The measurement of the zero error of range in radar equipments

The paper briefly outlines the circuits used for measuring range in radar equipments. The errors encountered are considered and it is shown that these can all be eliminated or made very small, with the exception of the zero error which is inevitable. Three methods of measuring the zero error are described, particular attention being given to an electronic system which requires neither bulky apparatus nor the surveying of targets. The accuracy possible with this electronic calibrator is shown to depend on the ranging system of the particular radar equipment, but results within ten yards of the true value can usually be obtained without unduly complicating the measurements.