High Resolution Distance Change-Phase Difference Measurement Technology

This paper presents a high-resolution linear phase comparison method, applied to the measurement of distance and distance change, it fully utilizes the signal periodicity and stability characteristics, greatly reduce the dependence on super-stable oscillator through the phase processing aims to achieve high-precision measurement, phase measurement accuracy can be superior to 0.1ps. Technological advances in this field will affect the development of high-precision space ranging, particularly, it plays an important role in the earth's gravity field measurements, microwave inter-satellite ranging, navigation and other related fields.Generally, time measurement has a higher accuracy than space measurement, spatial measurements achieved by measuring time can improve the measurement accuracy. The speed of electromagnetic signal traveling in free space is a natural constant, which is of high value and high stability. Therefore, utilizing the feature enables the mutual conversion between time measurement and spatial measurement. In this paper, high-precision measurement of distance changes is achieved through the measurement of the phase difference, which is obtained by the method of linear phase comparison of periodic frequency signals.We have produced a prototype to measure the distance, test results are given in this paper, which shows that distance measurement can reach millimeter magnitude.In this article the basic knowledge of group phase is introduced. By a relationship of two frequency signal periods, the phase comparison between a higher frequency signal and relative slow frequency signal will be completed. In this paper, the use of phase-interference phenomena in the measurement of special high-frequency and optical frequency is also discussed.