could 
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then
and
called Global
earth. 
get
meters (on

Thought it means Global Positioning System. There are two precision levels, one  
for army applications (killing has to be very accurate today) and one for civil  
ones. The civil precision is about 20 to 30m (correct me, if I'm wrong),  
though, it may be insufficiant for mapping buildings. But there is a way with  
an additional reference point (e.g. one fixed GPS system in a house) to get the  
same high precision as the military version, but it gets pretty complicated  
then. If You use a microwave system (actually this means some type of radar),  
You need quite a lot of number crunching to get accurate vectorized data out of  
Your original signals. So the GPS system seems to be the better (and running)  
idea for Your application(there have been discussions in this newsgroup, don't  
know of an address anymore).

Cheers    Robert   (HB9NBY) 