Hi John,
I have had the same thing, loosing connection etc... one day it happened 10+ times wasn't usually that bad though, every now and again it use to disconnect.
I contacted support and they advised me to try a different USB cable, so I popped down to Maplin bought myself a 3M cable and low and behold I haven't had it disconnect since works 100% FANTASTIC!!! also on a plus not I have extended the cable by 1.5M :)
So I would probably try a different USB cable first :)
P.S. Thanks Airnav Support :)
Ian :)