Meinberg microSync HR100/DC, Техническое описание

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6 GNSS Satellite Navigation
6 GNSS Satellite Navigation
The GNS satellite receiver clock is designed to provide users with a high-precision time & frequency reference.
This system, which can draw information from the satellites of the Russian GLONASS (GLObal NAvigation
Satellite System), American GPS (Global Positioning System), European Galileo, and Chinese BeiDou sys-
tems, is defined by its high precision and the ability to use it at any time, anywhere in the world.
These satellite-based systems are used for wireless tracking, navigation and time synchronization.
The use of a receiver for location tracking and time synchronization relies on the ability to measure the satellite-
to-receiver transmission delay as precisely as possible. It is necessary to have simultaneous reception from
four satellites so that the receiver can determine its relative spatial position in three dimensions (x, y, z) and
measure the deviation of its clock against the system clock. Monitoring stations around the planet track the
orbital trajectory of the satellites and detect deviations between the local atomic clocks and the system time.
The collected data is transmitted up to the satellites, which then send navigation data back to Earth.
The high-precision trajectory data of each satellite, known as the satellite’s ephemeris, is needed by the
receiver to continuously calculate the precise location of the satellites in space. A roughly defined ephemeridal
schedule based on empirical data, referred to as an almanac, is used by a receiver to identify which satellites
are visible above the horizon given a specific location and time. Each satellite transmits its own ephemeridal
schedule as well as the almanacs of all existing satellites.
GPS was installed by the United States Department of Defense (US DoD) and operates at two performance
levels: the Standard Positioning Service, or SPS, and the Precise Positioning Service, or PPS. The structure
of the messages transmitted by the SPS has been openly published and reception is provided for public use.
The timing and navigation data of the more precise PPS is encrypted and is thus only accessible to certain
(usually military) users.
GLONASS was originally developed by the Russian military for real-time navigation and ballistic missile
guidance systems. GLONASS satellites also send two types of signal: a Standard Precision Signal (SP) and
an encrypted High Precision Signal (HP).
BeiDou is a Chinese satellite navigation system. The second-generation system, officially referred to as the
BeiDou Navigation Satellite System (BDS) and also known as "COMPASS", consists of 35 satellites. BeiDou
entered service in December 2011 with ten satellites and was made available to users in the Asia-Pacific region.
The system was completed in June 2020 with the launch of the final satellite.
Galileo is an in-development global European satellite navigation and time reference system controlled by
a civilian authority (European Union Agency for the Space Programme, EUSPA). Its purpose is the worldwide
delivery of high-precision navigation data and is similarly structured to the American GPS, Russian GLONASS
and Chinese BeiDou systems. The main differences in the systems lie in their approaches to frequency usage
& modulation and the satellite constellations. A constellation of 30 satellites is planned to orbit the Earth over
three orbital planes, with nine satellites plus one spare planned for each orbital plane. At an orbital altitude
of 23,222 km above the Earth’s surface, the satellites require around 14 hours for a full orbit.
microSync Date: January 7, 2022 25