To calculate a lead angle for a moving target, given target course and speed and own ship speed, which method is used?

• A. Relative motion: compute closing velocity, target motion, and apply a lead angle based on intercept geometry and projectile velocity
• B. Use target course alone
• C. Use own speed alone
• D. Guess based on past engagements

Answer: (A)

Hit a moving target by treating the engagement as an intercept problem using relative motion. You bring together the target’s course and speed, your own ship speed, and the projectile’s velocity to predict where the target will be when the round arrives. By analyzing the relative motion, you determine the closing velocity and the target’s future position, then choose the aim point ahead of the target—the lead angle—that aligns the projectile’s travel time with the target’s displacement. This requires both sets of motion data and the projectile speed; using only the target’s course, or only your own speed, or guessing from past engagements, won’t yield the correct lead.