collision-avoidance system for the cockpits of all aircraft. The system will receive real-time radar data and need to continuously calculate if a collision is likely, and give several different levels of warning. The system will need to deal with the entire range of fixed- and rotary-wing aircraft.
We are assuming that the planes are not already within each others collision radius
We are assuming that collisions that began in the past are irrelevant regardless of whether or not they have ended yet, see 1 for why
We assume that all planes that are moving at the same velocity (same speed and heading) are misses. Because any time that they would be considered hits violates condition 1