Scientists have paired NASA’s Cassini spacecraft with the National Science Foundation’s Very Long Baseline Array (VLBA) radio-telescope system to pinpoint the position of Saturn and its family of moons to within about 2 miles (4 kilometres) – http://astronomynow.com/2015/01/09/scientists-pinpoint-saturn-with-exquisite-accuracy/
More about Saturn here – http://saturn.jpl.nasa.gov/science/index.cfm?SciencePageID=51