Satellite communications have received an increasing attention in the last three decades because of their potential service to rural areas that cannot economically be incorporated into terrestrial systems. For satellite communications, M-ary Phase Shift Keying (MPSK) schemes are widely used because they offer a good trade-off between power and bandwidth. in this paper an algorithm for automatic real time classification of MPSK with M= 2, 4, and 8 in presence of satellite channel impairments is introduced. A combination of digital signal processing and pattern recognition methods is used for solving the recognition problem. The developed algorithm has been tested by computer simulations and has proven to be reliable and robust against the expected channel impairments (interference) such as noise, fading, shadowing, and transponder non-linearity. It is found that all digital modulation types of interest have been correctly classified with a success rate > 94 % at signal-to-interference ratio, SIR, of 10 dB.