IR stands for inertial reference, a self-contained navigation method that calculates an aircraft's exact position, velocity, and orientation without relying on external signals like GPS. The system measures linear and angular acceleration from a known starting point to track movement continuously. Pilots and avionics rely on this data to maintain accurate heading and attitude displays, especially when satellite signals are lost or jammed.
Heard on the job
We lost GPS on the right side, but the IR is still giving us a solid position.
Insider tip
Commercial airliners usually have three independent IR units to provide redundancy, allowing the flight management computer to vote out a faulty sensor if one starts drifting.
Also heard as
- IRS
- inertial reference system