2 research outputs found
Time and Reference Systems
Geodesy is the science of the measurement and
mapping of the Earth’s surface, and in this context
it is also the science that defines and realizes
coordinates and associated coordinate systems.
Geodesy thus is the foundation for all applications
of global navigation satellite system (GNSS). This
chapter presents the reference systems needed
to describe coordinates of points on the Earth’s
surface or in near space and to relate coordinate
systems among each other, as well as to some
absolute system, visually, a celestial system. The
topic is primarily one of geometry, but the geodynamics
of the Earth as a rotating body in the solar
system plays a fundamental role in defining and
transforming coordinate systems. Therefore, also
the fourth coordinate, time, is critical not only as
the independent variable in the dynamical theories,
but also as a parameter in modern geodetic
measurement systems. Instead of expounding the
theory of geodynamics and celestial mechanics,
it is sufficient for the purpose of this chapter to
describe the corresponding phenomena, textually,
analytically and illustratively, in order to give
a sense of the scope of the tasks involved in providing
accurate coordinate reference systems not
just to geodesists, but to all geoscientists