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.
Keywords: Doppler shift, Passive localization, Path difference, Phase ambiguity, Phase difference rate, Phase interference.