Radar astronomy has provided detailed information on the orbits, sizes, shapes, rotation states, and composition of many asteroids. To improve the capabilities of asteroid radar observations, I have developed the technique of radar speckle tracking. The echoes from different points on the surface of a radar target interfere with each other, producing a pattern of bright and dark speckles across the surface of the Earth. Using radio astronomy techniques, I track the motion of speckles between several ground stations during a radar experiment to accurately determine the rotation state of the target. Speckle tracking is a powerful tool both to determine the orbital evolution of near-Earth asteroids, particularly potential Earth impactors, and to survey the overall physical properties of the asteroid population.
In addition, I have studied applying the techniques of adaptive optics and radio interferometry to asteroid science. These will become more useful with the next generation of asteroid-detecting surveys and the construction of large sub-millimeter interferometers. Interferometry in particular will soon be able to survey the entire asteroid belt.