Waas gps recivers?

[quickonstep]

whats the deal with them? is it good to have waas turned on or should i leave it off? whats the downlow?

Jesse

[dashrockwell]

Wide Area Augmentation System.
Okay, so what the heck is it? Basically, it's a system of satellites and ground stations that provide GPS signal corrections, giving you even better position accuracy. How much better? Try an average of up to five times better. A WAAS-capable receiver can give you a position accuracy of better than three meters 95 percent of the time.


Enable it!

[quickonstep]

does it have any effect on speed readings? if its more accurate all the way around then ill leave it enabled! but still have yet to see any better accuracy than 14 ft, with a brand new etrex legend

Jesse

[dashrockwell]

I've done this recently because I use GPS all the time with work.

Go outside and mark a waypoint and mark it on the ground. Then turn your gps off and move away from your waypoint and turn it back on again. Hit the "go to" button and see what distance it gives you from your waypoint. Then turn the WAAS off and restart your GPS and hit "go to" again and see what distance it gives you to your waypoint. WAAS enabled usually gives you a much more accurate distance than without it. You probably can't tell a difference with speed.

[Techno]

For it to work it has to be able to lock onto extra sattelites. If it don't then it isn't really on.

[dashrockwell]

WAAS is an updated geometric algorithm, monitoring the GPS constellation to provide improved differential corrections for WAAS enabled GPS receivers.
It's not more Satellites in orbit.

[pyro]

On a Garmin GPS, the primary WAAS satellite will be labeled as #35 or higher. Usually 35 is the one it locks onto that really does the magic.

[Techno]

Partially wrong P- right.

Out of my manual.
when enabled the GPS receiver searches for a WAAS satellite
....
currently the waas system is not fully operational... there are only two satellites in place. The atlantic & the pacific. You must have a clear unobstructed view of the sky for.... to receive the signal.
For more info visit gps.faa.gov.

If its working it will display "WAAS" will be displayed.

With only 2 satellites that leaves dead spots on the earth. 3 are required for complete coverage if geosyncronous. Doesn't say if these are but if parked over an ocean they must be.

[transomstand]

I got a Garmin GPS V for my birthday. It tells me how many satellites it's locked onto, when WAAS is working, and my position accuracy in feet. I've seen accuracy as high as 138 ft and as little as 8 feet. I don't usually pay that much attention, but I'm pretty sure I've seen it lock as many as 6 satellites.
When I was shopping, I wanted to know about speed accuracy, I think the specs from Garmin are the same for both types of units, WAAS capable or not. But check Garmin's web site to be sure.

Pete

[MarkHP]

I don't think WAAS will buy you much for our type of boating. Yes it can improve accuracy, but who cares if it shows you within 50 ft or within 10 ft :) For hand held GPS it also drains the battery much more with WASS enabled. As far as speed accuracy you won't notice a difference.

The company I work for makes GPS systems for aircraft navigation and here it is important but, as Techno points out, it is not fully deployed yet and if you can't 'see' one of the two birds then it don't work.

[dashrockwell]

Only certain satellites pick up the WAAS signal from ground stations depending on where you are.....

"Quote from WAAS Development"
The Wide Area Augmentation System (WAAS) uses a system of ground stations to provide necessary augmentations to the GPS SPS navigation signal. A network of precisely surveyed ground reference stations are strategically positioned across the country including Alaska, Hawaii, and Puerto Rico to collect GPS satellite data. Using this information, a message is developed to correct any signal errors. These correction messages are then broadcast through communication satellites to receivers onboard aircraft using the same frequency as GPS. The WAAS is designed to provide the additional accuracy, availability, and integrity necessary to enable users to rely on GPS for all phases of flight, from en route through GLS approach for all qualified airports within the WAAS coverage area. This will provide a capability for the development of more standardized precision approaches, missed approaches, and departure guidance for approximately 4,100 ends of runways and hundreds heliport/helipads in the NAS. WAAS will also provide the capability for increased accuracy in position reporting, allowing for more uniform and high-quality worldwide Air Traffic Management (ATM). In addition, WAAS will provide benefits beyond aviation to all modes of transportation, including maritime, highways, and railroads.