gps

With discussions and speculation about what features the new Treo 800w will have, the convoluted and very confusing issue of aGPS versus GPS naturally arises and which, if either, the 800w will include. So what is aGPS? How does it differ from real GPS if at all? We'll fill you in on the full skinny -- which sadly can be anything from "just e911" to "Better than standard GPS."

Read on to learn what all of these terms actually mean and what it means for Windows Mobile users in general as this technology spans CDMA and GSM across the U.S on every device.

aGPS vs. GPS: The Basics

Okay, first let's do the basic definitions: aGPS = assisted global positioning system, while just regular GPS is non-assisted.

So who's assisting and why does it matter? When you use a GPS system and you turn it on, it needs to find orbit and clock data for the relevant satellites, this in turn results in what is called TTFF, or Time To First Fix how long before you get your location pinpointed. This initial TTFF is often called a cold start and on SiRF III systems (the latest GPS systems available), it can take anywhere from 30 seconds to a couple of minutes to acquire a signal. That time is dependent on your location, amount of interference and horizon information: open fields are faster than canyons or urban environments where buildings can interfere with the satellite-receiver line of site.

But when you use assisted GPS this whole process is much faster. Very often cellular network towers have GPS receivers (or a base station nearby) and those receivers are constantly pulling down satellite information and computing the data. This data is then passed on to the cellular phone (when requested) and acts like a cheat since the relevant satellites to your location are already identified and all that GPS computations is handled by 3rd party computers. This is the result of such a system, to you the end user:

• Faster location acquisition
• Less processing power is required by the device
• Saves battery life
• Location acquisition indoors or in non-optimal environmental settings

Sprint describes how their system is supposed to work from their online FAQ:

Q: What is Assisted GPS? How do you find me if only two satellites are available?
A: To meet the defined industry standards, a precision location fix requires a minimum of three GPS measurements. The term "Assisted" refers to how Sprint network resources are used to provide a more robust measurement when only two satellites are visible.

• Precision fix in tens of seconds.
• Very High accuracy (typically 5m-50m).
• Line of sight to three satellites is not required as in regular GPS technology, but two satellites must be visible for a precise AGPS fix.
• GPS chipset required in device. (All Sprint phones sold since Jan 2002 have the GPS chipset. Contact your Sprint account representative for additional information.)

This is why many of us in the forums often cringe when someone suggests that having a standalone SiRFIII chip in a phone is preferable to an aGPS system, although the confusion is quite understandable and that brings us to our next point: the caveats.

Caveat #1: aGPS configurations

This story of aGPS so far seems fairly reasonable and straightforward, but alas it is not. See aGPS is not some monolithic, written-in-stone-standard. In fact, Qualcomm, who makes the most popular aGPS chips (called GPSOne) has four different possible configurations for aGPS. How aGPS is actually implemented on the device appears to be up to the device OEM/cellular carriers.

These four options are:

• Standalone - Your handset has no connection to the network, and uses only the GPS satellite signals it can currently receive to try and establish a location.
• MS Based - Your handset is connected to the network, and uses the GPS signals + a location signal from the network.
• MS Assisted - Your handset is connected to the network, uses GPS signals + a location signal then relays its 'fix' to the server, which then uses the signal strength from your phone to the network towers to further plot your position. You can still maintain voice communication in this scenario, but not 'Internet/Network service' ie Web Browser, IM, streaming TV etc..
• MS Assisted/Hybrid - Same as above, but network functionality remains. Normally only in areas with exceptional coverage.

Standalone mode is important. This means you do not need the carrier network at all to use GPS and usually you can install any GPS mapping software to boot. This is how the HTC Tilt and modern BlackBerries work and the Sprint Q9c (a review of which will be posted on WMExperts next week). Here there is virtually no difference between a standalone SiRFIII GPS system and a standalone (aka autonomous). The fact that the Sprint Q9c operates in standalone should be a sign of how Sprint plans to adopt aGPS systems in their Windows Mobile lineup (read here and here regarding possible updates for GPS for the Mogul and Touch). Interestingly, someone came up with a hack to enable the assistance servers for the Q9c to give all the benefits of a true aGPS system.

So which configuration of aGPS is important to how you can utilize the service. If it 100% relies on assistance-servers, then using it off-network is not an option, which may be the case with the BlackBerry 8830 (Sprint Worldphone):

Q  Does GPS work internationally?
A  No, the GPS chipset on the 8830 is disabled when the device is in GSM/GPRS mode due to Qualcomm requirement.

