In a graphics processing and display system wherein the view point is controlled according to position and orientation of a view point reference with respect to a representation of the displayed graphics data determined by a view point reference coordinate sensing system comprising a source and a sensor, wherein the sensor has a fixed position and orientation with respect to said view point reference and the source has a fixed position and orientation with respect to the schematic representation, calibration of the system requires two ordered steps: view point reference-sensor calibration and source-representation calibration. View point reference-sensor calibration is performed by registering and processing four configurations of the sensor housing. Source-representation calibration is performed by storing and processing three positions of the sensor housing.