On the Kinematics of Vehicles Relevant to Conflict Detection and Resolution

Figure 5

For vehicles moving with constant velocities if the relative velocity makes an obtuse angle with the relative initial positions then (case (a)) the trajectories converge, and the time of closest approach is in the future . If the relative velocity makes an acute angle with the relative initial position , the trajectories diverge, and the closest approach was in the past .

(a)

(b)