Caveat #2: The role of the mobile carriers

Now for the other shoe to drop: the carriers. Every modern cell phone has an aGPS chip on it because of the enhanced 911 requirement, which is also why you don't have many phones with a separate SiRFIII chip on board: it is redundant and expensive.

But on Sprint, Verizon and some other carriers like AT&T they have devices with aGPS on board that is not accessible to the end-user for any purpose except for e911 (like the ppc-6700 or the Treo 700wx). Now why this is the case is a matter of debate and a lot of speculation, which ranges from the carriers have purposefully disabled this feature to the APIs were not ready (API= Application Programming Interface) or maybe even a combination. Some have also suggested that these devices need an internal antenna plexed to the chip in order to gain a satellite signal, although since cheap flip phones on Sprint can do aGPS, this remains controversial. Regardless, the fact that simple flip phones could do aGPS for mapping and $500 WM phones cannot, rubbed many in the mobile community the wrong way.

The point of this caveat is that it is up to the carriers ultimately do decide on whether certain devices have:

• Full, autonomous aGPS that is user accessible
• Locked down or limited aGPS (e.g. what AT&T did recently with the BlackJack II)
• Non-accessible to the end-user at all

That last option, for whatever reason, is currently the most common but it at least appears that the carriers (except for maybe Verizon who is truly draconian) are moving towards the more open system.

Wrapping Up

Hopefully you have learned how aGPS can mean everything from it does nothing except for 911 to it is superior to traditional GPS. Where new WM devices fall on that spectrum is an ongoing adventure, but hopefully you now have the knowledge to ask the right questions:

• Is the aGPS autonomous?
• It is locked down (e.g. hidden COM ports)?
• Can it use assistance servers when

Having answers to those will allow you to better gauge what GPS or aGPS really means.

PS Feel free to bookmark or pass this article on to others to help dispel any confusion out there on the 'net ;-)

Well it looks like the Verizon Touch that surfaced last Friday is coming a might bit quicker than we expected, given that Engadget Mobile just scored a bunch of pics and details. Check out their Gallery to find out that, uh, it looks identical to the Sprint version (except for that white thing).

No word yet on what they'll be putting on the TouchFLO cube, but it does look like there's a shopping cart on the Today screen. In other words - expect it to be Verizon-alicious just like the Sprint Touch's cube is Sprint-app'ed up. Bummer, we were hoping for more customization - like, oh, a 4th side to the cube to add our own links.

Specs are out of the box too - EVDO (duh), WM6, 2 Megapixel camera, and the GPS is turned on in this one! Hopefully Sprint will follow suit on their version very soon, as expected.

When we had our hands-on with the BlackJack II a month ago, the AT&T reps at CTIA weren't exactly helpful on the subject of just what flavor of GPS was onboard - was it real or was it the tower-triangulation-fake-out kind. Well it's starting to look like it's really real for sure, at least according to the “coming soon” info now popping up on AT&T's website.

In one spot we see “GPS support,” but poking around more reveals “integrated GPS” and PDADB tells us it's SIRF III. Boom. Still no word on whether they've really managed to lock it down to just TeleNav (as was hinted to us at the CTIA conference), but let's hope not.

Otherwise the specs remain what we expected: slightly better than the original but not mind-blowingly better. You should be able to go get yours on Friday.

Oh, and AT&T - just one more thing. This doesn't count as the promised upgrade of the original Blackjack to Windows Mobile 6. We're all still waiting for that one. Remember us - your customers? You know, the ones who were disappointed when we thought it was delayed until Q3? (ah, if only we would have had it in Q3). Yeah, we're still here. Mmmhmm, yep, that's right, we didn't forget. You going to release that anytime soon?

It is now being rumored from DaSuper, a Sprint employee, over at The Buzz that Sprint will be releasing it’s first major ROM upgrade for the Mogul this month (one that does more than just add a music store) that will hopefully address the serious Bluetooth issues that have plagued the Mogul since it’s release.

Can it be true? Is the anticipated major ROM update for the Sprint Mogul (aka PPC-6800) really coming out before the end of this month (Oct 22nd to be exact)? If you are still waiting for Sprint’s promised ROM update for the PPC-6600 from over 2 years ago, then I understand if you have your fair share of doubts.  This was originally rumored to release by the end of last month, so only time will tell. 

