I recently converted some AutoCAD Map dwgs into shapefiles for ArcGIS 9.3.1, which is projected in NAD_1983_StatePlane_Utah_Central_FIPS_4302_Feet. Then I copied over GPS data from the Trimble GeoXT, which has ArcPad 7.1, onto my comp and reprojected it from WGC 84 to the Stae Plane projection to match it with the shapefiles from AutoCAD Map. Despite all of this, when I bring both on ArcMap, the shapefiles dont mesh together, instead the're far apart. Upon further examination, their coordinate values are very different from each other. So my question is which shapefile's coordinate sytem needs to be modified, the GPS or the AutoCAD? And would modifying the GPS's coordinate system effect the GPS data in terms of georeferencing? I welcome any tips and suggestions.