12 January 2016

Thank for dr. martin chow, I had learnt the early positioning system based on TDOA technique such as Loran-C and OMEGA Navigation System. 

Loran-C is the radio navigation system for use on merchant ships. Generally, it seems to be a “Start” pulse when the master signal is revived. Then, it is a “Stop” signal when the secondary transmitter signal received. The time difference from “Start” to “Stop” is a constant. Based on the constant time difference value, it can plot a hyperbolic curve between signals from two stations. The position can be found by more hyperbolic.

OMEGA is the first radio navigation system in global-range and  need to use atomic clocks for synchronizing. Omega used to determine the transition time between transmitter and receiver. Then, it use hyperbolic geometry to find the target position.