Verizon Wireless thumbs its nose at the iPhone

On 2007-07-08, Mitch <mitch@hawaii.rr> wrote:
> Kurt Ullman <kurtullman@yahoo.com> wrote:
>> > > Though you're more likely to get an answer from the makers
>> > > of the Neo1973 -http://wiki.openmoko.org/wiki/Neo1973
>> > > or from http://howstuffworks.com
>> >
>> > How Stuff Works gave a good start, then gave up when it got to my part
>> > of the question -- does it really use GPS satellites and calculations
>> > to build the location?
>>
>> Most, although from my reading on google, seems as though some
>> companies might be using a triangulation method from the cell towers.
>
> Here's the reason for my question:
> if these phones actually use GPS, and are therefore full GPS units, why
> is anyone trying to sell GPS units?

I think the answer you might be missing is that, while the CDMA phones
that Sprint and Verizon sell actually use GPS, it doesn't follow from
this that the phones by themselves are actually "full GPS units".

A "full" GPS navigation receiver needs to perform three functions:

(1) Satellite acquisition, where the receiver discovers which satellites
it can hear and approximately where the signals are located in time;

(2) Make precision time-of-arrival measurements on the signals from the
available satellites; and

(3) Use the timing information from (2) plus knowledge of the locations
of the satellites in space to compute a navigation solution.

With CDMA phones, only (2) is done by the phone. (1) and (3) are done
by the network. That is, the tower tracks which satellites are available
and tells the phone where to listen for them. The phone makes the
precision timing measurements on the signals it can hear and returns
the results to the network. A processor in the network computes the
location of the phone from this timing data. Note that the phone
actually measures time-of-arrival not only of GPS signals but also
CDMA tower signals, and sends the latter back too, so the navigation
solution the network comes up with is actually a best estimate using
both GPS and tower triangulation data.

So, while the phones actually use GPS, the phones by themselves are
not full GPS units and omit all the computing resources needed for
satellite acquisition and the navigation computation. While the
phone makes the GPS measurements the phone itself doesn't know where
it is located (unless the network tells it). If the phone loses its
connection to the CDMA network it loses the GPS capability entirely.

> Why aren't the cell makers building all GPS features into their
> already-capable phones? (Note that giving directions is not a GPS
> feature, but an application of GPS info.)
> Why are all GPS devices larger (some by several times) than all cell
> phones, when small size is just as useful to those?
> Why aren't better GPS features appearing in cell phones?

See above. The phone itself doesn't include a full GPS receiver, the
most complex functions of a GPS receiver are done for the phone by
the network. The phone itself doesn't know where it is, and the
network likely doesn't track the phone's location continuously either.
The network only bothers to ask the phone to make measurements when
the network wants the data, say for E911 purposes or to provide a
location-based service which someone is paying the network for.

> I think the reason is that they don't have GPS at all, but a simpler
> triangulation off cell antennas. That may be enough for E911, maybe
> even for giving directions, but it doesn't give them the right to call
> it GPS or take advantage of the popular assumption of GPS accuracy.
> It's not a satellite system and it's not global and it doesn't deserve
> the acronym or the reputation.

No, CDMA phones really do use GPS, and really will get GPS accuracy
when the phone is hearing the GPS satellites well (the latter is, however,
a problem for the phones since their GPS antennas are likely less good
than real GPS units, and the phones are less likely to be used where
they have a clear view of the sky). The problem is your assumption
that, because the phones use GPS, they must include a full GPS
receiver and be able to autonomously support all the functions that
real GPS receivers do. That's not true, most of the GPS functionality
is provided by the network.

Dennis Ferguson

Mitch <mitch@hawaii.rr> wrote
> Rod Speed <rod.speed.aaa@gmail.com> wrote

>>> Here's the reason for my question:
>>> if these phones actually use GPS, and are therefore
>>> full GPS units, why is anyone trying to sell GPS units?

