Velocity vector imaging by use of Linear-Period-Modulated signal.

Abstract

A linear-period-modulated (LPM) pulse is “Doppler tolerant” signal for correlation detector system, since its frequency altering property is invariant regardless of signal degradation due to Doppler distortion. A remarkable feature of this signal is no-error coupling on range velocity estimation when it is constructed symmetrically with respect to time reversal. Consequently, range and velocity of moving objects can be measured in good accuracy utilizing the double pulse structure of LPM signal.This paper describes a theory of range-velocity estimation using the LPM signal, extends it to a two-dimensional case with sensor array, and proposes a new method for velocity vector reconstruction of object motions. The validity of proposed system is confirmed by ultra-sound experiments in air. Reconstructed amplitudes indicate object motion information, and Moving Target Indication (MIT) is easily realized.