Patent ID: 6988566

Claim:
An acoustic position measurement system comprising: an acoustic transmitter operable to transmit a sound wave into an underground well bore in a target formation, the sound wave configured to reflect from a boundary formation proximate the target formation; an acoustic receiver operable to receive a reflected sound wave, the reflected sound wave comprising a reflection of the sound wave from the boundary formation; an electronics portion electrically coupled to the acoustic receiver, the electronics portion operable to: process the reflected sound wave; and produce, based upon a characteristic of the reflected sound wave, data output indicative of a position of the acoustic position measurement system in the target formation; and a plurality of acoustic receivers operable to receive a plurality of reflected sound waves, wherein the plurality of acoustic receivers are coupled to the electronics portion, and wherein the electronics portion is further operable to: shift the phase of the primary sinusoidal component of at least one of the reflected sound waves to bring the primary sinusoidal component of each reflected sound wave into alignment with respect to the primary sinusoidal component of the other reflected sound waves; and produce the data output based on the reflected sound waves.