1. An eye tracking calibration system comprising: an eye tracking camera to track eye movement of a user in communication with a gaze estimation circuitry; a scene facing camera in communication with a scene analysis circuitry; an inertial sensor in communication with said scene analysis circuitry; said scene analysis circuitry detecting moving objects and estimating angular locations of said moving objects over a period of time, wherein said moving objects include two or more objects in a field of view surrounding a user; said gaze estimation circuitry receiving images from said eye tracking camera and estimating gaze angles of a user's eye, based on said images, over said period of time; an object trajectory matching circuitry computing, for each of said moving objects, a first distance measure between said object angular locations and said gaze angles, and further to decide on acceptance of said each moving object for use in calibration based on a comparison of said first distance measure to a distance measure threshold; and a calibration circuitry estimating an eye tracking calibration angle based on a minimization of a second distance measure, said second distance measure computed between said angular locations of said accepted moving objects and said gaze angles.