Waas For Automotive Gps Units?

[stevethecache]

What would WAAS add in an Automotive turn-by-turn GPS unit? I turned the setting on and it did not seem to add accuracy or anything

[+EraSeek]

Once you turn it on it must initialize WAAS the first time. This may take awhile and it must be able to 'see' a WAAS satellite to do so. WAAS will add accuracy through corrections, but, keep in mind, sometimes more corrections are needed then at other times. So WAAS will improve accuracy more when there are more errors in th GPS signal. Secondly, the accuracy you gain for what we do is not that earth-shattering. Yes, it helps but you can get along just fine without it.

[Alphawolf]

Well, let's put it this way...If you didn't know WAAS was on, then you would never know it was on...Catch my drift?

Edited June 21, 2006 by Alphawolf

[+Red90]

To answer your question no. Accuracy without WAAS is more than enough for street level guidance.

 

The reason you did not see a change is that it takes a while. 5 to 15 minutes after you have held a WAAS satellite for the corrections to affect the accuracy level.

[+EraSeek]

I think the best way to explain WAAS is to imagine you are in a boat in a very heavy fog and looking for a mooring bouy that has accurate coordinates. Without WAAS it may take several passes before you find your bouy. With WAAS you'll find it the first time.

 

The GPS is not really about location. It is all about timing. That is how you compute location. WAAS is critical for any timing critical task. On cell all towers you will see GPS antennaes. They don't move. They are for timing. I'll bet they use WAAS.

[+apersson850]

There's also the map factor to consider.

When you are using an automotive unit, it's of course implied that you have maps in the unit. Navteq claims that their maps are accurate to within ten meters. Having a position error in the receiver of eight or three meters in such a case doesn't make much of a difference.

Instead, all units I've come across fake the position onto the nearest road, going in the same direction, to avoid making it look like you are driving just beside the road.

Thus they mask both position and map errors with the same operation, effectively nullifying the better accuracy you could obtain from the WAAS/Egnos systems.