We spent a week out at Columbia Glacier running a radar interferometry system. As the glacier moves, the phase of the reflected radar wave shifts. Unwrapping the interference pattern between subsequent returns allows you to detect changes in range down to a few millimeters, which in turn allows velocities to be calculated over short time periods. Ryan Cassotto was the radar monkey. Bob-o and Adam Clark were the chief battery schleppers. I didn't actually do much.