  A new method for the line-of-sight velocity estimation of a high-speed
near-Earth object (asteroid, meteorite) is suggested. The method is based on
use of fractional, one-half order derivative of a Doppler signal. The algorithm
suggested is much simpler and more economical than the classical one, and it
appears preferable for use in orbital weapon systems of threat response.
Application of fractional differentiation to quick evaluation of mean frequency
location of the reflected Doppler signal is justified. The method allows an
assessment of the mean frequency in the time domain without spectral analysis.
An algorithm structure for the real-time estimation is presented. The velocity
resolution estimates are made for typical asteroids in the X-band. It is shown
that the wait time can be shortened by orders of magnitude compared with
similar value in the case of a standard spectral processing.
