Path Difference and Its Difference Function

Abstract

This chapter is the most important one in this monograph. In this chapter, a detection method for phase change rate without phase ambiguity is presented. The results of this study lay a foundation for the realization of unambiguous phase difference localization. First, based on the functional relationship between the distance change rate and the phase shift change rate, the phase difference measurement method of the phase shift change rate is given through the difference approximation of the distance change rate. Then, the expression of phase difference change rate based on the multi-channel phase difference measurement is obtained by using the phase difference measurement of phase shift change rate and differential processing by phase differential rate of change. On this basis, by stripping the time difference term corresponding to the baseline length from the change rate of phase difference, a function representing the different characteristics of the number of wavelengths and the phase difference per unit wavelength length is extracted. The subsequent simulation results show that the variation of the difference function of path difference per unit wavelength length is very regular. The corresponding correction number can be determined directly by distinguishing the range of difference of phase difference, and the range is obtained by the actual measurement. A function expression can be obtained independent of the difference term of the integer of wavelengths as well as equivalent to the difference function of path difference. Finally, the problem of nonfuzzy phase difference measurement for path difference is briefly described. These research results undoubtedly provide a powerful technical support for the practical design of engineering related to phase measurement.