Re: Portable Gps


Richard Holloway
 

If memory serves, iPhones, at least at one point, were using a database of known wifi reference points to enhance navigation. I also have no doubt cell-based devices can be set to use tower reference points to gain accuracy as mentioned.

The more open the sky view, the more GPS satellites can be tracked by a GPS to gain accuracy, but if a device lacks a cellular connection or wifi with an associated database, options get fewer and fewer, especially for a handheld unit.

One other item of possible interest (thinking of the taxi comment)-- a built in GPS in a car will, at least in some cases, use extra tricks, most notably the antilock brake sensors, to count wheel revolutions and the speedometer when GPS signals gets lost (especially in say, a tunnel) and estimate position based on that. It can be pretty accurate because when you turn the wheels, there is differential between the left and right wheel speeds. (I think that's called the yaw rate.) That trick won't work so well when someone is walking with a handheld. I believe many portable car units will similarly assume continued constant velocity at least for a short time upon signal loss. I have no idea what a Trekker can do in such a situation.

Sent from my iPhone

On Feb 11, 2013, at 9:37 PM, Adrian Spratt <Adrian@...> wrote:

Here in New York city, when I was wanting to buy a GPS device, an
organization conducted a demonstration of the Trekker Breeze. It
misidentified nearby streets and couldn't estimate the distance to
intersections. I was left with a sense that it doesn't pick up the necessary
satellite signal in an environment of tall buildings. I think it's a
question any city resident considering buying a Breeze might look into
first. A friend has used the iPhone (I believe 4S) in Washington D.C. with
more success, so perhaps the app designed for it is a better bet in an urban
environment. This is hardly a good sample size, but the demonstration ended
my interest in the Breeze.

-----Original Message-----
From: Jfw [mailto:jfw-bounces@...] On Behalf Of Jennifer
Tissot
Sent: Monday, February 11, 2013 8:55 PM
To: The Jaws for Windows support list.
Subject: Re: Portable Gps

I haven't heard of Captain Mobility before. will have to look it up.

Trekker Breeze is strictly auditory but can't hook up to a Packmate as
you know. IT does give you which streets are in what direction and
more details if you set a route, and will redirect you if you go
off-route. IT's rather accurate and landmarks are excellent as far a
location goes while passing a particular place.

Unfortunately, it seems that everyone has the standard $700 or so when
it comes to the latest GPS. I had to save a llong time to get mine. Do
you have a Lion's Club where you can inquire about a grant? If you
give a good cause to why you need the device, they most often would be
happy to assist in the funds to get it for you. IT may take some
time--sometimes months before you hear back from them--but I have been
successful in obtaining a few adaptive pieces of tech from them. I
understand about thethe finantial cost. Very high for such rather
essential equipment for most of us.
Jen
On 2/11/13, Karen Hughes <khughes8@...> wrote:
I TOO WAS LOOKING AND TOLD BY MY ADVISOR THE cCAPTAIN WAS A POOR CHOICE.
GOOD LUCK, KAREN

----- Original Message -----
From: "Jamie Davis" <jdmusicman1971@...>
To: <jfw@...>
Sent: Sunday, February 10, 2013 7:53 PM
Subject: Portable Gps






Actually I was looking for a stand-alone gps that is accessible. As an
example, a Garmin. I'm not necessarily lookng for a Garmin, more or less

a
gps where I don't have an extra unit, such as a Braille Note(which I
don't
have), or a PacMate(which I do have). I know Freedom Scientific has the
Street Talk, and I have seen the Trecker Breeze. Not only am I looking
for
a a one unit gps, but something that is more auditory. I read Braille,
but
do more auditorily. I'm loking in to the Captain Mobility gps. Has
anyone
ever heard about that or know anyone who has had one of those? It seems
that no matter what I do, for an accessible gps, I'm going to spend
upwards
of $600. I can't afford that just now. I just started a part-time job
and
it's not even enough to pay the bills. I have other sources which help
in
that manner.



I had a question from a gentlemen when I was enquiring about the usb tv
tuners. The gentlemen said he had the Hauppauge usb tv tuenr. I am
curious
as to what model you have. All of your feedback has been helpful thus
far.
Thanks.



Jamie

Linked IN Profile: <http://www.linkedin.com/in/jamiedavis2>
http://www.linkedin.com/in/jamiedavis2



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