Waas

[Snail Hairs Clan]

Is a WAAS satellite harder for GPS unit to get lock on? I've noticed that I rarely get a differential info indication. Is this more a function of where I am at (Northern California) or that there are less WAAS satellites? I own a Garmin Rino if this makes a difference.

[+Renegade Knight]

My first few go rounds with WAAS I didn't get much results. Then when I first got some WAAS locks (indicated by a D in your satalite bars) my accuracy was reported as lower than with out WAAS.

 

Finally I turned on WAAS and forgot about it. Then I notied my EPE which normally is 15-20' was 7' and I looked and saw WAAS working. It seems to take some time for the GPS to sort it all out.

[+Criminal]

Another answer is, yes.

 

The WAAS birds must be geosynchronous, so they are over the equator. That puts them very low on the horizon for you and me. With an amplified antenna on my truck i lock on pretty quick, and see the 7' accuracy most of the time.

[+wxboss]

I believe you're right. I want to say that they are around the Tropic of Cancer and located near the East & West coastlines. I usually don't have too much of a problem getting good differential information on my GPS here in Florida.

[Kerry.]

Now that WAAS has been found not able to meet Category 1 performance at most US airports funding has been cut due to the now reduced expectations regarding WAAS performance.

 

Based on the funding cutbacks maybe the future of WAAS might be a little suss?

 

Cheers, Kerry.

[+GOT GPS?]

http://www.aopa.org/pilot/features/future0005.html

 

Well, there’s some good news and some bad news about WAAS.

 

The good news is that the accuracy being achieved with WAAS is almost four times better than expected. The aviation industry reaffirmed the need for WAAS at a March 15 summit called by AOPA and the Air Transport Association (ATA), which represents major airlines. The summit called for the FAA to fix the problems it has encountered with WAAS and to deploy an operational system as soon as possible.

 

The bad news is that achieving, or at least proving, the necessary integrity—the ability to provide timely warning of erroneous information that should not be used for navigation—has been more difficult than anticipated. As a result, the initial implementation of WAAS will be delayed at least a year. When it becomes available, WAAS will provide lateral and vertical navigation (LNAV/VNAV) approach capability to minimums of 350 feet and 1 mile. This won’t be quite as low as the previously promised 200 and one-half—but the approaches won’t require expensive approach lighting systems and other airport improvements needed for a Category I ILS, either. Lower minimums are expected in the future, but more development work and possibly operational experience will be required first.

Edited May 14, 2004 by GOT GPS?

[DavidSweet]

Pretending you live in Yreka, California, There are two WASS satellites that you might lock onto:

 

POR which is situated at 178º East and

AOR-W at 54º West

 

At Yreka, POR has a bearing of 249º (232º magnetic) at an elevation(angle above level) of 7º.

AOR-W has a bearing of 105º (88º magnetic) at an elevation of 14º.

 

Magnetic Declination 16.87º

 

So yes, both are close to the horizon there, but AOR-W is not terribly close. Try finding a spot with a clear view of your magnetic east and try WAAS there. If you have a Garmin, that would be satellite number 35. POR is #47. Magellan does not show the satellite number(AFAIK). I have a protractor-ruler to verify I have a sufficiently low horizon.

 

Info at GPSInformation: WASS

 

Good Luck