Maximum Unambiguous Range Calculator

The unambiguous range of a radar is the maximum range at which a target can be located so as to guarantee that the reflected signal/pulse from that target corresponds to the most recent transmitted pulse. The radar range is measured by the time delay between pulse transmission and reception. It is Usually assumed that the received pulse is associated with the most recent transmitted pulse. Targets at ranges beyond the unambiguous range therefore appear closer because the received pulse will correspond to the previous transmitted pulse. This situation can be avoided by coding of the pulses which can differentiate between the most recent transmitted pulse and earlier ones, enabling the measurement of ranges beyond the "unambiguous range". This range is dependent on the pulse repetition time (PRT) of a radar or the pulse repetition frequency (PRF) which is 1/PRT.

Maximum Unambiguous Range

Note: The Pulse Repetitive Frequency (PRF) is 1/(PRT i.e Pulse Repetition Time)


  • Unambiguous Range

Calculation of Radar Unambiguous Range

Radar Unambiguous_Range( In Meters)


C = 3 x 108 m/s (Speed of Light)

PRT = Pulse Repetition Time (In micro seconds)

PW = Pulse Width (This is usually less than 1 micro second and is thus ignored)

Once PW is Ignored the formula can be modified to:



PRF = Pulse Repetition Frequency

C = 3 x 108 m/s (Speed of Light)