouble with the gps. only coz it has no external antanna.

[hotcty]

oh and motion-x gps doesnt need you to jailbreak you phone. its just an app and it works it has maps on it also but you need the phones mobile reception to get the maps downloaded. thats the only thing thats annoying me. i have the hema maps on my phone as folder of pdfs so i can see them... thats how i get my maps.

[bmurray2250]

The iphone should work if it has a true GPS unit in addition with the assist from the cells. The below URL and info should be able to answer your question.

Assisted GPS - Wikipedia, the free encyclopedia

In certain conditions, Conventional Standalone GPS has difficulty providing reliable positions in poor signal conditions. For example, when surrounded by tall buildings (resulting in multipath), or when the satellite signals are weakened when a GPS device is used indoors or under trees. Some newer receivers are better at handling these situations.

In addition, when first turned on in these conditions, some non-assisted GPS units may not be able to download the almanac and ephemeris information from the GPS satellites, rendering them unable to function until a clear signal can be received continuously for up to 40 seconds.

An A-GPS receiver can address these problems in several ways, using network elements such as either an assistance server or other data from a network. That assistance generally falls into two categories: a) information used to more quickly acquire satellites, or b) calculations done remotely:

* The assistance server can locate the phone roughly by which cell site it is connected to on the cellular network.
* The assistance server has a good satellite signal, and lots of computation power, so it can compare fragmentary signals relayed to it by cell phones, with the satellite signal it receives directly, and then inform the cell phone or emergency services of the cell phone's position.
* It can supply orbital data and/or almanac for the GPS satellites to the cell phone, enabling the cell phone to lock to the satellites faster in some cases.
* The network can provide atomic time (Accurate Time Assistance)
* Simply capturing a brief snapshot of the GPS signal, with approximate time, for the server to later process into a position.[2]
* By having accurate, surveyed coordinates for the cell site towers, it has better knowledge of ionospheric conditions and other errors affecting the GPS signal than the cell phone alone, enabling more precise calculation of position. (See also Wide Area Augmentation System)

[gdog]

hotcty - upon your recommendation, I downloaded and bought motion-x. Have to say - very sweet piece of software. I like it a lot. Thanks for the info on that one.

I'm yet to get completely away from civilization so the phone has no signal and test how it all goes. But that opportunity will be coming in the next few weeks. Thanks again.