AH-1000 Product Knowledge What is an AHRU? Flashcards
AHRU
Attitude, Heading Reference Unit
AHRS
Attitude, Heading, Reference System
AH-1000 AHRS Ship Set
2 AHRUs, 2 AHRU mounting rays, 2 External Configuration Modules, 2 Magnetometer units (also called MSU’s, magnetic sensing units)
HG2205AB03 AHRU Product Description
The HG2205AB03 AHRU contains a set of three gyros, three accelerometers, and a microprocessor that computes the AHRU solution. From these it generates pitch and roll attitude, magnetic heading, body rates, and accelerations. Magnetic heading is slaved to an external three-axis magnetometer the KGM 7010.
Why do airplanes have an AHRS?
An AHRS provides the information a Pilot needs to Aviate.
Aviate: What information is needed?
Pitch/Roll/Yaw angles, Pitch rate, Roll rate, Yaw rate, lateral acceleration, longitudinal acceleration, and normal acceleration
Pitch rate
how quickly the aircraft is rotating around the pitch/lateral axis.
Roll rate
how quickly the aircraft is rotating around the roll/longitudinal axis.
Yaw rate
how quickly the aircraft is rotating around the vertical axis.
Pitch, Roll and Yaw angles
these are referred to as the aircraft’s attitudes.
Lateral Acceleration
forces pushing the aircraft sideways.
Longitudinal Acceleration
forces pushing the aircraft forward/backward.
Normal Acceleration
forces pushing the aircraft in the vertical axis.
Inertial Reference Units
Inertial reference units are devices that measure motion in reference to a point in space. AHRU is a type of IRU. It contains sensors like the following:
Gyroscopes – measure rotation (angular acceleration) around an axis.
Accelerometers – measure linear acceleration along an axis.
IRU Nomenclature (Commercial Nav)
IRU/IRS- a navigation grade inertial reference unit/system.
AHRU/AHRS- attitude heading reference unit/system. (not nav grade).
SAHRS- super AHRS, near nav grade AHRS (doesn’t require MSU)
