EVOLUTIONARY SPECTRA OF BACKSCATTERING WAVE IN MOVING MEDIUM

In this paper,we discuss the backscattering wave of sonar,radar and sodar in moving medium,which is anon-stationary stochastic process even if its energy attenuation is compensated.The evolutionary spectra are agood approach to describe it,both the non-stationary factor A(ω) and the characteristic width Baresignificant.When the time interval corresponding to the volume element of the scatterers is smaller than B,we can suppose that the power spectrum displays a single hump characteristic,and when it is larger than B,we may use the power spectrum which displays a bi-hump characteristics.The transmitted signal which hasslow varing ambiguity function can reduce the effect of A,(ω).