From two radar sweeps, which quantities’ rate of change is used to derive a target's course and speed?

From two radar sweeps, which quantities’ rate of change is used to derive a target's course and speed?

• A. Range and bearing
• B. Altitude and depth
• C. Latitude and longitude
• D. Color and brightness

Answer: (A)

The movement you infer from two radar sweeps comes from how fast the target’s range and its bearing are changing. The range rate (dr/dt) tells you how quickly the target is moving toward or away from the radar, while the bearing rate (dθ/dt) tells you how quickly its direction around the radar is changing. Together, these two rates define the velocity vector relative to the observer, from which you derive the target’s speed (the vector magnitude) and course (the direction of that velocity). The other options describe static coordinates or non-motion properties, which don’t inform how the target is moving between sweeps.

The movement you infer from two radar sweeps comes from how fast the target’s range and its bearing are changing. The range rate (dr/dt) tells you how quickly the target is moving toward or away from the radar, while the bearing rate (dθ/dt) tells you how quickly its direction around the radar is changing. Together, these two rates define the velocity vector relative to the observer, from which you derive the target’s speed (the vector magnitude) and course (the direction of that velocity). The other options describe static coordinates or non-motion properties, which don’t inform how the target is moving between sweeps.