North Carolina RADAR State Practice Exam

What is the equation for calculating Target Speed when moving in the opposite direction with a front antenna?

1. TS = PS + CS

2. TS = CS - PS

3. TS = SS + PS

4. TS = PS - SS

The correct answer is: TS = CS - PS

The equation for calculating Target Speed (TS) when moving in the opposite direction with a front antenna is appropriately given by CS - PS. In this context, CS is the closing speed, which represents the speed of the target relative to the stationary point of reference (for example, the radar unit), and PS is the patrol speed, which is the speed at which the measurement device (like a police vehicle) is traveling. When the moving unit and the target are traveling in opposite directions, the closing speed is effectively the sum of both the patrol speed and the target speed since the objects are approaching each other. Thus, to find the Target Speed, you subtract the patrol speed from the closing speed, leading to the correct formula, TS = CS - PS. This formula accurately captures the dynamics of relative motion for radar implementations, where understanding the relationship between the speeds is crucial for correct speed enforcement and evaluation. The other choices do not accurately reflect this relationship. For example, the choice suggesting that TS equals PS plus CS would imply a different scenario which doesn’t apply here, as it incorrectly combines speeds instead of accounting for their directional effects.