Applications of soft computing methods in geodesy

Bu çalışmada Yapay Sinir Ağları (YSA) ve Bulanık Çıkarım Sistemleri (BÇS) jeodezinin en önemli problemlerinden bazılarının çözümü için kullanılmıştır. Bu problemler sırayla, Yer yuvarı gravite alanının modellenmesi ve de GPS/Nivelman ölçülerinden geoid yüzeyinin belirlenmesidir. Gravite alanı modellemesi için GRACE (Gravity Recovery And Climate Experiment) uydu gravimetre verileri,GPS/Nivelman geoidi için ise İzmir metropolitan GPS nirengi ağında yapılan GPS ve nivelman ölçülerinden türetilmiş geoid yükseklikleri bilinen kontrol noktaları kullanılmıştır. Her iki uygulama sonucunda esnek hesaplama yöntemlerinin, özellikle girdi-çıktı sistemleri şeklinde tanımlanan jeodezik problemlerin çözümü için uygun yöntemler olduğu sonucuna varılmıştır.    Anahtar Kelimeler: BÇS, geoid,GRACE, gravite alanı,YSA.Soft computing methods such as artificial neural networks (ANN) and fuzzy inference systems (FIS) have been widely used methods in various science and engineering fields. As the backgrounds of these methods are not very old, they have shown a rapid development with the improvements in computer systems and computation techniques. Their use in geodesy is quite new. In this study, both ANN and FIS have been used to solve the some of the major problems in geodesy. These problems are modelling of Earth’s gravity field and the determination of geoid surface from GPS/Levelling. For gravity field modeling, GRACE (Gravity recovery And Climate Experiment) satellite gravimetry data, and for GPS/Levelling geoid control points with known geoid heights derived from GPS and levelling measurements in İzmir metropolitan GPS network were used The results from the soft methods used in computations were also compared with those from the conventional methods in terms of model quality measures like root mean square (RMS) error, mean error,  mean absolute error, error range, correlation coefficient. Both applications’ results have concluded that soft computing methods are appropriate methods for the solution of geodetic problems especially which can be defined as input-output systems and should be considered for the solution of different other problems in geodetic science.        Keywords: ANN, FIS, geoid,GRACE, gravity fiel

Global Monthly TWSA grids at 1-deg by 1-deg spatial resolution

The data includes global monthly TWSA at 1-deg by 1-deg spatial resolution from January 1994 to January 2021 with no gap

Monthly Spherical Harmonic Models up to d/o 200

The data set is the spherical harmonic model coefficients for monthly mass changes up to d/o 200 from January 1994 to January 2021 with no gaps