Question About Satellite Signals

[stang buff]

I have a question about a GPSr and satellite signals. I've seen a lot of comments about tree cover and cloudy days causing poor reception of satellite signals. I can understand that follage could cause poor reception...it's happend to me a lot. But, do clouds really affect reception? I wouldn't think so, but I don't know for sure.

[Alphawolf]

I have never found clouds, rain or snow to keep me from getting sat. lockup.

[+Prime Suspect]

I have a question about a GPSr and satellite signals. I've seen a lot of comments about tree cover and cloudy days causing poor reception of satellite signals. I can understand that follage could cause poor reception...it's happend to me a lot. But, do clouds really affect reception? I wouldn't think so, but I don't know for sure.

They specifically chose a frequency range for the GPS system that isn't affected by cloud cover. Anecdotal evidence to the contrary is just that, anecdotal.

[+Renegade Knight]

...Anecdotal evidence to the contrary is just that, anecdotal.

Bingo.

 

I'm one of the owners of some ancedotal evidence, but after being pointed to some white papers on the subject by people who know more than I do about these things I have learned that could cover is not an issue. However having had a very bad day of caching in heavy cloud cover and fog where every cache was off by 50-60', I'm hoping to get back out there and see if it was one bad day or if my obsevation is something that I can repeat. Finding that combo of coud cover and fog though is hard.

[+GOT GPS?]

Seems to me like the issue would be wet trees, for the signal maybe blocked by thick wet foliage.

[+Renegade Knight]

Seems to me like the issue would be wet trees, for the signal maybe blocked by thick wet foliage.

You know, I think you have something there.

[Neo_Geo]

Check THIS THREAD!

 

This is about a kind of a benchmark cache where cachers post their reported coordinates and weather conditions.

 

CLICK HERE to view the cache page.

 

It all goes to show that clouds do not affect the signal.

 

See THIS PAGE too!

Edited October 31, 2004 by Neo_Geo

[+NimravusHSSR]

I think it has to do with the unit alot too. When I turn on my 60cs and Rino 130 inside my house, the 60cs immediately picks up signals and locks with no problem

 

The Rino takes longer and has trouble keeping the signal. I don't have any problems aquiring signals under any foliage but other GPSrs do, standing in the same spot.

[+lakedawgs]

Interesting stuff from GPSinformation.net

http://www.gpsinformation.net/gpsclouds.htm

Good thread,

Lakedawgs

[+Marky]

However having had a very bad day of caching in heavy cloud cover and fog where every cache was off by 50-60', I'm hoping to get back out there and see if it was one bad day or if my obsevation is something that I can repeat.

I've had days like this with clear blue skies. Sometimes, the satellite configuration is bad, which usually takes a while to change. I've seen days where all the satellites in view were nearly in a straight line. Hard to get a good triangulation from a configuration like that.

 

--Marky

[+SKYWLKR]

I have never lost a signal to clouds or trees or rain....

 

I can even get a good lock (3-4 sats)from inside my house... in the rain.

[+Searching_ut]

Many years ago, when I worked in a USAF test squadron, I got to look over a bunch of data that had been collected regarding atmospheric effects on GPS signals. The effects of the lower atmosphere on signal strength, and speed/direction were virtually non existant. The atmosphere above the cloud layers however can, and often does affect the signal significantly, to the point it will be quite noticable with a consumer GPS unit.

 

It's been quite interesting watching the discussions of cloud cover or rain on GPS performance over the years though. An awful lot of people swear it makes a very noticable difference, others see none at all. Is it a case of people seeing what they expect to see, or could the assorted measurments and measurment techniques be somehow in error? My own thoughts are that to a large extent, peoples perceptions of how their units perform is driven by expectation. It's very interesting none the less. My own observations are that clouds, rain, and snow don't have any noticable effect.

[+NightPilot]

I think it has a lot to do with uncontrolled variables. On one cloudy day, the accuracy was poor, so it's assumed that the clouds caused the inaccuracy, when in fact something else may have caused the problems and the clouds were only coincidental. Before we start blaming something for a problem, we need to eliminate all the other possible causes. If I try to start my car on a foggy day and the battery is dead, is it at all certain that the fog killed the battery? It might behoove me to look for other possible causes.

[+apersson850]

My own idea about this is the same as was pointed out above: On a cloudy and foggy day, the probability that the foilage is wet is higher. And wet foilage does attenaute the signals. So it's not the clouds themselves, but the effect they may have on other circumstances.