Apple iPad: Does it have 'real' GPS? (updated: yes and no)
Summary: There's a debate that's raging over the "Assisted GPS" (A-GPS) features that's included in the iPad. It's unclear as to whether the iPad includes a dedicated GPS chip or whether it's using Assisted GPS to simulate "real" GPS.
There's a debate that's raging over the "Assisted GPS" (A-GPS) features that's included in the iPad. It's unclear as to whether the iPad includes a dedicated GPS chip or whether it's using Assisted GPS to simulate "real" GPS. Or something else completely
Here's how Wikipedia describes A-GPS, for context:
Conventional or "standalone" GPS operation uses radio signals from satellites. In very poor signal conditions, for example in a city, these signals may suffer multipath where signals bounce confusingly off buildings, or be weakened by passing through walls or tree cover... An A-GPS system can address these problems in several ways, using an assistance server or other data from a network.
The iPad tech specs clearly list (under Location):
Assisted GPS (Wi-Fi + 3G model)
Update: Looking closer at the "Wireless and cellular" category in Apple's iPad tech specs. "Wi-Fi model" is one configuration and "Wi-Fi + 3G model" is the other. From the Location section it could be interpreted that Assisted GPS is included in the Wi-Fi and 3G models (meaning both) but Apple actually uses the plus-sign in "Wi-Fi + 3G model" to mean the high-end, 3G model). Apple's marketing took some liberties with the plus-sign. So, to clarify, the 3G model has GPS and the Wi-Fi model doesn't have GPS.
So... is it a dedicated GPS chip, a combined chip (i.e. part of Apple's A4 or 3G chips) or is it using A-GPS as pseudo-GPS?
Interestingly enough, the tech specs for the iPhone 3GS (first column, also under Location) also list it as having "Assisted GPS."
Put another way: does the iPad ship with the same GPS functionality as the the iPhone 3GS?
The iPad tech specs clearly states that A-GPS is available on both the Wi-Fi and the 3G iPads, pretty much nullifying the argument that GPS is somehow included in the 3G chip. Although its conceivable that Apple could add extra GPS-specific silicon to the WiFi model, but it seems unlikely.
Post your take in the TalkBack.
Kick off your day with ZDNet's daily email newsletter. It's the freshest tech news and opinion, served hot. Get it.
Talkback
Assisted != Simulated
<i>superset</i> of GPS: It uses GPS but <i>may</i>
enhance the precision using other sources.
I think that the iPad has several glaring
omissions, but GPS is not one of them.
A-GPS
Specs are clear - it's got GPS
Wi-Fi
Digital compass
Assisted GPS (Wi-Fi + 3G model)
Cellular (Wi-Fi + 3G model)[/i]
This lists 4 technologies for location information.
1. Using the WiFi data to get position (Not as accurate but works
inside)
2. Digital Compass (Provides direction information that GPS can't)
3. Assisted GPS (GPS is GPS, assisted means it combines other data
with the GPS)
4. Cellular (Not very accurate method using GSM towers)
So the iPad does have GPS but only on the 3G model.
There is no such thing as fake GPS - if they say GPS they have to mean
it, it is a defined technology using the Global Positioning System, it is
not some sort of way of saying it can work out where it is.
Anything that does not use the Global Positioning System is not GPS,
A-GPS is also defined as using GPS plus other data. This cannot mean
pretending to have GPS.
This is why Apple correctly lists 4 different technologies. So even if the
A-GPS system cannot find a position, the WiFi based method might
and the Cellular triangulation method might.
As inaccurate as the other methods are, the GPS system is severely
limited also. GPS is accurate if it has a signal, and often it doesn't,
such as indoors or in the back of a car, in which case GPS will just be
unable to give you anything, and you had better hope for Cellular or
WiFi signals.
All models will use data from the Wi-Fi and Compass to work out
where they are.
The 3G model will use data from GPS and from 3 other methods to
work out where they are.
All models will know which way is North - which GPS cannot provide.
Any ambiguity is in the minds of those who wish to pretend that
Apple has failed and do not have the skills to read a technical
document properly.
I think the logic is that if you buy a Wi-Fi only model you want the
cheaper option, and probably intend to use this in one location, so
why pay for a GPS chipset to know the device is where it always is.
If you buy an iPad to take around you probably need the 3G to get on
the net so the GPS is included.
This makes some sense as it saves having 3 ranges. It also makes
sense from a build point of view, the GPS chipset and antenna is
probably on the radio card.
And from a battery life point of view the lack of chipset in the WiFi will
reduce the power consumption.
Also if you buy one of these to use within a building then GPS is
probably not going to work anyway, so why add a radio pack that will
never see a signal?
I do not know the insides of the iPhone but if it is like many GSM
phones there is one board for the CPU etc and one for the Radio pack,
if this is the case then Apple could streamline the product designs and
use the same radio card in the iPad that they use in the iPhone, this
would save a lot of messing around for them and for the consumer in
case of service.
Yet again a whole lot of ignorant people going wild trying to knock down
Apple cause they don't have a clue what they are talking about, and
generally trying to brand Apple users as ignorant cultists, when they are
the ones who need deprogramming and a decent IT education.
get a life guys, sheesh
3G has real GPS, WiFi has none
I think it clearly states the opposite. Under "Location", the Tech Specs page lists "Assisted GPS (Wi-Fi + 3G model)". Now, "(Wi-Fi + 3G model)" could possibly refer to both iPads, but in fact when you look at the headings above it's clear that "Wi-Fi + 3G model" is the name of the iPad that includes both WiFi and 3G. Only this model has any kind of GPS.
