How to fix faulty GR-230 units

DinAlt · Posted: Fri Jan 09, 2004 3:35 pm Post subject: How to fix faulty GR-230 units

Hi all,

I visited Holux-UK's office today and they very kindly reset my GR-230 for me (procedure took less time than a soft reset of my IPAQ).

They asked me to pass on the following message :

They are very happy to reset anyone's receiver for them - they'll do this free of charge as long as you cover the postage costs (the suggestion was to put a pre paid self addressed jiffybag inside your package / envelope containing the receiver - you might also want to consider postage insuance...

On the software side they say please leave the reciever on it's defaults - there is little or no advantage in enabling Sirf curently and Egnoss will be used automatically if your mapping software uses it.

For those who need their details their website is www.holux-uk.com (but this is currently down and their address is :

Holux UK
Lady Lea Industrial Estate
Lady Lea Road
Horsley
Woodhouse
DE7 6AZ
Tel: 0870 3215929

Finally again thanks to all at Holux UK for sortign me out so promptly and without any hesitation.

DinAlt

ocio · Occasional Visitor Joined: Jan 08, 2004 Posts: 10

this procedure id good for international user too ?

i'm in italy , can i sand them cash for shipping ? or other way is better ?

DinAlt · Posted: Fri Jan 09, 2004 6:09 pm Post subject:

Hi again Ocio,

It's probably best if you give them a ring first but they were categoric that they will do this for anyone as long as the user pays all shipping - they are ofering this service because they don't want users of Holux products to feel let down.

DinAlt

Hamie · Regular Visitor Joined: Dec 30, 2003 Posts: 177

Just a little warning about leaving the unit on its defaults. EGNOS can make the position fix WORSE not better in some situations. Especially since EGNOS is still in testing and won't be considered live for a good few months yet.

A better bet would be to DISABLE SBAS (i.e. EGNOS/WAAS) until it's really live & is kicking out good info.

Hamish.

DavidW · Posted: Sun Jan 11, 2004 4:36 pm Post subject:

I think the days of EGNOS making position information worse are behind us - that was in the days where there were insufficient RIMs (monitoring stations) being used to get good differential corrections.
I'd think that by the time an EGNOS signal is receivable again in the UK, there'll be sufficiently many RIMs in use that this is no longer a problem. At the moment, there's no usable signal - the only geostationary satellite currently transmitting an EGNOS signal is IOR (PRN131) which is so far west it's virtually on the horizon in the UK.

It is possible to pick up at least one of the WAAS satellites in the UK (PRN122 if I remember rightly) - that data won't contain iono corrections for the UK (which is the major source of error), but it may help your position fix slightly because of the other transmitted corrections. I would regard this as near certainly harmless even if it won't actually help.

David

Hamie · Regular Visitor Joined: Dec 30, 2003 Posts: 177

As long as they're still in test mode I wouldn't rely on the corrections being any better than no SBAS at all. Check the estb status pages for more info.

There will certainly be times when the corrections are providing better accuracy, but while in testing there will also be times when then NOT providing better accuracy. Don't rely on the GPS output accuracy predictions either to let you know whether the corrections are doing any good. The only real way to tell is to fix a unit in place & log the data...

DavidW · Posted: Tue Jan 13, 2004 12:33 am Post subject:

The ESA status page is http://esamultimedia.esa.int/docs/egnos/estb/schedule.htm - looking at the graphic part way down that's headed "ESTB and EGNOS satellites expected broadcasting plan" is the most useful.

Forget about PRN131 - IOR is far too low to the horizon in the UK to be receivable.

Apart from that, if you look, no satellites are intended to be broadcasting anything worse than EGNOS/SIS-1 level information from now on - which is 15 RIMs - unless they bring Artemis (PRN124) online with a ESTB signal. EGNOS/SIS-1 shouldn't give the problems the ESTB test signal did at times of worsening the quality of the fix you had - and hopefully even an ESTB signal these days shouldn't worsen the quality of your fix because of the number of RIMs in use. If you look at the data at http://esamultimedia.esa.int/docs/egnos/estb/results.htm for the end of December 2003, they're typically using 16 RIMs now.

Unfortunately they are behind schedule in at least some regards since they prepared that chart - PRN126 isn't transmitting any EGNOS data. Overall, the EGNOS web site is a bit of a mess - it takes a lot of searching to find some pieces of information and it can take ages to find things you know are there again. There's also some bits of it that are simply out of date.

The most up to date information is in the latest EGNOS Newsletter - see http://esamultimedia.esa.int/docs/egnos/estb/newsletters/EGNOS_News_Dec_2003.pdf for that. On page 4, it says that the only satellite transmitting as of the end of December is PRN131. On page 2, there's an updated version of the graphic you see on the page I mentioned at the beginning of this post.

I appreciate that there were times during 2003 when turning on SBAS and receiving a test EGNOS signal worsened the fix. I very much doubt that that will be the case from now on - though it is always possible until EGNOS reaches full operational capacity and the "test" flag is removed from the signal.

As you say, the only way to know how good the test EGNOS signal is working is to test it! The corrections certainly may be no better than no SBAS, but the main concern is whether they're making things worse than no SBAS. Of course, as all the financial adverts say, past performance is no guarantee of future results.

As it happens, I have the SBAS setting on my non-Holux GPS turned off. However, considering the problems that people have had with 'lost' GR-230 receivers, I would suggest to people not to worry about changing the setting. The chances that having SBAS enabled is going to make things much worse than having it disabled now is low - and I would argue not worth the risk of 'losing' the GPS.

David

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