[gps-talkusers] Selective Availability and DGPS
- From: Kevin Chao <kevinchao89@xxxxxxxxx>
- To: <gps-talkusers@xxxxxxxxxxxxx>
- Date: Fri, 25 Apr 2008 12:11:35 -0700
Scott,
The 100 meters of inaccuracy that you are refering to is no longer in effect
as of May 1, 2000. This is a feature known as Selective Availability (SA)
and is included in all GPS, which is currently disabled. This was something
that teh military enabled that scrambled the signals making the publically
acessible signals very inaccurate.
Today, without corrected signals, the horizontal accuracy can be 10 meters
on average and the vertical accuracy can be 30 meters on average.
If one is taking advantage of the Differential GPS signals (DGPS), then the
horizontal accuracy can be as as good as 3 meters. DGPS is known as the WAAS
reading in Northern America and EGNOS in Europe and other locations. I
beleive that the EGNOS is something that is still in the works.
I apologize for the long and technical response but wanted to clear up any
possible confusion.
Kevin
-----Original Message-----
From: gps-talkusers-bounce@xxxxxxxxxxxxx
[mailto:gps-talkusers-bounce@xxxxxxxxxxxxx] On Behalf Of Scott Granados
Sent: Friday, April 25, 2008 11:16 AM
To: gps-talkusers@xxxxxxxxxxxxx
Subject: [gps-talkusers] Re: The M1000 & wayfinder access
You know, if you're not getting a corrected signal you could be off as much
as 100 meters.
----- Original Message -----
From: "Kim Lookingbill" <seadolphink@xxxxxxxxxxx>
To: <gps-talkusers@xxxxxxxxxxxxx>
Sent: Friday, April 25, 2008 11:16 AM
Subject: [gps-talkusers] Re: The M1000 & wayfinder access
> Hi: - I guess then it must be bad mapping since this is the suburbs and
> not
> downtown with real tall buildings to bounce off, although there's lots of
> buildings. Also the roads it reports do not even intersect with the road
> I'm on, though as I stated previously the two roads do run parallell to
> each
> other but a block or two apart. I'm gonna do some more testing by taking
> my
> n1000 with my braille note and see if I get the same results or not. I'll
> let you know when I do, though this won't be until Monday or Tuesday when
> I
> can do so. Thanks for the response..
>
> Kim Lookingbill
> kim@xxxxxxxxxxxx (email or MSN Messenger)
>
> Blast From The Past
> Sundays, 16 to 19 UTC
>
> http://interactive.acbradio.org
>
>
> -----Original Message-----
> From: gps-talkusers-bounce@xxxxxxxxxxxxx
> [mailto:gps-talkusers-bounce@xxxxxxxxxxxxx] On Behalf Of Kevin Chao
> Sent: Thursday, April 24, 2008 8:42 PM
> To: gps-talkusers@xxxxxxxxxxxxx
> Subject: [gps-talkusers] Re: The M1000 & wayfinder access
>
>
> Kim,
>
> Is this issue of WayFinder Access reporting you as being several blocks
> from where you are specific to this area or is it something that happens
> to
> a greater extent? This could be an issue of poor map data or GPS drift,
> which is caused from signals bouncing off of tall or very tall
> buildings.
> If it is something specific to this area and there are tall buildings then
> it could be an issue of GPS drift. But if it is something that is specific
> to this area and there aren't tall buildings then the issue could be poor
> mapping data. I have never experienced the Sendero GPS reporting me to be
> no
> more than 2 blocks at most off and that is in situations where multi-path
> and drift are at its worst in San Francisco with sky scrapers.
>
> Please provide us with more information about the situation so we can
> narrow down on what is happening.
