+The Targett Family Posted March 2, 2003 Posted March 2, 2003 There was a thread the other day saying that cloud coverage wont interfere with a gps signal. I have recently found out that this is not quite the case. If the clouds are rain clouds then they will, and the more water they are holding the denser the cloud. This means a weaker signal getting through. Is this true? My readings also seem to get a little scudded if I’m near electricity pylons, is this just me or can they have an effect? Is their any thing else that can affect the gps signal I should know? I know about Trees and being indoors The Targett Family Quote
+TheCat Posted March 2, 2003 Posted March 2, 2003 Well being indoors is a no go as far as GPS signals goes. As for the rest I am sure there will be some slight attenuation of signal from dense cloud cover but not enough to loose sat lock. Trees are another matter if there is a dense canopy you can lose lock but it is all part of the fun. A compas comes in handy then unless your GPS has one built in just make sure it is turnned on. Mark (TheCat) www.geocacheuk.com Quote
+The Good Shepherds Posted March 2, 2003 Posted March 2, 2003 quote:If the clouds are rain clouds then they will, and the more water they are holding the denser the cloud. This means a weaker signal getting through. It's true, but even very bad conditions will only cause a very small error - a few feet at worst. The main part of the GPS error is caused by the signal passing through the ionosphere (the layer of ionized particles between 50 - 500km above the earth). The amount of interference caused by the ionosphere changes from day to day. The GPS satellites continually broadcast "forecasts" of how bad the ionosphere occlusion is... but it's not always 100% accurate. To compound problems, the GPS satellites aren't always quite where they should be... and their clocks are sometimes slightly "off". The satellites transmit corrective data to warn your GPS about these inaccuracies (called the "ephemeris"), but it can take 15 minutes for the full message to be sent - so your GPS might not be as accurate as it could be until 15 minutes after you turn it on. The other thing that can cause problems is "reflections" of signals off nearby objects - e.g. cliff faces, tall buildings etc. Attempting to use the GPS in a gorge can cause real problems! Urm... that's all I can remember off the top of my head... Quote
+Lance Ambu Posted March 2, 2003 Posted March 2, 2003 quote:Originally posted by The Good Shepherds: Urm... that's all I can remember off the top of my head... If you want more than is on the top of the Good Sheperd's head try http://www.trimble.com/gps/index.html for a tutorial on all you ever wanted to know and much, much more. And that's a whole lot more than fits into my head Lance It's dark and we're wearing sunglasses. Quote
MCL Posted March 2, 2003 Posted March 2, 2003 quote:Originally posted by Lance Ambu:try http://www.trimble.com/gps/index.html for a tutorial on all you ever wanted to know and much, much more. Yeah. I went there. Had a look. Third page I looked at said 'Weight: 1900lbs (in orbit)' Spheres. hogwash. Piffle and cack. No trees were harmed during the production of this posting, but a large number of electrons were terribly inconvenienced.... Quote
+The Targett Family Posted March 5, 2003 Author Posted March 5, 2003 The site you suggested is gr8, more knowledge than my little pea brain could ever handle. But some good tips on what to watch out for. Thnx again Kids Caches and Mayhem what a day !!!! Quote
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