Abstract: For uncontrolled projectile, such as cannonballs, rockets, etc, precession period is an important parameter of the trajectory characteristic. To obtain the precession period of projectile effectively, a precession period extraction method based on phase differential is introduced. Precession of projectile brings micro-Doppler modulation on echoes of continuous-wave radar, and its mathematic model indicates that the micro-velocity produced by precession changes with the law of sine, and the change rate of its phase is inversely proportional to precession period. The phase of the micro-velocity can be obtained by Hilbert transform, and then the precession period can be derived by the phase differential of the micro-velocity. The experimental results show that, for the micro-velocity signal which S/N is greater than 7 dB, precession period can be effectively extracted with the proposed method, and this method is more precise and smooth for actual measuring data. Key

Key words: ordnancescienceandtechnology, continuouswaveradar, precessionperiod, micro-Doppler, Hilberttransform