What components are contained within each IRU to measure inertial motion?

The correct answer consists of accelerometers and laser gyros, which are critical components in an Inertial Reference Unit (IRU) for measuring inertial motion. Accelerometers are used to measure the linear acceleration forces acting on the unit, determining how the object moves in three-dimensional space. This measurement allows for the calculation of change in velocity and position over time.

Laser gyros, on the other hand, are utilized to measure the rate of rotation about the unit's axes. They provide highly accurate data on angular displacement, which is essential for calculating orientation and ensuring stability during flight.

Together, these two components enable the IRU to deliver precise information regarding the motion and orientation of an aircraft in real time, without reliance on external references. This is particularly important in environments where GPS signals might be unreliable or unavailable, ensuring the continued operation and navigation capability of the aircraft.

The other options do not encompass the essential components of an IRU for inertial motion measurement. Magnetometers and altimeters, for example, are more involved in external environmental measurements rather than providing inertial navigation capabilities. Similarly, GPS and barometers pertain to position fixing and altitude measurement, respectively, and are not intrinsic to the inertial measurement process within an IRU.