[OSM-talk] Quality of Sirf star 3 tracks disappointing...

Tue Jul 11 09:45:13 BST 2006

Yes, if you are seeing D's on the satellite bars when WAAS is enabled you
are picking up the EGNOS (or WAAS) transmissions and the data for the
satellite with the D is receiving corrections. On Garmin units. Sat 33, 37
and 39 currently make up the EGNOS platform and normally two channels of the
GPS receiver are reserved for two of these when SBAS (Satellite Based
Augmentation System, ie WAAS or EGNOS) is enabled. WAAS and EGNOS do the
same thing. Just that WAAS is for the Americas and EGNOS for Europe and
Africa. The Japanese system is not up and running yet.

The EGNOS platform is just this month moving from test mode to initial
operations mode when the correction data should be available all the time. 

For more about SBAS check out this useful site:

http://www.kowoma.de/en/gps/waas_egnos.htm

Cheers,

Andy

Andy Robinson
Andy_J_Robinson at blueyonder.co.uk 

>-----Original Message-----
>From: talk-bounces at openstreetmap.org [mailto:talk-
>bounces at openstreetmap.org] On Behalf Of Nick Black
>Sent: 11 July 2006 09:31
>To: Barnett, Phillip
>Cc: talk at openstreetmap.org
>Subject: Re: [OSM-talk] Quality of Sirf star 3 tracks disappointing...
>
>On 7/10/06, Barnett, Phillip <Phillip.Barnett at itn.co.uk> wrote:
>>
>>
>>
>> Yep, D's in the bars mean you're picking up WAAS/EGNOS signals from those
>> satellites.
>> Phillip
>
>I dont know exactly what the "D" means, but I dont think they mean
>that the receiver is picking up EGNOS signals from NAVSTAR (GPS).
>There are three satellites that currently make up the EGNOS system, in
>geostaionary orbit so that they can broadcast over Europe.  The three
>satallites really do very little (compared to a NAVSTAR, GLONASS or
>GALILEO) satellite.  'All' they do is receive a broadcast signal from
>European (ESA controlled) monitoring stations, and relay the signal
>back to Earth, where it can be reiceived and understood by compatible
>GPS receivers.
>
>The signal contains precise inforamtion about the orbit (ephemeris) of
>GPS and GLONASS satellites, about ionospheric interference and about
>the accuracy of the atomic clocks onboard the Navstar satellites. In
>this way the system differs from Differential GPS and from A-GPS.
>D-GPS works by 'averaging out' errors by placing a super accurate
>receiver over a known position and relaying the differentials to a
>less accurate reciever.  EGNOS is a lot more intelligent than that as
>it deals with live data relating to various conditions.
>
>I am still uncertain whether I have ever picked up an EGNOS signal.  I
>have a Garmin GPS 60 which, according to ESA
>(http://esamultimedia.esa.int/docs/egnos/estb/SBAS_receivers.pdf)
>isn't supported.  The manual however says the unit does support EGNOS
>and WAAS.  I also noticed the "D"s the other day, when I was on a
>south facing hill, so I dont think that its a coincidence.  I think
>its more likely that the Ds mean that the reciever has picked up the
>correction information for that satellite.  Anyone got anymore ideas?
>
>Nick
>
>
>
>
>>
>>
>>
>> -----Original Message-----
>> From: talk-bounces at openstreetmap.org on behalf of Jon Stockill
>> Sent: Mon 7/10/2006 11:15 PM
>> To: talk at openstreetmap.org
>> Subject: Re: [OSM-talk] Quality of Sirf star 3 tracks disappointing...
>>
>> Lars Aronsson wrote:
>>
>> > With time and experience, I've come to use the satellite view
>> > (showing signal strengths) on my Garmin while I'm moving around.
>> > It's no point in running around if no signal is received.
>>
>> I was doing that at the weekend when I noticed little D's appear on all
>> the signal strength bars on my GPS60 - this isn't mentioned in the
>> manual, but I guess it means WAAS was working - because the error
>> estimate shown at the top of the page dropped to 2m - definitely the
>> most accurate coverage I've ever seen. Definitely a good upgrade from my
>> old GPS12 - the screen is MUCH nicer, the battery life longer (on half
>> the number of cells) and it'll store 10,000 trackpoints rather than
>> 1024. Not only that, but I find it incredibly useful to save the tracks
>> (after downloading of course) as it then gives you a reference on the
>> map view for where you've already been.
>>
>> Jon
>>
>> _______________________________________________
>> talk mailing list
>> talk at openstreetmap.org
>> http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
>>
>>
>>
>> Phillip
>>
>>
>>
>> -----Original Message-----
>> From: talk-bounces at openstreetmap.org on behalf of Jon Stockill
>> Sent: Mon 7/10/2006 11:15 PM
>> To: talk at openstreetmap.org
>> Subject: Re: [OSM-talk] Quality of Sirf star 3 tracks disappointing...
>>
>> Lars Aronsson wrote:
>>
>> > With time and experience, I've come to use the satellite view
>> > (showing signal strengths) on my Garmin while I'm moving around.
>> > It's no point in running around if no signal is received.
>>
>> I was doing that at the weekend when I noticed little D's appear on all
>> the signal strength bars on my GPS60 - this isn't mentioned in the
>> manual, but I guess it means WAAS was working - because the error
>> estimate shown at the top of the page dropped to 2m - definitely the
>> most accurate coverage I've ever seen. Definitely a good upgrade from my
>> old GPS12 - the screen is MUCH nicer, the battery life longer (on half
>> the number of cells) and it'll store 10,000 trackpoints rather than
>> 1024. Not only that, but I find it incredibly useful to save the tracks
>> (after downloading of course) as it then gives you a reference on the
>> map view for where you've already been.
>>
>> Jon
>>
>> _______________________________________________
>> talk mailing list
>> talk at openstreetmap.org
>> http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
>>
>>
>>
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