What is the radar range formula for target range, R?

• A. S×T
• B. S−T
• C. (S+T)/2
• D. (S)(T)/2

Answer: (D)

The essential idea is that range comes from distance = speed × time, but radar measures the round-trip time of the pulse. The signal travels to the target and back, so the distance the wave covers during the round trip is speed × round-trip time. That round-trip distance is twice the one-way range, so the actual target range is half of that: R = (S × T) / 2. Here S is the propagation speed (about 3×10^8 m/s in air) and T is the measured round-trip time. This is why multiplying speed by time gives a distance, and dividing by 2 yields the one-way range.