>> For the same reason that we see cellphones with built in media
>> players and cameras and separate media players and cameras too.

> Reasonable. But why wouldn't more cell makers try to build on that?

Essentially because the cellphone market is dominated by very cheap
phones and full mapping on cellphones requires quite a bit of decent
hardware for the mapping function, storing the maps and doing the
routing etc, quite apart from what provides the GPS location data.

The Nokia N95 which has real GPS, not triangulation,
and full mapping, isnt a cheap cellphone.

>>> Why aren't the cell makers building all GPS
>>> features into their already-capable phones?

>> Because app accessible GPS isnt the same as what satisfys the
>> legal requirement for location good enough for the 911 service etc.

> That's strange, because I don't know how much
> you can lose of GPS ability and still get a location.

Cant understand that sentence, try again.

>>> (Note that giving directions is not a GPS
>>> feature, but an application of GPS info.)
>>> Why are all GPS devices larger (some by several times)
>>> than all cell phones, when small size is just as useful to those?

>> Mainly because mapping needs a better
>> screen than the smallest cellphone screens.

> You'd think so, conidering how much info a map has to offer.
> But some GPS are very low-res, even with map viewing.

Sure, and those are quite viable if you just want turn indications etc.

Some of us want a decent resolution display like you get with google maps tho.

The cheapest satnavs are a lot more expensive than the cheapest cellphones for a reason.

>> There are satnavs that are otherwise as small as cellphones.

> Yeah, probably. The ones I know aren't the most expensive,
> and the smaller of the ones I know are arm-band units.

>>> Why aren't better GPS features appearing in cell phones?

>> They are, most obviously with the Nokia N95 which has full routing just like a satnav.

> That's neat.

>>> I think the reason is that they don't have GPS
>>> at all, but a simpler triangulation off cell antennas.

>> You're just plain wrong. If that was true, they wouldnt
>> be able to show the number of GPS satellites currently
>> in view, and they can and do show that.

> But I'm still talking of the ones that don't,
> which seems to be almost every cell phone.

Sure, some choose not to use real GPS. Thats nothing
like your original claim that none of them do tho.

>>> That may be enough for E911, maybe even for giving directions,
>>> but it doesn't give them the right to call it GPS or take advantage
>>> of the popular assumption of GPS accuracy.

>> They have real GPS anyway.

> Right; my statement is about if they do NOT.

You claimed that none of them have real GPS, thats just plain wrong.

>>> It's not a satellite system and it's not global and
>>> it doesn't deserve the acronym or the reputation.

>> Pity about the cellphones which have real app accessible
>> GPS and show the number of GPS satellites currently in view.

> Again, my statement was (very clearly, I thought) about
> the units which do not. Isn't that nearly all of them?

You claimed that none of them have real GPS. Thats just plain wrong.

Mitch <mitch@hawaii.rr> wrote:
> In article <5fbq64F3bc7e2U1@mid.individual.net>, Rod Speed
> <rod.speed.aaa@gmail.com> wrote:
>
>>> What I'm wondering is if people are being told it is GPS they are
>>> getting when the system merely uses cell towers to set the location?
>>
>> Nope, its real GPS with the Nokia N95.
> That would figure; it should certainly be more visible and better
> presented on a smart phone.
>
>>>> Though you're more likely to get an answer from the makers
>>>> of the Neo1973 -http://wiki.openmoko.org/wiki/Neo1973
>>>> or from http://howstuffworks.com
>>
>>> How Stuff Works gave a good start, then gave up when it
>>> got to my part of the question -- does it really use GPS
>>> satellites and calculations to build the location?
>>
>> Yep. It even shows the number of satellites it can see, just like a
>> satnav does too.

> Very nice. I hope they put in some of the other GPS features,
> but I've never heard of one that invites map data.

The Nokia N95 does, full routing too.

And you can use google maps as well if you want to.

The reason that cheap cellphones dont is because full maps in the
phone requires hardware the cellphone doesnt have for the maps alone.