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Abstract

IAG Commission 1 Working Group 1.3.1 in association with the Open Geospatial Consortium (OGC) have developed a deformation model functional model (DMFM) and an associated Geodetic Grid Exchange Format (GGXF) for quantifying and disseminating deformation information for use in time-dependent reference frame transformations. The purpose of the DMFM is to provide a framework through which producers and users of deformation models can describe crustal displacement and velocity data using robust grid formats such as GGXF. Using the DMFM and GGXF combined, positional displacements can be readily applied in point motion coordinate operations. This approach is essential in deforming zones where conformal time-dependent transformation approaches do not adequately handle crustal deformation. The presentation describes how the DMFM can be applied in typical use cases. These include: transforming GNSS PPP positions (e.g. in an IGS20 frame) to a national geodetic datum in a deforming zone and transformations between reference frames across earthquake events resulting in significant coseismic and postseismic crustal displacement. The DMFM and associated GGXF provide a framework for developers of geodetic software such as those used in GIS, GNSS processing and positioning to better handle complex deformation.