Archived posting to the Leica Users Group, 2004/06/17
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]> > > No major airports in the vicinity but you are absolutely correct. > > Closer inspection showed it to be the 'Property of Air Traffic Control Systems'. > > That's a VORTAC. A VORTAC is a VOR and a TACAN in the same building. > > A VOR is a VHF Omnidirectional Ranging beacon. > VHF is the name of the radio frequency used. > Omnidirectional means it sends in all directions (that's why it has that ring of antennas around it). > Beacon means it sends to you, rather than you sending to it. > > VORs send airplanes signals that the airplanes can use to navigate. > > A TACAN is a TACtical Air Navigation station. It sends VOR-like signals on a different frequency, and responds to DME (Distance Measuring Equipment) probes from airplanes equipped with it. In other words, a DME-equipped airplane can hear a TACAN, send out a probe saying "How far away am I?" and get an answer back from the TACAN. > > If I were a Very Bad Person and I wanted to make the world stop, I would coordinate the destruction of a bunch of VORTACS. Airplanes wouldn't be able to fly so well any more. > We would hardly notice. Most modern planes use inertial navigation with occasional position updating . That can be from star trackers.Visual landmarks ,indeed DME,s and usually GPS.\best regards simon