It requires five receiver channels and additional electronics , an expensive requirement when it was introduced .
It differed from VOR primarily in its modulation system , adding a Lorentz - like signal to accurately define the center of the rotating beam and thereby improve accuracy .
VOR requires five receiver channels and additional electronics , an expensive requirement when VOR was introduced .
It differed from VOR primarily in its modulation system , adding a Lorentz - like signal to accurately define the center of the rotating beam and thereby improve accuracy .