The conical shock wave of a projectile traveling faster than the speed of 
sound intersects three microphones.  From the arrival time differences 
between the microphones, extrapolate the origin and destination of the 
projectile.

Excel 97 Workbook Solution:
http://www.geocities.com/jongiff2000/aa707.xls

Standard Web Site Solution:
http://mypeoplepc.com/members/jon8338/math/id22.html

I have made several attempts at this problem.  This time I checked the 
results and they fit.  Some inputs are impossible and lead to corrupt 
results.  The Worksheet will solve the problem for any reasonable inputs.

For instance, if the microphones are placed at the corners of an equilateral 
triangle 10 feet apart and the projectile travels at Mach 4, it is 
impossible for the time differences to be minutes.  They are more like in 
the order of milliseconds.

Jon Giffen