Abstract: A novel geometric parameter measuring principle for workpiece with big and complicated shape and thin wall which is very difficult to be measured, such as a missile radome, is put forward and the instrument based on the principle is developed and manufactured. The hardware system and software systems for the measuring controlling system of the instrument are designed. At first, the principle and the composition of the instrument are presented. The methods to evaluate the errors and to process the data measured are discussed and the measuring results from practical examples are given out. The application results show that the instrument can perfectly satisfy the requirement for automatic testing the radome precisely, rapidly and economically.

Key words: Geometric parameter, Measuring, Radome