Methods of obtaining picosecond time measurement accuracy in a space satellite optical location system

A problem of synchronization of time scales in remote objects (for example, in space satellites of Global Navigation Satellite System (GLONASS), located far away from each other) becomes especially important at present. Minimization of the time scales difference is necessary to provide accurate measurements of coordinates of the objects on the Earth surface. One of methods for solving a problem consists in measurement of the absolute time difference between each space satellite and the central synchronization station on the Earth using an optical location system. This paper presents basic methods for obtaining picosecond accuracy of time interval measurements in an optical location system designed for space satellites. The optical tract construction and electronic units circuitry is discussed. The most important error sources are shown and methods of their minimization are proposed. The basic results received during tests of the space terminal first sample are given in the conclusion.