The time interval between the transmission of a given DME interrogation pulse and the reception of the appropriate response pulse at the aircraft is 2 milli seconds. The slant range is:
Time interval = 2 mili sec
Speed of radio wave = 3 x 10^8 m/s
Distance traveled by the pulse in 2 mili sec = (2 x 10^-3) x (3 x 10^8) m = 6 x 10^ 5 m = (6 x 10^5) / 1852 nm = 323.9 nm
In 2 mili sec the pulse has traveled from the a/c to the ground station and back to the a/c.
323.9 nm = distance traveled by the pulse from the a/c to the ground station and back to the a/c.
So distance (slant range) of a/c from ground station = 323.9/2 = 161.9 nm
Last edited by gAMbl3; 13th Apr 2012 at 17:31.
Reason: Typo