'Seeing' the EGNOS geostationary sats

[cryptogam]

I've been trying to do some research on how useful a 'waas-enabled' GPS unit would be to me, working mainly in the highlands of Scotland. The Garmin website says that getting WAAS reception may be difficult in hilly areas as a line of sight is needed to (at least one of? all of?) the geostationary satellites. Clearly the same would be true in Europe for EGNOS, which I think uses three geostationary sats.

My question is: does anyone know where these sats are located?

If so it should be possible to calculate where in the sky they will be and therefore from which locations one should be able to receive differential correction - yes?

Thanks in advance to anyone who can furnish me with answers!

Cheers, Joe

[UHF]

In my personal experence in the US, WAAS isn't very useful. I hardly ever see the WAAS icon on my pda saying its being used. When it does come on, my accuracy doesn't change at all. Even with waas, I typically see 12-16 feet accruacy, but never less then 12ft. Without WAAS, I see the same accracy. Personally, WAAS hasnt been of any use at all. However, since they are in GEO orbit, they should never move. The signal should always be realiviely straight up, maybe a few degrees to either side, but close enough to call straight up. Line of site shouldn't matter since its up and not sideways. Once you look at a map where they are located, you shouldn't ever have to calculate where they are since they dont move.

[cryptogam]

Thanks for that UHF. Sounds like your experience isn't uncommon; somone else on this forum reported never getting a diff fix in the 'Garmin GPS with Memory Map' thread.

Coming back to the location of the EGNOS sats - I have been told that, in Northen Britain, it/they are located in the southern sky at an elevation angle of roughly 20 degrees. Thinking about it, a geostationary satellite could never be 'straight up' bacause they must follow an equatorial orbit - so their elavation must always be less than [90 - x] where x is user's latitude. Hadn't figured that when I first posted the question...

I'd be curious to hear from anyone who *does* get differential signal via EGNOS. Are the problems associated with the service being still in test mode, or is it actually just difficult to receive?

Cheers, Joe

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