What does IRS stand for?

• A. Integrated Reference Sensor
• B. Inertial Reference System
• C. Inertial Reference Sensor
• D. Intertial Radiation System

Answer: (B)

IRS stands for Inertial Reference System. This is a navigation setup that creates a reference frame using internal sensors—typically gyroscopes and accelerometers—to determine orientation and movement without relying on external signals. It provides attitude information (roll, pitch, and yaw) and supports navigation by tracking how the platform rotates and accelerates over time. Because it operates independently of external references, it’s a self-contained reference that’s especially valuable when other nav inputs aren’t available, though it can drift over time and may need periodic alignment.

The other options don’t fit. Integrated Reference Sensor isn’t the standard term for the whole navigation setup IRS represents. Inertial Reference Sensor would imply a single sensor rather than the full system. Intertial Radiation System is not a recognized term in this context and is misspelled.