@jannem Both sampling across the entire rotation phase and multiple viewing angles (orientation of an #asteroid relative to Earth is never constant)! are critical.

#radar data in use here is all from #Arecibo - the LPI has most of it at https://www.lpi.usra.edu/resources/asteroids/asteroid/?asteroid_id=2010LE15 if you want to see. With these observations, one beams a radio signal to the asteroid and observes the echo returned. Interesting observed parameters include Doppler shift, polarization and echo power.