How does GPS work?

[Ujamaflip]

You can download maps for Russia, or parts of Russia from the Open Street Map project here: http://gis-lab.info/data/mp/#googtrans/ru/en.

Open street map is an open source map formed from user submissions, therefore some parts will be more complete than others. You can see here how complete the areas you wish to visit are: http://www.openstreetmap.org/. Deep Russia doesn't seem particularly detailed but the main roads are there.

Converting the maps into a format ready to download onto your device can be a bit fiddly, but there's lots of advice on the OSM wiki about how to do that. Often people provide ready to use packages on their websites.

Hope this helps!

 

[bikefish]

You have plenty of info about Garmin - also have a look at car satnavs (some hackable to support multiple fonts - eg dual language, lots s/ware on CE, WM) , smartphone gps (low profile, offline google maps, lots apps) - but you will have to charge Li batteries somehow. Any basic gps can give lat/longs but dont expect too much correlation to position on paper eg military pdf maps.http://www.cyclechat.net/forums/faq.php?faq=rules#faq_charityandsupportedrides

 

[CopperBrompton]

it looks as if bringing GPS devices into Russia might be a problem. Anyone had any experience of this?

Done it several times, in Russia, the Ukraine and Belarus and not had any problems.