GNSS and Atomic Clock Applications and Expectations for Field Testing
Presented by VeEX
This demo focuses on small built-in GNSS receivers and atomic clocks currently used for field testing and their different characteristics, functions and applications. Including, free-run characteristics, GNSS survey, disciplining, transport time, holdover expectations, battery autonomy, as well as their challenges and limitations. VeEX will show the process of getting the precision oscillator disciplined to GNSS/UTC timing (normally done outside), put the instrument into sleep mode, carrying the timing in holdover (e.g. to allow transportation and pass security check points) and still be able to be used indoors to measure wander and verify time error.
Acquiring, maintaining and carrying UTC-aligned 1PPS timing into indoor locations, without GNSS coverage, for testing purposes has always been a challenge. From a controlled lab point of view, this may look trivial, but from real-life field operations perspective there are many challenges to overcome in order to assure accurate results. Practical field solutions have to deal with lack of on-site clock references, power consumption, battery autonomy, temperature variation, Time Error (TE) drift, among other factors.
From Frequency delivery point of view, this may not look that difficult: Calibrate the built-in precision oscillator and rely on its frequency retrace (repeatability) characteristics. Transporting Phase or Timing, on the other hand, may not be that simple.
Four years of field testing and research allowed VeEX to be the first in defining a practical timing/phase reference delivery solution for field test and measurement, based on miniature atomic oscillators.