As concerns the use of RTCM observation correction data in GNSS positioning services, the coordinates are resulting within the ITRF or in a regional ITRF-realization (e.g. ETRF89 in Europe) as geocentric (x,y,z) or ellipsoidal (ϕ,λ ,h)... more
As concerns the use of RTCM observation correction data in GNSS positioning services, the coordinates are resulting within the ITRF or in a regional ITRF-realization (e.g. ETRF89 in Europe) as geocentric (x,y,z) or ellipsoidal (ϕ,λ ,h) coordinates. The users of GNSS services must however normally present their results in the coordinates of regional or local horizontal and vertical datum systems. Therefore, coordinate transformations are necessary.
Although, there are various software that perform least squares adjustment of horizontal geodetic network so as to determine the precision and accuracy of the network. But the theories and equations that were used to develop the programs... more
Although, there are various software that perform least squares adjustment of horizontal geodetic network so as to determine the precision and accuracy of the network. But the theories and equations that were used to develop the programs which the software are using are not quite understood by various user. This paper presents step by step procedures of horizontal geodetic network precision and accuracy determination using observation equation method of least squares technique. The detailed procedures are enumerated in sequential order for users understanding. The enumerated procedures are also demonstrated using a numeric example.
Abstract: Although, there are various software that perform least squares adjustment of horizontal geodetic network so as to determine the precision and accuracy of the network. But the theories and equations that were used to develop the... more
Abstract: Although, there are various software that perform least squares adjustment of horizontal geodetic network so as to determine the precision and accuracy of the network. But the theories and equations that were used to develop the programs which the software are using are not quite understood by various user. This paper presents step by step procedures of horizontal geodetic network precision and accuracy determination using observation equation method of least squares technique. The detailed procedures are enumerated in sequential order for users understanding. The enumerated procedures are also demonstrated using a numeric example.
Multiple regression equations (MREs) provide an empirical direct method of transforming coordinates between geodetic datums. Since they offer a means of modelling distortions, they are capable of a more accurate fit to datum-shift... more
Multiple regression equations (MREs) provide an empirical direct method of transforming coordinates between geodetic datums. Since they offer a means of modelling distortions, they are capable of a more accurate fit to datum-shift datasets than more basic direct methods. MRE models of datum shifts traditionally consist of polynomials based on relative latitude and longitude. However, the limited availability of low-power terms often leads to high-power terms being included, and these are a potential cause of instability. This paper introduces three variations based on simple partitions and 2 or 4 smoothly conjoined polynomials. The new types are North/South, East/West and Four-Quadrant. They increase the availability of low-order terms, enabling distortions to be modelled with fewer side effects. Case studies in Great Britain, Slovenia and Western Australia provide examples of partitioned MREs that are more accurate than conventional MREs with the same number of terms.
