http://qz.com/847443/most-accurate-atomic-clock-on-earth/
Interesting article... the last couple paragraphs indicate that these clocks could eventually be used to create highly refined geoid models.
That's impressive sensitivity to gravity. Makes you wonder how the calibrate it to "true" time rate to begin with.
"clocks, when theyÛªre ticking in environments with a gravitational field, tick slower... This new set of two atomic clocks is so stable and precise, though, it can accurately detect these differences at a point just a centimeter higher from the earthÛªs surface."
On a related subject, absolute gravity meters, the developments in this field have direct impact in geodesy and geoid modeling. The latest and greatest is described above. Note that assessments of its accuracy are dependent on theoretical estimates. I basically watched its predecessor the FG5 being set up and turned on. Impressive piece of technology; in operation like watching paint dry (but takes a longer time).
In the thread on precise orbit file availability posted by Mr Frame, I posted an image showing IGS orbit product accuracies. Not we are talking about pico-second accuracies. Wow. 10^(-12) of a second.