How might an enterprising spacer, mining the rings of Saturn, go about quickly measuring/estimating the velocity of and distance to a nearby moving object (asteroid, habitat, pirate, etc)? Bonus points for measuring acceleration.
The lower tech, the better! The Saturnians would rather a microprocessor not be in the loop at all. They are a tough bunch, and would prefer a more reliable method with less electronics/moving parts, even if it meant lots of training or practice. Human>mechanical>electronic.
Note that this is more for quick maneuvering, rather than plotting trajectories that will be accurate over long distances/times (though if the method works for those, that's great too). Distances are tens of kilometers (maybe 150km at the outside), and the relative velocities are on the order of 100km/hr.