488HS4 GPS & GLONASS time code receiver systems

• Wharton 488HS4-GPS and 488HS4-GLONASS receivers provide a precise coded time signal locked to the transmissions of the respective satellite chain.
• These receivers are designed to provide simple and very accurate time synchronisation for Wharton 5200 series Ethernet Time Servers or individual Wharton 4000 series Digital Clocks and Wharton 4700 World Time Zone Clocks.
• The 488HS4-GPS and 488HS4-GLONASS receivers have a small, rugged IP65 rated weatherproof case housing both the active antenna module and the receiver/decoder interface.

What is GPS?

• The Global Positioning System is a satellite-based navigation system developed by the U.S. Department of Defence (USDOD) for military use which was made available for civilian applications in 1983.
• The satellites orbit the earth in six, nearly circular, orbits at an altitude of 20,200km (10,000 nautical miles) with four operational satellites plus a spare in each.
• Each orbital plane is equally spaced about the equator and inclined at 64.8 degrees. The satellites transmit highly accurate, real-time, worldwide navigation information at a frequency of 1598-1609 MHz.

What is GLONASS?

• The GLONASS navigation system was developed by the Russian government, initially for military use and now available for unlimited commercial access.
• GLONASS has satellites in three orbits at an altitude of 19,100km (10,313 nautical miles), transmitting precise time and navigation information at a frequency of 1598-1609 MHz

How GPS is used to calculate accurate local time

• Each satellite continuously transmits a unique code message format which includes precise orbital data and highly accurate time information derived from an atomic clock.
• The Wharton 488HS-GPS or 488HS-GLONASS receiver simultaneously receives the signals from several satellites.
• The receiver calculates the exact position of each of the satellites and by triangulation, the receiver's geographical location together with a precise local time.

Installation

• The connection between the 488HS4-GPS or 488HS4-GLONASS synchronisation system and the 5200 series network time server is by a four-core screened twisted pair cable up to 200m long. This cable also provides power to the 488HS4 receiver/decoder module.
• The gain pattern of the antenna has full upper hemispherical coverage with the gain diminishing at low elevations. This cross-section is consistent through 360 degrees with a symmetrical spheroid surface 3-dimensional gain pattern.
• The 488HS4 series receiver system should be mounted horizontally with a clear view of 75% of the sky. If the sky view is less than 75%, the interval between ‘switch-on’ and system time synchronisation will increase significantly.
• We include a post mounting clamp for fixing the antenna to be attached to a suitable horizontal or vertical post of up to 32mm diameter. The antenna may be mounted on the roof of a building or under a suitable skylight.
• We include a 25m long, 4 core 0.5mm² (7/0.2mm) screened cable for connecting the receiver to the 5000 series time server or master clock. You can specify a 100m cable at extra with the code 488HS4-100M.
• To ensure ease of operation and to remove the possibility of operator error, the 488HS4 system is designed to self initialise without the necessity of operator data input. When powered-up the receiver will automatically begin to search the sky for all available satellites. After the acquisition of three satellites, a precise date and time calculation is made from the satellite data transmissions.
• When the 5200 series network time server is synchronised with the GPS or GLONASS receiver/decoder module all transmitted signals are accurate to within +/- 50uS.