We propose an automatic method to geo-register maritime video feeds to satellite images. The method first detects horizon during the day time and apex during the night time for similarity rectification. It then finds water pixels on both satellite images and camera views. Finally, geo-registration is obtained by searching the best orientation where the water masks are matched. The current state-art-of-state video surveillance system benefits with this method by providing situational awareness on maps with physical data including object size, location, and velocity in the world coordinates. Experimental results and applications such as cross camera tracking are demonstrated.