A phase-measuring method to obtain distances applied to a robot positioning system

In this paper a method to measure the relative difference in the phase of two sin-carrier signals traveling from an emitter on board a robot towards two detectors is shown. It is applied to a local positioning system for autonomous robot guidance. The carrier signal is recovered from an ASK signal modulating the carrier with an MLS sequence for other purposes. The method provides a technique based on signal treatment showing high independency against changes in signals amplitude. The analog design developed as well as its features are shown and an alternative digital strategy is proposed as well.