Precise Time Synchronization Using Microcontroller Controlled GPS Based Clock Device

Abstract

A Master clock device is a precision clock device that provides timing signals to synchronize slave clocks as part of a clock network. This device normally takes one or more precise timing reference signals as inputs, then convert and distribute those timing references to other devices so the slave clocks are as accurate as the master clock. Typically, GPS satellite signals are utilized for synchronization to ensure accurate time. GPS satellites travel in nearly circular orbits every 12 hours at an altitude of 20,200km. The exact position of each satellite can be determined at all times. Each satellite continuously transmits a unique code sequence, derived from atomic clocks, which is tracked by the GPS receiver. The transmitted information includes current orbital data for each satellite. The GPS receiver is able to identify each satellite by its code and is able to calculate the satellite's exact position in space. The GPS receiver uses the calculated information to determine its distance from several satellites. The receiver then uses a process called triangulation to compute its own position together with a precise UTC time. GPS Master Clock indicate time in either UTC format or Local format. The Device is available with one 1PPS Port, two Ethernet port and two IRIGB (AM/PWM) outputs. Optional outputs include one IRIG-B AM/PWM, 1PPS and one Ethernet output (NTP). The Optimized Receiver/Antenna system employed in the Device provides time information from the GPS satellite constellation. Dynamic T-RAIM processing is used to eliminate any aberrant satellite signals from the timing solution. The result is timing precision on all outputs with accuracy similar to that normally seen only in laboratory instruments. It synchronizes a wide variety of microprocessor-based power system equipment including: SCADA systems, remote terminal units (RTUs), protection relays, sequence of event recorders, digital fault recorders, tariff meters, Slave Display Units, Data Loggers and other Intelligent Electronic Devices (IEDs).