MIT ICAT Inertial Reference Unit Integrate acceleration from known position and velocity 口 Velocity 口 Position Need Heading 口 Gyros Mechanical Laser Can get Attitude a Artificial Horizon(PFD. HUD) Drift errors D IRU unusable in vertical direction (need baro alt) 日 flight Correction DME GPS Star Sighting for Space Vehicles Measurement Give Attitude also Z77 Analytical RedundancyMIT ICAT Inertial Reference Unit y Integrate acceleration from known position and velocity † Velocity † Position y Need Heading † Gyros ‹ Mechanical ‹ Laser y Can get Attitude † Artificial Horizon (PFD. HUD) y Drift Errors † IRU unusable in vertical direction (need baro alt) † Inflight Correction ‹ DME ‹ GPS ‹ Star Sighting for Space Vehicles y Measurement Give Attitude Also y 777 Analytical Redundancy