On protecting the planet against cosmic attack: Ultrafast real-time estimate of the asteroid׳s radial velocity

•A new method for line-of-sight velocity estimation of a high-speed NEO is suggested.•It appears preferable for use in orbital weapon systems of threat response.•The method is based on use of fractional, one-half order derivative of a Doppler signal.•The method allows an assessment of the mean frequency without spectral analysis.•The wait time can be shortened by orders of magnitude compared to spectral processing.

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 the 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.