>
> Kevin
>
> -----Original Message-----
> From: gps-talkusers-bounce@xxxxxxxxxxxxx
> [mailto:gps-talkusers-bounce@xxxxxxxxxxxxx] On Behalf Of Kim Lookingbill
> Sent: Thursday, April 24, 2008 4:18 PM
> To: gps-talkusers@xxxxxxxxxxxxx
> Subject: [gps-talkusers] Re: The M1000 & wayfinder access
>
> Hi: - When using the N1000 with wayfinder access is there any way to
> adjust
> the reciever's viewing distance. I'm finding that the reciever is
> reaching
> to far out and is reporting streets several streets over instead of the
> actual streets being driven past. For example: here in the DC metro area
> if
> I'm travelling down Rt. #270 (running parallell to Rt. #270 is Rt. #355,
> however, the street itself is several blocks over), so I'm on Rt. #270,
> the
> N1000 reads pois and cross street on Rt. #355, instead of what I'm
> actually
> passing on Rt. #270. Oh yes, and just a little trivia for everyone, Rt.
> #355 is a road that travels through Montgomery County from the district to
> the frederick county line; going north to south, and although it's the
> same
> road, it name changes four (4) times depending on the portion of road you
> are on. The four different names starting at the district line are: (1.)
> wisconsin avenue, (2.) rockville pike, (3.) hungerford drive, (4.)
> frederick
> road. So if there are any hints, tips, or tricks to narrow its scope of
> view, that would be smashing. Thanks.
>
> Kim Lookingbill
> kim@xxxxxxxxxxxx (email or MSN Messenger)
>
> Blast From The Past
> Sundays, 16 to 19 UTC
>
> http://interactive.acbradio.org
>
>
> -----Original Message-----
> From: gps-talkusers-bounce@xxxxxxxxxxxxx
> [mailto:gps-talkusers-bounce@xxxxxxxxxxxxx] On Behalf Of Michael May
> Sent: Thursday, April 24, 2008 2:09 PM
> To: gps-talkusers@xxxxxxxxxxxxx; gps-talkusers@xxxxxxxxxxxxx
> Subject: [gps-talkusers] Re: The M1000
>
>
> The receiver would perform the same no matter which PDA you used it with.
> It
> is pretty darn sensitive.
>
> I would remind users that the number of satellites isn't the final word on
> the accuracy. If you are getting satellites inside or in an urban canyon
> situation, the number of satellites might be high but the quality of
> signal
> will be degraded. Always doublecheck the information if accuracy matters.
>
> Mike
>
> At 05:52 AM 4/24/2008, Wendy Slominsky wrote:
>>Are you using this with PK or the like?
>>At 06:31 AM 4/24/2008, you wrote:
>>>I thought I'd never be able to use the GPS in our new train carriages
>>>(nothing else does), but so long as I have it turned on before I get
>>>on the train the M1000 works perfectly. Best investment I ever made.
>>>
>>>Judi
>>>
>>>
>>>
>>>----------
>>>From: meearls@xxxxxxx
>>>To: gps-talkusers@xxxxxxxxxxxxx
>>>Subject: [gps-talkusers] Receiver Question:
>>>Date: Wed, 23 Apr 2008 19:06:32 -0700
>>>
>>>Usually when I use a receiver in the car, I leave it on the strap,
>>>however yesterday, I was using a Voice Sense with Sense Nav and did
>>>have the receiver up against the car window. It was super neat because
>>>Sense Nav overwrote the route that had been automatically programmed
>>>into it before I went to the cell phone store.
>>>With the Holux m1000, I have had a reading of 8 satellites clear
>>>across the living room from the patio door.
>>>Mary Ellen Earls
>>>
>>>
>>>
>>>----------
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>
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>>
>
>
> Michael G. May
>
> CEO Sendero Group
>
> "The GPS company:" Sendero Featuring GPS on the mPower, PK and Voice
> Sense.
> Also distributing Trekker, Victor Stream, KNFB Mobile Reader, Talks,,
> Tiger
> embossers, Miniguide and ID Mate
>
> Crashing Through by Robert Kurson available at
> http://www.CrashingThrough.com
>
> MikeMay@xxxxxxxxxxxxxxxx
> http://www.SenderoGroup.com
>
> 1-888-757-6810, Fax (530) 757-6830, Mobile (530) 304-0007 Sendero Group,
> LLC
> 1118 Maple Lane, Davis, CA 95616-1723, USA
>
>
>
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