Just asking...

Satellite connectivity is fundamental in ensuring you have good GPS. This in turn ensures you can fly happily in P-Mode and not Atti Mode. The App, UAV Forecast indicates how many Satellites are available and if it is good to fly, this is also dependent on cloud cover..

yes, cloud cover can affect GPS availability.

It can depending on the density of the cloud

Everything I've ever read says that cloud cover has little to no effect on the GPS signal.  Buildup of ice, snow, or water can affect it, but generally speaking clouds (even dense ones) do not.

KlooGee, with all due respect to your work and research, clouds can affect GPS. It depends on the cloud, density, electeical charge, etc. It's not like having 0 satellites, but still, it's affected.

even thick clouds affect gps reception close to zero, it is negligible, so no it does not affect your gps connection.

A few days ago I was out flying before it started raining (the sky was completely covered with clouds), and it seemed to me that I had worse GPS reception than I usually have. Now we all know that in-car sat nav systems seem to work just fine, even during very bad weather, but maybe they don't need very good reception to function properly, unlike the Spark. An in-car sat nav probably has a lot more time to determine its position, and doesn't have to know it with the same accuracy either.

Take a look at the SUPPORT section of GPS.gov

This section talks about GPS accuracy:
https://www.gps.gov/systems/gps/performance/accuracy/

dj_dread Posted at 2018-4-16 14:12
KlooGee, with all due respect to your work and research, clouds can affect GPS. It depends on the cloud, density, electeical charge, etc. It's not like having 0 satellites, but still, it's affected.

I'm not saying I know the answer definitively, but below are some examples citing what I've read in the past.    I'm always interested in learning.  Do you have some sources I can review to back up your statement?

US Military (item #8):  http://airforcelive.dodlive.mil/ ... hs-surrounding-gps/

US government that manages GPS system don't list cloud cover as a problem:  https://www.gps.gov/systems/gps/performance/accuracy/

Racelogic that makes precise timing instruments:  https://racelogic.support/01VBOX ... ather_affect_GPS%3F

http://www.gpsreview.net/10-myths-about-gps/  

http://gpsinformation.net/gpsclouds.htm

http://www.ictir11.org/4-interes ... dnt-know-about-gps/

KlooGee Posted at 2018-4-16 17:54
I'm not saying I know the answer definitively, but below are some examples citing what I've read in the past.    I'm always interested in learning.  Do you have some sources I can review to back up your statement?

US Military (item #8):  http://airforcelive.dodlive.mil/2015/03/10-common-myths-surrounding-gps/

Also, keep in mind that the number of visible satellites for a given location is not static.  It changes on an hourly basis.

The following site predicts how many satellites are visible at a given time and location.

http://satpredictor2.deere.com/address

KlooGee Posted at 2018-4-16 17:57
Also, keep in mind that the number of visible satellites for a given location is not static.  It changes on an hourly basis.

The following site predicts how many satellites are visible at a given time and location.

definitely what you posted is right.
i can tell, from my experience of driving with a gps device. yes, you may say that moving fast, long distances, can affect GPS availability. but it happened several times, that during a very cloudy day, and i am talking about a very low and dense cloud ceiling, the device could not lock any GPS.
at that time i found this:
https://books.google.ro/books?id ... ference&f=false

this one mentions accuracy and list "atmospheric conditions" among the factors that can affect accuracy:
https://www.gps.gov/systems/gps/performance/accuracy/

https://cellphonetrackers.org/9- ... oning-accuracy.html

from what i read so far, it seems there are 2 groups: 1 saying clouds do not affect GPS, while other say clouds and bad weather can affect. probably it's a combination of factors, starting with solar storms, space particles, clouds electricity and the device itself.

I agree that from what I've read there are 2 groups in the same that you mention.  I've read lots of anecdotal accounts mentioning clouds affecting their usage.  However, most of the reliable sources I've read indicate that clouds have little affect.  Below is another reference from a company named Trimble that specializes in location based technologies.  Again, I'm not an expert in this area.  Just passing along what I've read.

http://www.trimble.com/gps_tutorial/howgps-error.aspx
http://www.trimble.com/gps_tutorial/howgps-error2.aspx

Typical Error in Meters (per satellites)	Standard GPS	Differential GPS
Satellite Clocks	1.5	0
Orbit Errors	2.5	0
Ionosphere	5.0	0.4
Troposphere	0.5	0.2
Receiver Noise	0.3	0.3
Multipath	0.6	0.6

Ionosphere

The ionosphere is the layer of the atmosphere ranging in altitude from 50 to 500 km.

It consists largely of ionized particles which can exert a perturbing effect on GPS signals.

While much of the error induced by the ionosphere can be removed through mathematical modeling, it is still one of the most significant error sources.

Troposphere

The troposphere is the lower part of the earth's atmosphere that encompasses our weather.

It's full of water vapor and varies in temperature and pressure.

But as messy as it is, it causes relatively little error.

There are a couple of ways to minimize this kind of error. For one thing we can predict what a typical delay might be on a typical day. This is called modeling and it helps but, of course, atmospheric conditions are rarely exactly typical.

KlooGee Posted at 2018-4-17 05:30
I agree that from what I've read there are 2 groups in the same that you mention.  I've read lots of anecdotal accounts mentioning clouds affecting their usage.  However, most of the reliable sources I've read indicate that clouds have little affect.  Below is another reference from a company named Trimble that specializes in location based technologies.  Again, I'm not an expert in this area.  Just passing along what I've read.

http://www.trimble.com/gps_tutorial/howgps-error.aspx

thank you for the extensive research KlooGee!
probably each person will see if clouds are really affecting GPS reception and accuracy based on personal experiences afterall. all these studies may not cover all the possible scenarios, locations, etc.
nevertheless, this was a good and productive discussion that can be saved for further reference.