EGNOS - is it up and running

[philip_stevens]

and if so, how have you found it for reliability and accuracy??

I was in Looe a couple of weeks ago, and switched EGNOS on to see if it made any difference to our position - alongside the visitors berth. It did - it put us out in the middle of the harbour!!

If I had had it on, and was hoping to find Looe entrance in fog, it would have put us on the beach (just supposing I wasn't watching my sounder and radar).

As soon as I disabled EGNOS, we went back alongside the quay - exactly where the normal GPS satellites put us in the first place. Also, due to the high sided valley, not all satellites were visible to the GPS, but the EGNOS was.

After that trial, I don't think I will be using it until someone tells me it is definitely reliable.

 

[rickp]

Without knowing more about what you actually picked up as "EGNOS", its hard to say. The satellite broadcasting the EGNOS corrections do so with them marked as "unusable". I can tell my Simrad GPS to ignore the "unusable" flag and use the corrections anyway, but by default it won't.

Perhaps you were picking up WAAS corrections - which will be completely wrong for Europe as they are correcting for atmospheric conditions over the US.

Rick

 

[VicS]

It might be worth trying the gps navigator Yahoo group http://groups.yahoo.com/group/gps-navigator

Also HERE

 

[philip_stevens]

I don't think there is any way on my plotter to differentiate between WAAS and EGNOS. It's just a switch to enable "differential", and all I get on the plotter is WS when it is picking up the differential. It looks as though it is over Europe, as the position is very high azimuth, and in a generally SE direction. If it was WAAS I would think it would show up as lower azimuth and well over to SW direction.

Would WS indicate WAAS? If so, what would EGNOS show up as?

I will post this on GPS-Navigator as well.

 

[rickp]

Differential GPS is a much overloaded term. EGNOS/WAAS is often referred to as "Wide Area DGPS" or sometimes SDGPS (Satellite Differential GPS). My GPS claims not to support DGPS, but happily supports SDGPS. My RC-400 does support DGPS but is always complaining about losing the "differential fix" *shrug*.

I've just fired up my GPS and I can see that AOR-E (Satellite 120) is still broadcasting a type-0 warning which is the "don't use for navigation" flag. I can't get a lock on the other satellites currently to check (those being ARTEMIS (124), INMARSAT (126) and IOR (131)) but I'd be really suprised if they were broadcasting without that flag as the last I read implied that EGNOS was not going to be certified until 2008.

Rick

 

[BrendanS]

You can see real time perfomance here, though I rarely check these days

http://www.egnos-pro.esa.int/IMAGEtech/imagetech_realtime_html.html

 

[rickp]

Yes, from what I've seen the performance should be pretty good. We just need them to extract digit and set it live by broadcasting type-2 messages rather than type-0.

Rick

 

[philip_stevens]

There is no warning on our plotter - Navman 5500 - and it shows WS as being "used". There is no other info on the sats.

On our old AP-Philips Mk6, I can see which sat is healthy or unhealthy, but that GPS only uses land based differential, whereas the Navman manual states that it will only pick up sat diff.

When I had the AP on a previous boat, it was fed info from a dGPS receiver, but that was in the days before Clinton had SA switched off. I must admit that in those days, it was extremely accurate - being only 10 or so miles from the diff tx at the Lizard.

As I said earlier, I won't be using sat diff until I am assured it is working properly.