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Physics of the Globe
Published in Aurèle Parriaux, Geology, 2018
This type of reference makes it possible to assign a latitude L (in degrees), a theoretical or normal gravity (g0) that includes the effect of centrifugal force (international gravity formula, IUGG, 1980): () g0(L)=9.780327(1+0.0053024sin2L−0.0000058sin22L)m/s2
Georeferencing Component of LiDAR Systems
Published in Jie Shan, Charles K. Toth, Topographic Laser Ranging and Scanning, 2018
The gravity vector in the local-level frame, g ℓ, is expressed as the normal gravity at the geodetic latitude φ, and ellipsoidal height h (El-Sheimy, 2000) () gℓ=[00g]T,g=a1(1+a2sin2φ+a3sin4φ)+(a4+a5sin2φ)h+a6h2
Physics of the Globe
Published in Aurèle Parriaux, Geology, 2018
This type of reference makes it possible to assign a latitude L (in degrees), a theoretical or normal gravity (g0) that includes the effect of centrifugal force (international gravity formula, IUGG, 1980): () g0(L)=9.780327(1+0.0053024sin2L−0.0000058sin22L)m/s2
Description and release of Australian gravity field model testing data
Published in Australian Journal of Earth Sciences, 2018
W. E. Featherstone, N. J. Brown, J. C. McCubbine, M. S. Filmer
The levelling data provided for Australia therefore come from two LSAs. Source 1 is the ‘official’ published AHD heights of the benchmarks from the 1971 LSA (Roelse, Granger, & Graham, 1971), together with an estimate of their uncertainty (at one sigma), which has not previously been publicly available. Source 2 is a LSA of the Australian National Levelling Network (ANLN) that is constrained at 32 tide gauges to mean sea-level values that are corrected for the MDT using the Australian Commonwealth Scientific and Industrial Research Organisation Atlas of Regional Seas 2009 (CARS2009; Dunn & Ridgway, 2002; Ridgway, Dunn, & Wilkin, 2002). The use of MDT values from CARS2009 at the tide gauges results in the adjusted levelling network being more closely aligned to the geoid (Featherstone et al., 2017; Filmer, Featherstone, & Claessens, 2014). The rationale for the latter LSA is that there are remaining distortions in the AHD that cannot be removed by a tilted plane alone (Featherstone & Filmer, 2012) owing to uncorrected gross, random and systemic levelling errors (e.g. Filmer & Featherstone, 2009, 2011; Morgan, 1992; Roelse et al., 1971). In addition, the AHD uses normal-orthometric heights through the use of the Rapp (1961) normal-orthometric correction using normal gravity from the Geodetic Reference System 1967 (GRS67; International Association of Geodesy, 1971). The CARS2009-constrained LSA of the ANLN provides normal heights, using gravity values from EGM2008 through the application of the normal correction and GRS80 normal gravity (Moritz, 1980), as described in Filmer, Featherstone, and Kuhn (2010).