ie. if it's in my pocket, & the first time I get it out to use is in said Sudan? will it give me my long & lat (assuming I have a map?)
john.
Yes, it should... but(!) It will need a decent view of the sky (ie sattelites!) and if the unit still thinks it's in Huddersfield or wherever it will initially be looking for the wrong sattelites so will take some time to give you an accurate location (some units will claim up to 20 minutes but it varies depending on location and unit).
I use a wrist mounted Garmin at work as it's *very* small and light and I don't need maps, bells whistles etc, I just need an accurate location fast. Haven't found any blank spots on military areas, but then I'm not after electronic maps, just the spot location.
You also need to be aware that if you are in a conflict zone, especially one involving US or NATO forces, there is a fair risk that the Americans will have disabled, or intorduced a large error into, the civilian GPS system (it's a fair one, they paid for it, why should they let potential opposition use them!).
In Yugoslavia during parts of 1998/99 it showed itself with civilian GPS's flicking randomly one grid square side to side and sometimes failing to produce a steady location...
btw, Andy, if you have a spare hour or two a short video or slideshow of how the sun compass works would be very interesting indeed
