Disciplined Oscillator White-Rabbit


High performance GPS grandmaster clock and network time server capable of distributing GPS Time or UTC using White Rabbit networks with sub-nanosecond accuracy over long-distance fiber links (typically hundreds of km). The DOWR is built as a white box solution, including timing integrity monitoring of the GPS navigation data. It provides raw GPS data for the calculation of a precise antenna position and for legal traceability to UTC(k) laboratories (Figure 1).

GPS and White Rabbit come fully calibrated from factory for the provided antenna cable. Additionally, the DOWR distributes time to other equipment via standard protocols such as PTP, NTP and IRIG-B.

Figure 1 – Traceability to UTC(k) laboratories evaluation setup (left image). Traceability of GPS Time from the M8F (DOWR) and M8T receivers to UTC(ROA) (image). (Extracted from R. Píriz et al. “Practical Traceability to UTC(k) from a GNSS Timing Receiver”, ISPCS 2018, October 3rd, Geneva, Switzerland)


– Timing protocols: NTP, IEEE 1588v2 and White Rabbit.
– Sub-nanosecond accurate time distribution for long distance networks.
– User-friendly web management interface.
– Optional oscillator for extended hold-over (1.5 µs after one day).
– Built as a White-box GPS receiver.
– GPS working modes: Free Position, Fixed Position and Survey-in.
– GPS raw data for the calculation of a precise antenna position and for traceability to UTC(k) labs.
– Full GPS and White Rabbit calibration for the provided antenna cable.
– GPS timing error < 15 ns under normal ionospheric conditions (± 2 ns time-pulse jitter).


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DOWR User Guide