In navigation, infrared is used to provide which of the following?

• A. Altimeter
• B. Gyroscope
• C. Ground speed indicator
• D. Compass

Answer: (C)

Infrared sensing in navigation is used to determine how fast you’re moving over the ground. An infrared system can observe the ground scene or a known ground beacon and measure how quickly features move past the sensor. By tracking this relative motion, the navigation system derives your speed relative to the surface below, which is presented as the ground speed indicator.

This isn’t about measuring altitude with air pressure, rotation with a gyroscope, or magnetic direction with a compass. Those sensors serve different purposes, while the infrared approach focuses on relative motion between the vehicle and the ground, giving you ground speed.