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Changing Reference Frame

Changing Reference Frame. Frank Gielsdorf technet GmbH Berlin. Definition of Reference Frames. Situation in 1990. Were is the Problem?. Surveying and Navigation with GPS!. Example: German Railways. Positioning System for Trains. Required Positional Accuracy: 50cm. Necessary:

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Changing Reference Frame

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  1. Changing Reference Frame Frank Gielsdorf technet GmbH Berlin

  2. Definition of Reference Frames

  3. Situation in 1990

  4. Were is the Problem? Surveying and Navigation with GPS! Example: German Railways Positioning System for Trains Required Positional Accuracy: 50cm Necessary: Data base of the rail geometry with a unique spatial reference frame! Train with GPS Antenna

  5. Reference Frames Old: German Main Triangle Network (DHDN) datum point: TP Rauenberg reference ellipsoid: Bessel ( a = 6 377 397.155m , f = 1:299.1528 ) New: European Terrestrial Reference System 1989 (ETRS89) datum points: 23 laser- und VLBI positions in Europe reference ellipsoid: Geodetic Reference System 1980 (GRS80) ( a = 6 378 137m , f = 1:298.2572 )

  6. Projection UTM (Universal Transversal Mercator) Gauss-Krueger m = cosh(y/R) m = cosh(y/R)*0,9996

  7. 3D Datum Transformation (X, Y, h) DHDN / Gauss-Krueger Conversion Prerequisite: identical points (X, Y, Z) DHDN / geocentric Datum Transformation (adjustment problem) (X, Y, Z) ETRS89 / geocentric Conversion (X, Y, h) ETRS89 / UTM

  8. Adjustment Approach Functional Model

  9. Transformation Parameter NRW Quelle: Landesvermessungsamt NRW

  10. 2D Datum Transformation The analytical function of an complex number impart a conformal mapping. Special case: Helmert-Transformation

  11. Example North Rhine-Westphalia two meridional zones 155 TP 1. order degree 3 resp. 4

  12. Problem: Remaining Discrepancies • Remaining Discrepancies : • Residuals of coordinate observations • Causes: • Random deviations  adjustment calculation • Systematic influences  model extension • Solution: • Extension of the mapping rule

  13. Extension of the Mapping Rule Identical Identical Points Points DHDN ETRS89 Calculation of Transformation Parameters • Step • Transformation Transformation Parameters + Residuals New Points DHDN Transformation of New Points All Points in ETRS89 + Residuals Artificial Observations, Geometrical Constraints Adjustment 2. Step Neighborhood Fitting All Points in ETRS89

  14. Subproject from Hamburg Points: 6973 Reference Points: 36 Point Identities: 38 Triangle Sides: 20883

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