I have a theory that the "GPS Enabled" feature of most recent model cell phones doesn't really work very well, if at all. This feature is really a survival issue, since many people rely on their cell phone as a way to contact rescuers in an emergency.

I've just gotten my second cell phone that is so-called "GPS Enabled". This one is the Treo 600, which is also a Palm Pilot. It would seem incredibly useful to have a moving map on it connected to that GPS. But it appears there is nothing in the software interface that allows a connection to the GPS, not on any GPS enabled cell phone. The GPS chip is there only to provide a location reference for a 911 call, as mandated by congress.

It seems so obvious that it would be useful to use the GPS from a software application on one of these phones that you wonder why they don't do it. I have a theory about that. It's because it basically doesn't work, and if they gave you applications that use it, you would find out that it doesn't work. It's only there to meet the letter of the law.

If you've used a GPS, you know how finicky the signal can be. If you have a GPS in your pocket, and pulled it out, what are the chances it has an accurate position? Pretty slim, in my experience. And the GPS chip on the phone is presumably not monitoring the GPS satellites all the time, that would suck up too much battery power. It takes a long time to establish a GPS position for all GPS units I've used, and they have an antenna specifically designed for a GPS. Also, combined GPS/Comm Aviation handhelds I've seen often lose GPS contact when the Comm is transmitting. Presumably, the GPS on the cell phone would be used when calling 911, and this transmission would further degrade the ability of the GPS to establish a postion.

I don't have any direct knowledge either way, I'm only speculating based on the above reasoning. Does anybody have any knowledge that can confirm or deny my theory? Has this system been tested?

I thought these were more for the advertisers to be able to track you than for emergency services. I thought I heard that from a friend that works for Sprint corp but I may be wrong. I have no written evidence to support this claim.

Brian, you're even more cynical than I am!

Hehehe. Not trying to start conspiracy theories. Although I can be quite cynical at times (dont get me started on black boxes in automobiles) <img src="/images/graemlins/grin.gif" alt="" /> IIRC he was talking about some technology they were working on where you would have personalized mini billboard ads w/ audio on your cell in airports and on busses, subways, bathrooms etc based on information already collected through the current means (credit cards, discount cards, etc) and then the phone would tell where you are so the appropriate ads would be dispalyed in the appropriate places. Also talked about things like showing appropriate ads on the phone itself based on your location... ie: you walk in the Sears and the current sale items are displayed on the phone.

Yes, it does actually work. I can't go into too many details, due to my employer.

There are different ways to do this either via GPS signals or by cell/sector determination. Many websites can explain this.

But during testing, your position can be determined down to 67 feet. The only place this is active is in Rhode Island currently and has actually saved a boater during a 911 call. The downside of this is that the PSAPs (Public Safety Answering Points) have to come up with the money to support these features and as we know, funding to the public services can be tough.

But as Brian stated targeted advertising is a way for the carrier to generate revenue due to the mandatory implementation of this.

I'll just say this. In the next short time, you can subscribe to a feature to track your fleet, find your phone and when you drive by Cabelas (or where ever) you might get an SMS saying "stop in now for 20% off any item". But you can always opt out of this.

But as you, I wish my Treo 600 could be used with a moving map. Working on that. <img src="/images/graemlins/grin.gif" alt="" />

--Chris

Motorola iDEN handsets on the NEXTEL system have the ability to output a NEMA data stream via the data cable to your computer for a moving map. There also is a java app available for a monthly charge (requires network coverage and GPS visibility) to give you turn by turn audio and visual (arrows) directions between useer selectable points. The test mode on the handsets allows a lat/long and velocity readout, in a pinch you can get a lot out of that if you had to, and that test mode (I think) works off-network, out of coverage

In all reality, the cell phones themselves could also be used as standalone two-way radios. That would help in remote areas that may not have adequate cell coverage. I'm not sure, but I think GSM is supposed to eventually eliminate that because of satellite coverage. But hey, wouldn't it be cool to be able to call your friends out in the middle of nowhere without a cell tower? Oh, you just broke your leg, all by yourself and calling for help for anyone to answer? You're dead. It's illegal to monitor cell phone transmissions (plus, they're digital), even for life threating emergencies!

OK, so this sort of thing IS coming out:

Review: Cell phone GPS works well (CNN)

So it's just taking awhile for them to develop applications.

And as I think about it more, some of the things that take a long time for a handheld GPS can be done quicker on a cell phone- you start with a known cell, so that limits your location to begin with. It can also download the satellite data from the cell system, which is much quicker than directly from the satellites. Or so I would guess. I don't know if that's really how it works, but that's how I'd design it.

I have a Nextel i530, which is supposedly GPS enabled, with NMEA output capability. The manual and associated software menus report to have user selectable "privacy controls" on the GPS software, but state that these are bypassed on 911 calls, and that the phone's location can always be made available to it's owner/administrator.

A fix recently came out from Motorola for the "A-GPS" (assisted global positioning system) featured in these handsets. I understand this to mean the iDEN network sort of "helps along" the GPS receiver when possible to acquire an initial position. Must've been a pretty serious bug as Motorola is now giving away the USB data cable along with a CD-ROM containing the software patch. They had been charging $30 up until recently for the cable alone.

FWIW, I've never, ever gotten the i530 to acquire a GPS signal, either before or after the software update...tried about a dozen times total. In the last few months the phone has been telling me the "satellite data is outdated, call 800-xxx-yyyy to buy". Guessing this is the almanac data, which, in theory would only mean it should take longer to get a fix. No joy there.

Let's just say i'm not counting on E911 being able to lock on to my position in an emergency, and I would definitely not substitute it for a real GPS unit.