•The
 HawkEye system works with a 200Hz laser.
 •The
 laserbeam is transmitted through a mirror system to the scanning mirror which
 sends the pulses down to the watersurface. 
•The laserpulse contains of 80%IR
 and 20%green light. The IR component of the pulse is reflected in the
 watersurface back to the helicopter. The green light penetrates the
 watervolume and is reflected at the bottom. 
•There are three detectors for the
 returning pulses, one for the IR and two for the green light. The reflected
 pulses are digitized and the time between the IR and the green pulse is
 measured. With that time the depth can be determined.
•The
 scannermirror has encoders witch gives very accurate angles for the beam.
 These angels are used to calculate the position of the lasershots relative to
 the helicopter. In order to stabilize the mirror for helicopter motions the is
 an IRS system connected to the mirror. 
•The helicopter it self is
 positioned with DGPS. We have two possibilities to get differential
 corrections. One is through our IALA standard radiobeacons and our other
 possibility is through the national EPOS service. The EPOS service is
 transmitted on the FM band.