For systems intended for transport platforms where the environment is
fairly benign, ruggedized commercial or even pure commercial
may work.

According to the superlative "The March Up" (by Bing West), the
marines in Iraq actually preferred the commercial GPS units to the
military variety.

Not in that book, but probably on TV or in the WSJ, I recall that one
U.S. officer had his mother mail him a store-bought GPS unit.

I recommend The March Up. www.warbirdforum.com/marchup.htm

all the best -- Dan Ford
email: www.danford.net/letters.htm#9

see the Warbird's Forum at www.warbirdforum.com
and the Piper Cub Forum at www.pipercubforum.com