The GLObal Navigation Satellite System in Russia is an all-weather, high-precision satellite navigation and positioning system after the US GPS system. GLONASS is very similar to the US GPS in terms of working principle, system composition and service content.
The first satellite launch of the program was carried out in October 1982. In January 1996, Russia announced that GLONASS has full working capacity. The system currently has 16 satellites in orbit. Russia has started the modernization of GLONASS since 2001. Including: ground control part upgrade - improve time accuracy, insert time offset into the message; space part update plan - add new GLONASS satellite, develop new 18 GLONASS-M satellites, develop and launch third generation GLONASS-K satellite.
(1) Similarities between the Russian GLONASS system and the US GPS system
The number of satellites in the space of the two systems is the same, and the orbital structure is similar;
The frequency bands of the two systems are very close, and two signals can be received by a common antenna and a wideband preamplifier;
Both systems offer two levels of accuracy, high-precision services for special users, and low-precision services for both military and civilian services;
(2) Differences between the Russian GLONASS system and the US GPS system
The Russian GLONASS satellite transmits signals with frequency division multiple access at different frequencies, and the signals of the L2 frequency band are prepared by special codes that are not used by foreign users. US GPS satellites transmit signals in the code division multiple access format on the same frequency.
The broadcast ephemeris content of the two systems is different;
Russia GLONASS uses the Russian geocentric coordinate system, and the US GPS uses the world geodetic coordinate system;
The system time standard adopted by Russian GLONASS and US GPS is different.
