Method of dynamic geometric parameter measurement by laser tracking system

The main methods for measuring geometric parameters are used to be static or quasi-static measurement. Recently, however, dynamic geometric parameters measurement has been becoming increasingly important and turning into a new field in metrology. The laser tracking system for measuring dynamic geometric parameters of moving targets employs laser dynamic aiming technique, laser interferometry and control technique of precision instruments. The moving target is tracked and its geometric parameters are measured in real time. The measurement range is one to ten meters and the accuracy is fifty microns per meter. It is a novel computer integral system with both measuring and controlling capacity. This paper present the characteristic and concept of dynamic geometric parameters measurements and puts forward the cardinal measuring principles and methods of the laser tracking system. This paper also gives a more detailed discussion about the key techniques for this system, which are different from the static measurement, such as the self- calibration principle, the redundancy design principle, the fault-tolerant design principle, the virtual coordinate system establishment principle. We will also discuss the developing trend of laser tracking system for measuring dynamic geometric parameters at the end of the paper.