ABSTRACT
The resolution capability of the pulse echo ranging technology is absolutely restricted by the duration of the echo signal. In view of this situation, imitating the principle of Michelson interferometer, author puts forward seismic interferential Ranging method which is independent of the signal waveform and can built with the seismic wave length as measure.
At the beginning in the article, the foundamental principle of the interferential Ranging is expound with simple condition, then it is extended to general conditions and gives out final result. On the basis of this theory the mode tests are successfully completed with computer simulating and some practical data have been processed with good result.
