Mounting GPS antenna Standard GPS antenna for A & B channels The std. GPS satellite time receiver has been designed to provide extremely precise time (aprox. 50nS). The NTS-x000 can be also equipped with L1/L2 double frequency GPS receiver (20nS). High precision time is available 24 hours a day around the whole world. The Global Positioning System (GPS) is a satellite-based radio-positioning, navigation, and time-transfer system. The source of time is based on cesium atomic clocks (TAI). Time is represented rescaled to UTC time scale with automatic leap second support. Einstein's general relativity plays role in GPS time. The GPS satellite clocks are moving at 14,000 km/hr in orbits that circle the Earth twice per day, much faster than clocks on the surface of the Earth, and Einstein's theory of special relativity says that rapidly moving clocks tick more slowly, by about 7 microseconds (millionths of a second) per day. Also, the orbiting GPS clocks are 20,000 km above the Earth, and experience gravity that is four times weaker than that on the ground. Einstein's general relativity theory says that gravity curves space and time, resulting in a tendency for the orbiting clocks to tick slightly faster, by about 45 microseconds per day. The net result is that time on a GPS satellite clock advances faster than a clock on the ground by about 38 microseconds per day. .
The GPS satellites are not stationary but circle round the globe in a period of approx. about 12 hours. They can only be received if there is no building in the line of sight from the antenna to the satellite, so the antenna unit must be installed in a location from which as much of the sky as possible can be seen. The hardware of the GPS antenna contains in one box. In a box are placed GPS receiver, frequency converter and basic over-voltage protection. Box is water resistant (IP67) therefore it should stay over water level during rain.
The metal handler should be mounted on top of building and grouded. Please select location of GPS antenna on way it work will be not disturbed by any other radio-transmitter or antennas. We advice to keep min. distance of 5m from other electronic devices as GSM/UMTS trans-receivers, radars, telecoms equipment, air conditions etc. Your GPS box antenna should be mounted solid to avoid strong winds and other bad weather conditions. Water, salt and snow conditions are acceptable under condition the box remind over water level (IP67). For surge and over voltage
protection please refer to
NTS-protect*** /available separately/.
This module includes special lightning protectors
preventing NTS-4000 server from direct and indirect
effects of atmospheric discharges and related over
voltage defects. The construction of NTS-protect is
based upon the rule of voltage compensation in
accordance with PN – IEC 61024-1 standard
regulations. It stipulates upholding safe levels of
over voltage that will not damage the insulation in all
protected electrical circuits of the NTS-xxxx server.
For connecting antenna (GPS alone or GPS+DCF77) box we recommend usage of UTP or STP cat. 5 cables (for external environment. use) with standard RJ-45 connector termination (both sides) with standard T568B conductors assignment. Cable should be leaded into antenna box through cable gland. Please use standard Ethernet cramping tooling (not included to NTS-xxxx set) to mount antenna cable connection.
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