  The arrival directions of TeV-PeV cosmic rays show weak but significant
anisotropies with relative intensities at the level of one per mille. Due to
the smallness of the anisotropies, quantitative studies require careful
disentanglement of detector effects from the observation. We discuss an
iterative maximum-likelihood reconstruction that simultaneously fits cosmic ray
anisotropies and detector acceptance. The method does not rely on detector
simulations and provides an optimal anisotropy reconstruction for ground-based
cosmic ray observatories located in the middle latitudes. It is particularly
well suited to the recovery of the dipole anisotropy, which is a crucial
observable for the study of cosmic ray diffusion in our Galaxy. We also provide
general analysis methods for recovering large- and small-scale anisotropies
that take into account systematic effects of the observation by ground-based
detectors.
