Using Gps In A Snow Storm?

[+Milbank]

There have been times were I have had to go out in a snow storm for work.

Often times it's after dark and very hard to see more then a few feet.

 

I did not have a gps last winter, but now I'm wondering will my gps work in these type of conditions?

 

It would be great if I could count on my gps in a snow storm to let me know if the next road coming up is the one (no street signs around here) I want to take or not and how far away it is.

[+EraSeek]

Gps works fine in snow, rain, sleet, clouds, and the like. I used mine before in a few whiteouts on Mt Rainier.

 

Here is what the experts have to say:

 

"Rain, Snow, Clouds and GPS Reception

1) Does RAIN or SNOW or CLOUDS affect the reception of my GPS receiver?

Answer: No. Not so as the user can tell without instrumentation.

 

2) I notice that when it rains and I turn on my windshield wipers my GPS has trouble locking. Doesn't this mean that rain affects my GPS reception?

Answer: No. What is affecting your GPS signal reception is the fact that the wipers running back and forth across your windshield is intermittently blocking reception and making it difficult for your GPS to get a complete navigation data string. Turning off your wipers until the signal locks will speed the initial lock.

 

3) Sometimes my GPS gets a thick coating of water on it and it does not receive as well. Does this not prove that rain can cause signal degradation?

Answer: No. A coating of water, even a fairly thin one is NOT the same as raindrops. The GPS signal frequency of about 1575mhz was chosen expressly because it is a "window" in the weather as far as signal propagation is concerned.

 

4) This all sounds good, but do you have a reference that supports these statements?

Answer: Yes.

See: Ref: http://www.navcen.uscg.gov/pubs/gps/sigspec/default.htm (Courtesy of Sam Wormley)

 

Cloud, Rain, Snow, weather in general does NOT attenuate the GPS signals enough to effect accuracy. As can be seen below, the total atmospheric loss (from all causes including rain, clouds, snow, fog, etc.) is but 2db. This is small compared with other variables.

 

L1 and L2 Navigation satellite Signal Power Budget

 

Parameter L1 P-Code L1 C/A-Code L2 P-Code

-----------------------------------------------------------------------------------------------------

User minimum received power -163.0 dBw -160.0 dBw -166.0 dBw

Users linear antenna gain 3.0 dB 3.0 dB 3.0 dB

Free-space propagation loss 184.4 dB 184.4 dB 182.3 dB

Total atmospheric loss 2.0 dB 2.0 dB 2.0 dB

Polarization mismatch loss 3.4 dB 3.4 dB 4.4 dB

Required satellite EIRP +23.8 dBw +26.8 dBw +19.7 dBw

Satellite Antenna gain at 14.3° 13.5 dB 13.4 dB 11.5 dB

worst case Block II off-axis angle

Required minimum satellite antenna +10.3 dBw +13.4 dBw +8.2 dBw

Input power 10.72W 21.88W 6.61W

 

5) Ok then, can I use my GPS underwater?

Answer: No. Just a few millimeters of "solid" water will severely attenuate the GPS signal.

 

Joe Mehaffey "

[Jamethiel]

No problems last winter here in Montana. Just remember to keep extra batteries on hand -ours seemed to die faster in the cold. And we've found that those handwarmers that are packaged for hunters are a wonderful thing on long hikes. For us, not for the GPSr.

-Jennifer

[+EraSeek]

Use Lithium batteries. They are made to work in the cold. Others may fail ya.

Edited July 28, 2004 by EraSeek

[Jamethiel]

Use Lithium batteries. They are made to work in the cold. Others may fail ya.

Lithium is what we've gone to for all our electronics now (after I read a thread about them last winter). They really did make a difference.

-Jen

[+Milbank]

Glad to here the gps will work in the snow.

Thanks,

[+Larry.s]

We use them to find our spots when ice fishing and they work fine even when caught in an unexpected snowstorm. I just try to keep it inside my outer layer of clothes as much as possible to keep it warm when I'm not using it. I keep it in a cell phone holder glued to the gas tank of my Ski-Doo when using it to navigate to our spots or back to the truck.

[+Ambrosia]

Hey, they used a gps in the middle of a truck, in a major snow storm, in the "The Day After Tommorow"!

[+Metro Nomad]

Hi Milbank

 

I've used my GPS in heavy fog where you can hardly see the road. If you have a pre-recorded track loaded in the GPS, it is rather eerie to see the pointer moving to show upcoming bends.

 

Found it to be very effective, not to mention re-assuring.

[+The Jester]

No problems last winter here in Montana. Just remember to keep extra batteries on hand -ours seemed to die faster in the cold. And we've found that those handwarmers that are packaged for hunters are a wonderful thing on long hikes. For us, not for the GPSr.

-Jennifer

One of the handwarmers around the battery compartment (use a couple of 4x4 dressings, with some tape - air has to get to the handwarmer, the 4x4s also act as insulation) will keep the batteries working quite a bit longer. So they are good for both of you! This can work for cameras, cell phones, etc.

[+Torry]

My little yellow eTrex is cranky in ANY kind of weather. Rain, snow or cloudy are all the same for me.

[+CO Admin]

Just dont totaly depend on the GPS, if the map you use is a little wrong then you can drive off a cliff. Happened in CO last year. + you are generaly a sec behind on your position.

Just a thought

[+cache_us_if_you_can]

Our GPSr has always worked very well in bad weather (ie: snowstorms, thunderstorms, rain... etc). Just remember the best advise:

Just dont totaly depend on the GPS