Research on Nonlinear Error Compensation Method for Interferometers Based on Tracker

A dynamic nonlinear error compensation method for the interferometers is proposed to meet the design demands of the tracker. It makes the system reach high precise measurement when the target is moving with high speed. With the passive compensation method of the optical path, part of the errors are eliminated. Thus, the periods of the signals could be counted accurately. A dynamic compensation method is proposed for the displacement in less than one period. By tracking the peak values and valley values of the interference signals in one cycle, the zero offsets error and unequal amplitude error can be compensated; then the quadrature phase shift error could be compensated by tracking the intersection of the two compensated signals. By tracking the signals and renewing the compensation parameters, the signals even with random nonlinear errors can get high-precision subdivision. Experiment results show that the system can get nanometer accuracy even the target is moving at high velocity. The system has better adaptability to different environment and anti-jamming capability.