Fix the discontinuous velocity of multiple tracking from slewing. This problems comes from the slewing algorithm that assumes the initial and final velocities to be zero. The velocity of tracking target is added as a superposition method.

In the following figures, there are two targets. The first target is at 1.2 deg with velocity = 0.01 deg/sec. The second target is at 3 deg with velocity = -0.01 deg/sec. There is a dip of velocity transition here (to 2nd target):

This velocity transitions from 0.01 deg/sec to -0.01 deg/sec happens in 0.005 seconds, which is 20 steps in 4000 Hz. We can see the acceleration > 0 for the new slew. Therefore, this transition does not make the physical sense at all.