Which means the GPS functionality almost certainly is on-chip with the 3G functionality. As with the iPhone, "assisted GPS" means data available over the 3G connection is used to triangulate the user's position in the absence (or prior to the availability) of satellite data. It's GPS-plus, not fake GPS.
Such, at least, is my understanding of the specs.
@adambanksdotcom
RE: Apple iPad: Does it have 'real' GPS?
I have a wifi only ipad, and as far as I can tell it *does* have GPS.
I loaded Navigon, and tried it with WiFi off. No dice.
I then turned on WiFi but made sure it was *not* connected to any network. Navigon now worked just fine. It showed my my actual current location (with 80m accuracy) and was spot on, showing me in the middle of a short block right where I actually was. Hmmn.
So I take a little spin around the neighborhood,making sure to go to the highway where there is no WiFi, and here is what happened. Some GPS, but very very bad GPS.
Here is my completely unscientific theory: WiFi only iPad *does* have the GPS chip, but the chip does *not* work properly without the 3G antennae.
RE: Apple iPad: Does it have 'real' GPS?
RE: Apple iPad: Does it have 'real' GPS?
I think it clearly states the opposite. Under "Location", the Tech Specs page lists "Assisted GPS (Wi-Fi + 3G model)". Now, "(Wi-Fi + 3G model)" could possibly refer to both iPads, but in fact when you look at the headings above it's clear that "Wi-Fi + 3G model" is the name of the iPad that includes both WiFi and 3G. Only this model has any kind of GPS.
Which means the GPS functionality almost certainly is on-chip with the 3G functionality. As with the iPhone, "assisted GPS" means data available over the 3G connection is used to triangulate the user's position in the absence (or prior to the availability) of satellite data. It's GPS-plus, not fake GPS.
Such, at least, is my understanding of the specs.
Ditto
The meaning of assisted GPS
I'm not sure how Apple is using its wording. At my work, and every time I speak with vendors selling us high-precision equipment, assisted GPS is a superset of GPS. This means that you get GPS signals and you correct or enhanced its accuracy based on additional sources.
In automotive the most common one is differential GPS or DGPS, which gets correction signals for atmospheric effects via a radio or a cellular link. You also have WASS and EGNOS providing some differential corrections, although not everywhere. This doesn't help much for multipath though.
Another enhancement in automotive works by integrating sensors like vehicle speed and yaw rate from the ESP (stability control) module.
Another approach is to provide satellite position information via internet or wireless link. This is what for example u-box calls assisted gps
http://www.ublox.com/en/gps-solutions/assisted-gps.html
With this technology, if you manage to get signal for a short time, you can get a fix quickly. So this is good when signals is intermittent, such as in cities or in areas with high trees. You don't need a long time window of nice signal to compute a fix.
If I had to guess, I'd say that Apple is enhancing GPS with either something like u-box A-GPS based on wifi and 3G data, or with their built-in accelerometers to detect movements when GPS signals are not good (low HDOP). The later example is a well-known Kalman filter design problem where you fuse and trade-off between what is more reliable at the particular instant. You can buy off-the shelf systems like that and the technology is very old but constantly improving.
In theory, they could also use wi-fi or cellular information to help identify the location by triangulation. However, this requires cooperation with the cellular carrier and/or hotspot provider, so I doubt they are taking this path.
My take, in order to likelihood are
- something like A-GPS from u-box
- accelerometers from the device
- both of the above
Simulated GPS based on triangulation from towers? No way. You wouldn't get very far with that.
Regards
Correct, a-GPS is just GPS but with faster TTFF...
technology for triangulation to speed up its initial time to first fix. It's
not a "fake" GPS or pseudo GPS.
A-GPS always means GPS, but maybe not standalone
A-GPS ONLY refers to a GPS based system. It does NOT refer to cell id or WiFi, which are non-GPS locating methods. If they are used in addition to GPS, that's called a "hybrid" system, not A-GPS.
In other words, as someone else has mentioned, there has to be a GPS chip involved.
For ATT, the Assistance part usually consists of downloading satellite orbit and status information from the internet, so it can locate itself quicker after being powered off.
The iPad 3G model spec says only A-GPS. So we know it has a GPS chip, and that it can ask for assistance from a server on the network.
What the specs don't say, is if it can also operate in standalone mode without assistance, as can the iPhone and most other smartphones.
Whatever it is...
just like the iphone
Well, except for the phone part.
RE: Apple iPad: Does it have 'real' GPS?
Is it a real GPS
Hmmm...no foolin ...
RE: Apple iPad: Does it have 'real' GPS?
Another question is: Does it matter?
Unfortunately, any device such as a GPS enabled phone isn't going to work for the snowmobile because it relies on an internet connection over the cellular network (or WI-FI) for it's map data. The snowmobile goes in a lot of places where there is no cellular signal but the GPS receiver works great - which is why a device like the Garmin with it's maps stored on the device is the way to go for outdoor sports.
Plus, that 9" screen would kind of get in the way when bolted to the handlebars. And is it water proof like my Garmin?
GPS is used for much more than just navigation