GLONASS system is controlled by the Russian government through the Russian Space Forces. This system will provide community benefits for civil users though a variety of applications.
GLONASS system has two types of navigation signals: standard navigation signal, low SP signal precision and high SP signal precision. Positioning systems and time with the SP signal is available to all civilians across the world continuously and provides a positioning accuracy of 57 – 70 m horizontal, and positioning accuracy of 70 m vertical.
These characteristics can be significantly improved by using differential mode navigation and special measuring methods. To obtain a 3D positioning, velocity and time determination system, users using radio signals of GLONASS navigation satellites that are transmitted continuously.
GLONASS receivers automatically record GLONASS signals from at least four satellites and measures the pseudo – distance to them. They select and process messages simultaneously navigational satellites. Each GLONASS satellite moves in an orbit at a height of 19.100 km and each satellite through full orbit in approximately 11 hours and 15 minutes.
A feature of the GLONASS constellation is that a satellite will occupy the same position after eight days. How each orbital contains eight satellites, there is a repetition of the same sidereal after a day because that position will be occupied by another satellite. This is different from GPS (visit website http://gps-phonetracker.net/) constellation where these is an identical repetition after a sidereal day.
GLONASS satellites are equipped with cesium clocks to measure time with high precision. AS is well known, the fundamental time scale for all systems on earth is TAI. This time is the result of analysis by BIH from Paris.
The TAI time has one drawback: the rotation of the earth around the sun is slowed by about a second per year which will ultimatelylead to a lack of synchronization with the solar day time TAI. This problem was overcome by the introduction of UTC time with the same unit of measure as TAI but accept a second leap year which usually happens in late June or December each year.
UTC time is kept by VNIIFTRI (Main metrological Russian Center of Time and Frequency Service) located at Mendeleevo, Moscow region. When UTC is incremented by one second increments and its GLONASS system he so there is time difference in seconds between GLONASS time and UTC. GLONASS constellation is managed on ground by GCS.
It is composed of System Control Centre and several tracking stations that are located on Russian territory. CTS Stations are following the visible satellites and accumulate date on their signal. Information from CTS is processed SCC station to determine satellite time, precise orbits and thus correct navigation message of each satellite. These data are transmitted via CTS satellite that are used to transmit control information.
Almanac keeps information about all GLONASS satellites and orbital elements include kepleriene, and the time lag for each of the GLONASS system clock and data about the health of the satellite. A satellite is launched at a speed of 30,000 km / h. If no external force would not influence it would travel in a straight line in space. Just can not do that because our planet’s gravity attracts, so it is drawn into a circular path around the Earth. Then, the satellite orbits.