Kustom Signals Golden Eagle II Operator's Manual page 29

Section 5--General Theory of Operation
Golden Eagle II would process the groundspeed of 55 MPH
and the combined speed of 120 MPH. The DSP would
subtract the patrol speed from the combined speed (120 -
55 = 65). The PATROL window would display 55 and the
TARGET window would display 65.
In the Moving Same Direction mode of operation, the
target Doppler is received from a target traveling in the
same direction as the patrol vehicle. These "groundspeed"
Doppler and the "difference" Doppler signals are received
and sent to the DSP. The Difference Doppler is the speed
difference between the patrol vehicle and a vehicle
traveling in the same direction. If the Golden Eagle II is
equipped with DCM antennas, it is capable of
automatically determining if the target vehicle is traveling
faster or slower than the patrol vehicle. The unit will
display the patrol speed then automatically add or subtract
the "difference" speed to the patrol speed for the target
speed.
If the patrol vehicle's speed was 55 mph and a target was
traveling in the same direction at 70 mph, the Golden Eagle
II would display 55 in the PATROL window then add the
"difference" Doppler signal (15) to the patrol speed (55 +
15 = 70) and display 70 in the TARGET window.
5.2