There is a lot of hope these Bluetooth bugs will be fixed (if the ROM is truly released) as the port of Alltel PPC-6800 ROM seems to fix the Bluetooth issues all of us Mogul users face every day.   Is this going to history repeating itself with continual unfulfilled promises from Sprint for ROM updates or is DaSuper really onto the scoop of the year for everyone who owns a Mogul?

I've just confirmed that The ROM Update which addresses Bluetooth issues should be posted by 10/22 at [HTC's Mogul Update site]? The first update is currently posted on this website (Version 2.09.651.3_1.32.00), so in order to minimize confusion, users should not go to download the ROM Update until 10/22 or after.
[source]

To keep up to date if Sprint really follows through this time, keep an eye on the Mogul ROM Update Watch! in the discussion forums!

Update (from Dieter): DrDoom reports that folks "in the know" are saying that January or February is a more likely date. Bummer, that. *However*, said sources are also making vague rumblings about GPS (or maybe it's aGPS/gpsOne) being switched on for the Mogul, which we've reported on before and are thoroughly confused about. I Can Has GPS?

Pardon my rant:

I joined in the crowd talking about the FCC approval of the ho-hum HTC Iris because it's out there in the blogosphere and we here at WMExperts are super hip with the blogosphere, natch. However, I'm seeing it reported that the Iris has GPS. It does not. It has gpsOne. People: don't say a gadget (especially a rumored gadget that people might save up their pennies to buy) has GPS when it only has gpsOne.

What's the difference and what's my beef? Read on after the break.

What's gpsOne? Here's what Qualcomm says; here's Wikipedia:

gpsOne is primarily used today for Enhanced-911 E911 service, allowing your cell phone to relay your location to emergency dispatchers, one of the traditional shortcomings of cellular phone technology. Using a combination of GPS satellite signals and the cell towers themselves, gpsOne allows your location to be plotted with greater accuracy than traditional GPS systems in areas where satellite reception is problematic due to buildings or terrain.

Read: GpsOne - Wikipedia, the free encyclopedia

Basically here's the difference: GPS provides very accurate location information that you can use in various applications like Windows Live Search, TomTom, or Google Maps. GpsOne is locked down 95 times out of 100 so all it does is tell 911 dispatchers your approximate. In fact, many folks who have tried to unlock gpsOne capabilities have found it to be inaccurate and have even ended up making their phones dial 911 by mistake.

The situation is even worse on Windows Mobile, actually, because many WM devices could use those chips if there were an API and carriers allowed developers easy access to the gpsOne chip. If you've been holding your breath for carriers to do something nice for you, stop: they're never going to. It's especially aggravating because, as Sbono13 notes, gpsOne actually can work on certain plain-jane featurephone in conjunction with Google Maps. When will we see GpsOne available for apps on a Windows Mobile device? I'm going to guess never. It's sad, but not too sad, because at the end of the day gpsOne isn't as accurate at true-blue GPS anyway.

Look, I want GPS native on my Windows Mobile devices as much as, if not more than, the next guy. Witness my slathering over the upcoming AT&T Tilt. But until carriers allow that gpsOne data to be used openly (read: never), quit thinking the "gpsOne" tickmark on spec sheets means that GPS is built-in. You're just sowing confusion amongst users and raising everybody's hopes.

Meanwhile, pick yourself up a Bluetooth GPS Receiver instead. Me, I'm going to go take my blood pressure medication.

Dang, the headline say sit all. Somehow a company called Blue Sky Positioning has managed to fit a GPS receiver onto the little SIM cards that are normally just used to store your phone number and a few contacts. The most surprising part, to me, is they've managed to do it without breaking one of the GSM standard for SIM cards: that they never draw more than 6 milliamps of power.

The secret sauce seems to be that the card uses the body of the phone (i.e. the metal, battery, etc that surrounds it) as the antenna - which neatly solves what would otherwise be a huge interference problem.

I doubt this SIM solution will really take off, but it at least serves as evidence that GPS receivers are coming down in size and power requirement in a radical way. That bodes well for the inclusion of GPS in nearly all future handsets.

At the SIMposium in Berlin, Blue Sky Positioning announced it has developed a complete GPS system, including the antenna, which physically fits in, and works from within, a mobile phone SIM slot.

Read: Blue Sky squeezes GPS onto a SIM | The Register