Radio navigation is a process or technique used for directing the movement of a vehicle from one position to another along the desired trajectory (direction). The processing unit receives inputs from the on-board vehicle motion sensors and other navigational aids. The processing unit provides information to the pilot in the form of displays and also generates required commands for the control system to keep the vehicle along the desired trajectory. Loran is short-form of ‘Long range navigation aid’. It is based on measurement of the difference in the time of arrival of electromagnetic waves from two transmitters to the receiver in the craft. The receiver finds out the time difference between the time taken by master pulse to reach the receiver and time taken by slave pulse to do the same. The exact location may be determined by drawing another line of position due to a second pair of transmitters.