Global Navigation Satellite System

Abstract

Abstract The Global Navigation Satellite System (Glonass) was designed to provide global real‐time determination of the position and velocity of an unlimited number of moving objects at any point on the Earth's surface, in the air, and in space. This system was developed in response to an order from the USSR (Russian Federation) Ministry of Defense. By instruction of the Russian Federation's President, the Glonass system was put into operation on 24 September, 1993. A 7 March, 1995 decree of the RF Government put the system at the disposal of the world community in standard mode intended for civil, commercial, and scientific use without a user fee. A RF Presidential decree of 18 February, 1999 designated the Glonass as a dual‐purpose (military and civilian) space navigation system. The system makes it possible to obtain highly accurate navigation location information with a maximum error less than or equal to 50–70 meters for position and 15 cm per second for velocity from any point on the globe or in near‐Earth space. Information is received in real time after a two to three minute pause, when the user's navigational system has just been turned on and continuously thereafter. At the same time, the system provides the capability to link the user's timescale with the State unified timescale with an error of no more than one microsecond. If the user's equipment can implement special methods for processing navigational information or differential operating modes are used, the accuracy with which the user's position is determined may be improved significantly. Tests have shown that the maximum error in such cases does not exceed a few meters. This article gives details on the concepts involved in positioning the system and the design of the satellite. Launch takes place at the Baykonur Spaceport. The Ground Control Complex tracks the satellite. The use of differential methods for navigation provides reliability and these methods are discussed. Because positioning is achieved through uninterrogated measurements of pseudorange and pseudovelocity, the number of users of the Glonass space navigational system is unlimited and may be as large as possible. Uses in space, air, ground, and the sea are detailed.