What is the function leading edge range tracker servo loop?

A)
Speed measurements
B)
Vertical speed measurement
C)
Automatic ground navigation
D)
Provide range to the nearest return

Correct Answer :   Provide range to the nearest return


Explanation : To provide a range to the nearest return within the bounds of the antenna beam, many modern radar altimeters incorporate the gate in a pulse modulated radar or a filter in a frequency modulated radar over the leading edge of the return.