Direct light propagation time Distance can be measured directly by sending a pulse and measuring how it takes to travel between two points Most common method is to reflect the signal and the time between when the pulse was transmitted and when the reflected signal returns System used in radar and satellite laser rangIng 02/25/02 12.540Lec0602/25/02 12.540 Lec 06 4 Direct light propagation time • Distance can be measured directly by sending a pulse and measuring how it takes to travel between two points. • Most common method is to reflect the signal and the time between when the pulse was transmitted and when the reflected signal returns. • System used in radar and satellite laser ranging