In this talk, I will discuss how recent advancements in high precision astrometry have revolutionized our ability to study the dynamics of satellite galaxies and improve our understanding of the Local Group's history. I will demonstrate that astrometric measurements are particularly powerful when combined with high resolution cosmological simulations because they can be used to constrain fundamental host galaxy properties, such as halo mass, and the orbital histories of individual satellite galaxies. Finally, I will highlight the Andromeda (M31) system where we are just beginning to explore the details and dynamics of halo substructures. Upcoming telescopes like JWST will be key to increasing our knowledge of M31 satellite galaxies and their interaction histories.