Book Description
The report reviews conceptual aspects and problems arising in a precise definition of reference frames for the purpose of geodesy and geodynamics. The concepts: physical, conventional, and average system are introduced. Inertial systems are discussed from the point of view of classical mechanics and of the theory of relativity. The concept of celestial pole, which plays a fundamental role in a precise definition of precession, nutation and polar motion, is reviewed in some detail. A section is devoted to tidal effects, which should be removed from the coordinates. Finally, various definitions of terrestrial reference systems are compared. (Author).