The micro-motion of radar targets commonly mixes with bulk translation. In order to extract the micro-Doppler signature of moving targets during a long observation time, it is necessary to perform coherent preprocessing on the echo to compensate the bulk translation. This paper first derives the narrowband echo model for high-speed targets with precession and gives a coherent preprocessing algorithm based on the echo model. Then the micro-Doppler signature is analyzed by joint time frequency transform and the micro-motion period is estimated by a method based on inverse radon transform. Finally, the proposed algorithm is verified with the simulation echo of a cone with precession.