SCXmechanic From United States of America, joined Dec 1999, 534 posts, RR: 1 Reply 1, posted (11 years 11 months 3 weeks 6 days 1 hour ago) and read 2450 times:
It used several ground stations based around the world and transmitted a low freq signal that was used for Long Range Nav. But wasn't very accurate and could easily have been distorted by solar flares. Its since been decomissioned by the Navy (I think thats who ran the system as it was used by surface ships too)
Modesto2 From United States of America, joined Jul 2000, 2631 posts, RR: 6 Reply 3, posted (11 years 11 months 3 weeks 5 days 11 hours ago) and read 2414 times:
I got another word (or acronym)...
Intertial navigation system. Punch in coordinates at gate and with a system of accelerometers, it tracks the aircraft's movement. Even now, aircraft use an IRS (inertial reference unit) that is similar to the INS to back up the GPS.
JT-8D From United States of America, joined Dec 2000, 423 posts, RR: 3 Reply 4, posted (11 years 11 months 3 weeks 5 days 11 hours ago) and read 2405 times:
Well, your right to a point. The irs does more than provide position data. On our planes, the fmc position is the "accepted" position. It gets data from the gps, and irus. It will update its position from gps, but not from iru. Irus main job is provide output to instruments (hsi, adi, vsi,)..JT
TimT From United States of America, joined Jun 2001, 168 posts, RR: 0 Reply 5, posted (11 years 11 months 3 weeks 3 days 22 hours ago) and read 2368 times:
The airline I work for uses Inertial Navigation on some of the planes. The INU has 2 accelerometers and a clock. It all runs off of an internal computer/database and then updates within 150 miles of a DME site. The DME's usually read in pairs and like a 90degree angle. It calculates the position and updates. The accelerometers are sensitive enough to read the earth's rotation. We havin' fun yet??