Question

Which among the following techniques is employed in long range navigation (LORAN)?

(a) Round trip time of a radio pulse

(b) Time difference between two radio pulses

(c) Phase difference between two continuous signals

(d) Phase difference between the transmitter and the receiver

The question was posed to me in a job interview.

Query is from Next Generation Wireless Network topic in section Next Generation Wireless Network of Cognitive Radio

Answer 1

Correct choice is (b) Time difference between two radio pulses

To explain I would say: Long range navigation is a hyperbolic radio navigation system operating at low frequencies. The hyperbolic navigation system in LORAN uses the time difference between radio pulses to locate the object of interest. An electronic clock was employed to generate trigger signals that maintain a fixed delay such as 1 ms between the transmitters.