TY - JOUR
T1 - Testing Stokes-Helmert geoid model computation on a synthetic gravity field
T2 - experiences and shortcomings
AU - Vanicek, Petr
AU - Kingdon, Robert
AU - Kuhn, Michael
AU - Ellmann, Artu
AU - Featherstone, William
AU - Santos, Marcelo C.
AU - Martinec, Zdenek
AU - Hirt, Christian
AU - Avalos-Naranjo, David
PY - 2013/7
Y1 - 2013/7
N2 - We report on testing the UNB (University of New Brunswick) software suite for accurate regional geoid model determination by use of Stokes-Helmert's method against an Australian Synthetic Field (ASF) as "ground truth". This testing has taken several years and has led to discoveries of several significant errors (larger than 5mm in the resulting geoid models) both in the UNB software as well as the ASF. It was our hope that, after correcting the errors in UNB software, we would be able to come up with some definite numbers as far as the achievable accuracy for a geoid model computed by the UNB software. Unfortunately, it turned out that the ASF contained errors, some of as yet unknown origin, that will have to be removed before that ultimate goal can be reached. Regardless, the testing has taught us some valuable lessons, which we describe in this paper. As matters stand now, it seems that given errorless gravity data on 1' by 1' grid, a digital elevation model of a reasonable accuracy and no topographical density variations, the Stokes-Helmert approach as realised in the UNB software suite is capable of delivering an accuracy of the geoid model of no constant bias, standard deviation of about 25 mm and a maximum range of about 200 mm. We note that the UNB software suite does not use any corrective measures, such as biases and tilts or surface fitting, so the resulting errors reflect only the errors in modelling the geoid.
AB - We report on testing the UNB (University of New Brunswick) software suite for accurate regional geoid model determination by use of Stokes-Helmert's method against an Australian Synthetic Field (ASF) as "ground truth". This testing has taken several years and has led to discoveries of several significant errors (larger than 5mm in the resulting geoid models) both in the UNB software as well as the ASF. It was our hope that, after correcting the errors in UNB software, we would be able to come up with some definite numbers as far as the achievable accuracy for a geoid model computed by the UNB software. Unfortunately, it turned out that the ASF contained errors, some of as yet unknown origin, that will have to be removed before that ultimate goal can be reached. Regardless, the testing has taught us some valuable lessons, which we describe in this paper. As matters stand now, it seems that given errorless gravity data on 1' by 1' grid, a digital elevation model of a reasonable accuracy and no topographical density variations, the Stokes-Helmert approach as realised in the UNB software suite is capable of delivering an accuracy of the geoid model of no constant bias, standard deviation of about 25 mm and a maximum range of about 200 mm. We note that the UNB software suite does not use any corrective measures, such as biases and tilts or surface fitting, so the resulting errors reflect only the errors in modelling the geoid.
KW - synthetic gravity models
KW - geoid
KW - topographic effects
KW - Stokes-Helmert method
KW - DOWNWARD CONTINUATION
KW - ORTHOMETRIC HEIGHTS
KW - PHYSICAL GEODESY
KW - INTEGRATION
KW - AUSTRALIA
KW - EARTH
KW - FORMULA
U2 - 10.1007/s11200-012-0270-z
DO - 10.1007/s11200-012-0270-z
M3 - Article
VL - 57
SP - 369
EP - 400
JO - Studia Geophysica et Geodaetica
JF - Studia Geophysica et Geodaetica
SN - 0039-3169
IS - 3
ER -