Because a monopulse ratio is distorted and a Doppler mismatch may occur

the performance of the existing space-time adaptive monopulse angle estimation is degraded severely.This paper gives mathematical analysis of the failure mechanism of the conventional space-time adaptive monopulse method.In view of the space-time coupling characteristic of airborne radar clutter

this paper expands a constraint for difference beam to a space-time domain.A novel space-time adaptive monopulse angle estimation approach based on the space-time joint constraint is proposed

and a monopulse curve is extended to a monopulse surface.The accuracy and robustness of angle estimation are improved by the space-time joint constraint.Simulation results verify the validity of the novel method.