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Physical geodesy is the study of the physical properties of Earth's gravity and its potential field (the geopotential), with a view to their application in geodesy. Measurement procedure [ edit ]
Geodesy or geodetics [1] is the science of measuring and representing the geometry, gravity, and spatial orientation of the Earth in temporally varying 3D.It is called planetary geodesy when studying other astronomical bodies, such as planets or circumplanetary systems. [2]
Geodesy is an earth science and many consider the study of Earth's shape and gravity to be central to that science. It is also a discipline of applied mathematics . Geodynamical phenomena, including crustal motion, tides , and polar motion , can be studied by designing global and national control networks , applying space geodesy and ...
Techniques of satellite geodesy may be classified by instrument platform: A satellite may be observed with ground-based instruments (Earth-to-space-methods), carry an instrument or sensor as part of its payload to observe the Earth (space-to-Earth methods), or use its instruments to track or be tracked by another satellite (space-to-space methods).
Modern geodesy tends to retain the ellipsoid of revolution as a reference ellipsoid and treat triaxiality and pear shape as a part of the geoid figure: they are represented by the spherical harmonic coefficients , and , respectively, corresponding to degree and order numbers 2.2 for the triaxiality and 3.0 for the pear shape.
Geophysical surveys may use a great variety of sensing instruments, and data may be collected from above or below the Earth's surface or from aerial, orbital, or marine platforms. Geophysical surveys have many applications in geology, archaeology, mineral and energy exploration, oceanography, and engineering. Geophysical surveys are used in ...
Such instruments are capable of an accuracy of about 2 ppb or 0.002 mGal [1] and reference their measurement to atomic standards of length and time. Their primary use is for calibrating relative instruments, monitoring crustal deformation, and in geophysical studies requiring high accuracy and stability. However, absolute instruments are ...
A wooden tripod holding an optical level is set up firmly on the ground. Levelling or leveling (American English; see spelling differences) is a branch of surveying, the object of which is to establish or verify or measure the height of specified points relative to a datum.