Enhancing the use of Galactic neutron stars as physical laboratories with precise astrometry

Neutron stars are among the most condense and magnetized objects in the universe. Hence, observations of neutron stars promise abundant scientific outputs. However, these studies are usually limited by the knowledge of the astrometric information (of the neutron stars), including the distances and proper motions. This thesis advances the forefront astrometric techniques (in particular the phase-referencing very long baseline interferometry techniques), utilizes them to determine precise astrometric parameters for various types of neutron stars, and discusses the scientific implications of these astrometric measurements.