Waas

[sh33p]

Anyone manage to get WAAS to work here in Victoria, BC, or we just too far north still?

[+Prime Suspect]

WAAS is for the US only. Even if you get a signal, it won't mean anything, since the correction data won't apply to where you are.

Edited October 15, 2004 by Prime Suspect

[+EraSeek]

WAAS is for the US only. Even if you get a signal, it won't mean anything, since the correction data won't apply to where you are.

Not exactly true. It does extend into parts of Canada, and certainly is useful in Victoria, especially as Victoria is projected into the Washinton lat/long area.

View current service area in this link: http://www.nstb.tc.faa.gov/vpl.html

[+PDOP's]

You should have no problems getting WAAS signals in Victoria as long as you have a clear view of the sky to the south. There's a ground reference station in Seattle so the corrections will be accurate. For more on this have a look at My Webpage and at this webpage.

 

There's an article here which has the details of WAAS expansion into Canada.

[+FarSideX]

There is more then 1 level of WAAS. NPA and PA. NPA is accurate to 7 meters compaired to 15 meter non-waas. PA is 3 meter accurate.

There is 99.9% coverage of NPA WAAS in Canada, this is the same as the USA. (Percentage is for time available to that location). There is some PA coverage in some parts of Canada (usually close to the US boarder).

Using WAAS in Canada is generaly not as accurate as in the USA but is more accurate then not using it.

[+EraSeek]

There is more then 1 level of WAAS. NPA and PA. NPA is accurate to 7 meters compaired to 15 meter non-waas. PA is 3 meter accurate.

There is 99.9% coverage of NPA WAAS in Canada, this is the same as the USA. (Percentage is for time available to that location). There is some PA coverage in some parts of Canada (usually close to the US boarder).

Using WAAS in Canada is generaly not as accurate as in the USA but is more accurate then not using it.

Please clue me in as to what "NPA" and "PA" stands for.

[gpsdork]

Last year, we made repeated attempts to acquire a WAAS signal while at Mt. Logan in the Yukon (northern Canada). I think the corrections would have been useful, since we were about midway between the the two WAAS ground stations at Anchorage and Yukatat on the panhandle.

 

Anyway, we had an uninterrupted view of the southern horizon, but had no luck locking onto POR or AOR (and I've forgotten all my spherical trig, so couldn't calculate whether the the sats were above our horizon).

 

But I wodnered why the WAAS signal couldn't be transmitted from *ll*the GPS sats (along with the "conventional" GPS signal)? Why must they be transmitted from a geostationary sat

[+blindleader]

But I wodnered why the WAAS signal couldn't be transmitted from *ll*the GPS sats (along with the "conventional" GPS signal)? Why must they be transmitted from a geostationary sat

It probably could have been. But WAAS is a creature of the FAA, which undoubtedly has zero influence with the military entity responsible for Navstar. To get two very large bureaucracies like this, with divergent agendas, to cooperate on a large technical project would probably have been a laughable concept to the entities involved. It was hard enough to get the various armed forces (with presumably the same agenda) to get their electronic systems to talk to each other after the first Gulf War.

[Blue Contrails]

When I took my GPSr up to Canada I couldn't get any WAAS. So it WAASn't.

[+FarSideX]

Please clue me in as to what "NPA" and "PA" stands for.

Non Precision Approach and Precision Approach, the terms are usually used when discussing vertical accuracy of the WAAS system. Sometimes considered to mean Non Precision Accuracy and Precision Accuracy.

[+apersson850]

Technically, any SBAS system could work from satellites in orbits like the ordinary GPS sats. The MSAS system, planned to give the same kind of service to Japan, is planned to work like that. But since these sats then go out of sight twice a day, there has to be more of them to provide continious service.

With the geostationary approach, used by WAAS, only two sats are enough to cover North America. Provided you can receive them. But from an aircraft, which is what they were intended for from the beginning, that's not a problem.

[+Ex nihil]

I am not sure that WAAS is all that useful, in or out of the USA. For Australians who might be checking out this thread look at the interesting explanation at http://www.gpsoz.com.au/WAAS.htm

[+kingquad]

I know for myself in Ontario Canada with an etrex legend the only big difference i see with WAAS turned on is the battery consumptions that sky rockets beside that i dont see a big diference in accuracy. so it is always off on my unit.