Advanced telescopes and radars detect and track celestial bodies and determine their trajectory. We pretty much perfectly mapped the gravitational effects of all the large bodies in our solar system so a computer calculates future trajectory with the data observatories gather. Calculations are relatively simple even a phone app can do it with right data inputs.

But problem is the ones we cant see. Radar is useful in close range. And optical telescopes require astroids to pass in front of a light source ie sun

Problem with this question is motion in space is relativistic there could be 2 bodies of mass not have a motion regarding to each other. There is no object with mass doesnt move relatively to some other object. If your question is if there is a object that doesn't move relatively to space it self ,that is another can of worms because space it self is in motion (expansion)