Process and system for measuring the distance of a moving body from a fixed part

摘要

A process for measuring the distance of a moving body (12) from a fixed part (10), comprising the steps of: generating a first alternating signal (r(t)) having a frequency (f) within the radio-wave range or of elastic-wave range; emitting the first signal from the fixed part towards the moving body (12) ; receiving the first signal (r(t)) on the moving body (12) and generating there a second signal (s(t)) having a frequency (n x f) and an initial phase (ϕ1) equal to the phase (2 pi ft1 + ϕ0) at the instant (t1) in which it is received by the moving body (12); generating, on the fixed part, a third signal (u(t)) having a frequency (n x f) and an initial phase (ϕ0) equal to the initial phase of the first signal (r(t)) ; and determining the variation in distance of the moving body (12) from the sum of (s(t)) and (u(t)).