Doppler-effect experiments and Lorentz symmetry

Within the context of the Lorentz-violating standard-model extension, I present preliminary results of a study of precision Doppler-effect experiments. While other types of experiments, such as clock-comparison and spin-torsion experiments, already provide sensitive tests of Lorentz symmetry in atomic systems, they do not cover all possible types of Lorentz-violating interactions. Doppler-effect experiments provide tests of some sectors of the standard-model extension that are unprobed by other classes of experiments. I present analysis of already-completed Doppler experiments from the Heidelberg Storage Ring.