Question

Which optical scanner has a rotating scan mirror to scan the Earth perpendicular to the satellite track?

• A. Across Track Scanners
• B. Along Track Scanners
• C. Frame Cameras
• D. Radar scanner

Hint:

Scanner types: \[ \boxed{ \begin{aligned} \text{Across-track (Whiskbroom)} &\rightarrow \text{Rotating mirror} \text{Along-track (Pushbroom)} &\rightarrow \text{Linear detector array} \end{aligned} } \]

Answer 1

The Correct Option is A

Concept: Across-track scanners (whiskbroom scanners) use a rotating or oscillating mirror to scan the Earth's surface perpendicular to the direction of satellite motion.

Step 1: Understand the scanning mechanism.
• Across-track scanner $\rightarrow$ Rotating mirror scans across the flight path.
• Along-track scanner $\rightarrow$ Uses a linear detector array without a rotating mirror.

Step 2: Identify the correct scanner. Thus, \[ \boxed{\text{Across-track scanners use a rotating scan mirror}.} \] Therefore, the correct option is \[ \boxed{(A)\;\text{Across Track Scanners}.} \]