Garmin GPS - Nuvi WAAS

Author

Nuvi WAAS

Bruce.

2007-07-29, 3:33 pm

Here's a reply I got over at GpsPasSion forum asking about WAAS. I'm
currently experimenting with pointing my 650 at the southern sky to see if I
can get a 35 or 47 lock. I'm fairly north in Chicago so I may not be able
to pick it up.

Bruce.

Here is Garmin's answer. And the D(ifferential) indicator is all there is to
indicate successful reception.
-----------------------------------------------------------

Depending on your location, you may not have a good line of sight to the
required WAAS satellite which will make signal reception very difficult.
You may not have collected enough information from the WAAS satellite. (See
below for details.)

Detail:
There are currently two WAAS satellites that can be received in the United
States. One is over the Atlantic Ocean and one is over the Pacific Ocean.
The satellites are in a geo-stationary orbit over the equator, so the
farther north you are, the greater the difficulty in picking up the signal.
These factors put the satellites very close to the visible horizon, allowing
the signal to be blocked by terrain or buildings (the WAAS signal is in the
same frequency range as the GPS signal and is a line of sight transmission).
The best results using WAAS with gps units will occur by literally
"pointing" the patch antenna of the unit at the location of the satellite.
You can determine this by looking for satellites 35 (East Coast) and 47(West
Coast) on the Satellite Status page in your GPS unit.
You will need to allow the unit to have good visibility of the WAAS
satellites and track the signal for 10-20 minutes. After the initial data
collection takes place, the unit will be able to quickly acquire the WAAS
satellites and will normally take about 1-2 minutes to obtain a differential
position fix. For more information on how to read the satellite status page,
please refer to the appropriate owner's manual for your GPS.

skmort@lanset.com

2007-07-29, 10:33 pm

On Jul 29, 12:41 pm, "Bruce." <no...@nowhere.com> wrote:
> Here's a reply I got over at GpsPasSion forum asking about WAAS. I'm
> currently experimenting with pointing my 650 at the southern sky to see if I
> can get a 35 or 47 lock. I'm fairly north in Chicago so I may not be able
> to pick it up.
>
> Bruce.
>
> Here is Garmin's answer. And the D(ifferential) indicator is all there is to
> indicate successful reception.
> -----------------------------------------------------------
>
> Depending on your location, you may not have a good line of sight to the
> required WAAS satellite which will make signal reception very difficult.
> You may not have collected enough information from the WAAS satellite. (See
> below for details.)
>
> Detail:
> There are currently two WAAS satellites that can be received in the United
> States. One is over the Atlantic Ocean and one is over the Pacific Ocean.
> The satellites are in a geo-stationary orbit over the equator, so the
> farther north you are, the greater the difficulty in picking up the signal.
> These factors put the satellites very close to the visible horizon, allowing
> the signal to be blocked by terrain or buildings (the WAAS signal is in the
> same frequency range as the GPS signal and is a line of sight transmission).
> The best results using WAAS with gps units will occur by literally
> "pointing" the patch antenna of the unit at the location of the satellite.
> You can determine this by looking for satellites 35 (East Coast) and 47(West
> Coast) on the Satellite Status page in your GPS unit.
> You will need to allow the unit to have good visibility of the WAAS
> satellites and track the signal for 10-20 minutes. After the initial data
> collection takes place, the unit will be able to quickly acquire the WAAS
> satellites and will normally take about 1-2 minutes to obtain a differential
> position fix. For more information on how to read the satellite status page,
> please refer to the appropriate owner's manual for your GPS.

Unfortunately WAAS satellite ID 35 was moved from W 54 to W 142 last
spring!!

The good news is that there are 2 new WAAS satellites!! ID 48 at W
133,, still undergoing testing, but sometimes sending data,, and
ID 51 at W 107.5 which was to go into full operation around the middle
of July! I do know that I was getting a good strong signal with
correction data the first part of June when visiting Cedar Point in
north Ohio!!

Here is a link (PDF) to status, which is only updated from time to
time!

http://www.nstb.tc.faa.gov/incoming..._Geo_Status.pdf

While checking the link, I notice that it is a FINAL report because
they, (both Satellites) are now operational, with future software
upgrades planned to one of them!!!
SKM

skmort@lanset.com

2007-07-29, 10:33 pm

Bruce.

2007-07-30, 10:33 am

<skmort@lanset.com> wrote in message
news:1185762405.582400.77600@j4g2000prf.googlegroups.com...
> The good news is that there are 2 new WAAS satellites!! ID 48 at W
> 133,, still undergoing testing, but sometimes sending data,, and
> ID 51 at W 107.5 which was to go into full operation around the middle
> of July!

Ah, that explains why I was seeing 48 and 51. Thanks for the information.

> I do know that I was getting a good strong signal with
> correction data the first part of June when visiting Cedar Point in
> north Ohio!!

Have you noticed any difference in accuracy when you're receiving a WAAS
satellite?

Bruce.

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