RAF Calibration Cart / Transfer Standard; Empirically Derived Corrections (PCORS) to adjust for location and airspeed effects. Calibrations are performed regularly and data processing incorporates the latest calibration for each project. In addition, tests to determine the accuracy of the “static button” pressure sources on the GV have been used to determine corrections that are dependent on angle of attack, pressure, and dynamic pressure. These corrections have been determined in three ways: (1) via tests using a trailing-cone pressure port; (2) via comparisons to the standard avionics pressure measurement on the aircraft (which has been demonstrated to meet Reduced Vertical Separation Minimum (RVSM) standards; and (3) measurements from a laser air motion sensing system, which is used to calibrate dynamic pressure and hence, under the assumption that static pressure is measured with high accuracy, total pressure. Overall accuracy is estimated at < 0.3 mb.