GPS NTP Time Server Product

Overview

A GPS NTP time server is the device that gives a network its sense of time. It sits in a rack, listens to navigation satellites through a roof antenna, and answers Network Time Protocol queries as a stratum-1 source — one hop from the atomic clocks aboard the GNSS constellations. Trading floors timestamp orders against it, telecom networks frame against it, and ordinary enterprises use it so that log files from a thousand machines can be correlated to the millisecond.

Functionally it is three instruments in one box: the GNSS Receiver recovers UTC from the sky, the Disciplined Oscillator smooths and stores it, and the Network Board retails it over Ethernet. The Antenna Kit on the roof is as much a part of the product as the chassis.

Recovering time from satellites

Every GNSS satellite carries atomic clocks and broadcasts its time and orbit continuously; a receiver solving for position is really solving for position and time together. The GNSS Module is a timing-grade receiver that exploits a fixed installation: after a self-survey of several hours establishes the antenna position permanently, all satellite measurements collapse into a single unknown — time — and the module's pulse-per-second output aligns to UTC within roughly 5–15 ns. Signals arrive at about −130 dBm, below the thermal noise floor, so the LNA & Filter and the antenna's own 30–40 dB preamplifier do the heavy lifting, while a SAW filter keeps adjacent cellular bands out. Cable delay matters at this precision: the 30–60 m of Coax Cable from the Antenna Element adds about 4 ns per metre, entered as a calibration constant. The Surge Arrestor exists because that same cable is a lightning conductor terminating in the server room.

The disciplined oscillator

Raw GNSS pulses are accurate but not dependable — jamming, antenna faults, or simple roof work can interrupt them. The OCXO is the flywheel that rides through: a crystal oscillator inside a miniature oven held near 70 °C, stable to a part in 10^10 per day. The Phase Comparator continuously measures the OCXO against the GNSS pulse-per-second, and a slow control loop steers the oscillator through the Control DAC in steps of parts per trillion. While satellites are visible, the OCXO is a noise filter that removes the receiver's nanosecond-level jitter; when they vanish, the unit enters holdover and the OCXO carries the timescale alone, drifting less than ten microseconds per day. For most networks that means days of antenna outage before clients notice anything. Rubidium options stretch holdover into weeks at higher cost and power.

The oven is also why the Cooling Fan is positioned to ventilate the Rack Chassis without blowing on the oscillator: a draft modulates oven duty cycle, and that shows up as frequency wander.

Serving the network

The Compute SoC Module runs the NTP daemon, answering UDP port 123 queries at rates above ten thousand per second; an NTP response is small and stateless, so one 1U box covers a large enterprise. Precision clients use PTP instead, and that is where the Ethernet PHY earns its place: IEEE 1588 hardware timestamping stamps packets as they cross the wire, removing the operating system's scheduling jitter and bringing client sync from NTP's typical sub-millisecond down to sub-microsecond. The SFP Cage serves fiber-isolated segments, and the Memory Bank holds the OS, leap-second tables, and holdover logs. Management is web, SNMP, and syslog; the Front Panel with its LCD Panel, Status LEDs, and Keypad covers initial setup and the at-a-glance question every operator asks walking past: locked, or in holdover?

Infrastructure duties

Because everything downstream assumes the time server is up, the Power System is redundant: two hot-swap supplies behind an Inlet Filter, plus a telecom −48 V DC Input option, all inside a Fastener Set-assembled steel shell with Rack Ears. Total draw is 20–30 W, a third of it the oscillator oven.

Deployment practice repays attention. The antenna under its Antenna Radome needs an open horizon on its Mast Mount — multipath off rooftop structures is the dominant error source. Serious installations run two servers on opposite ends of the building with separate antennas, since NTP clients are designed to vote among sources. And operators increasingly enable multi-constellation reception not for accuracy but for integrity: GPS jamming incidents near ports and airports are now routine enough that a stratum-1 source watching four constellations, with an OCXO ready to coast through the gap, is the difference between an alarm and an outage.