For any seismic data acquisition work, one of the most precious pieces of information is the exact time. Every OBS needs to be time synchronized so that data can be compared based on timestamps. Precision is paramount.

GPS is the most common method of synchronization used today, However, many low-cost GPS receivers lack a pulse-per-second (PPS) signal and their time measurement usually has high latency and jitter. Fortunately, our GNSS antenna, UHURA, is designed to work with GPS, GLONASS and Galileo.

UHURA provides NMEA-data using RS485 with both 4800 baud and 9600 baud. An extra line provides a latency-free, DCF77 encoded PPS signal. This makes it possible to achieve precise synchronisation of systems that would otherwise need an extra radio receiver.

UHURA can be equipped with cable lengths up to 100m, and the connecting plug can slip through orifices of 20mm diameter. It can be fixed to vessel railings with the provided clamp and is designed to withstand strong winds and temperatures ranging from between -10 to +85 °C.

UHURA is connected to the distribution box DIRC for its power supply and to enable the distribution of data. DIRC is the control centre for the OBS, ensuring optimal time synchronisation, positioning and data recovery – all within a robust, compact, lightweight, waterproof and dustproof case.

DIRC allows the user to connect a PC to both the OBS data logger and UHURA for time synchronization and for data collection either through an SD-card or StiK port. DIRC can also accommodate an external hard drive for additional storage capacity. Finally, DIRC can establish a wireless access-point to communicate with the data logger using any Wi-Fi enabled device.


  • OBS and other subsea or underground systems

Features / Benefits:

  • Very fast Time-to-First-Fix
  • Shock-resistant
  • Waterproof
  • LED status indicator in a housing
  • Dustproof
  • Breakproof
Protocol NMEA via RS485 @ 4800 baud and 9600 baud
Supported positioning systems GPS, GLONASS, Galileo, BEIDOU
Timing Information PPS-line DCF77 coded
Power consumption 5 Volt operation (USB)
Cable length Up to 100 m
Operational temperature range -10 to +85°C
Dimensions Diameter – 140 mm, Height – 95 mm
Ports USB, Ethernet, SD-card, StiK, Wi-Fi
Memory External Hard drive, SD card reader, StiK
Operational temperature range -10 to +50°C
Dimensions Length – 228 mm, Width – 182 mm, Height – 92 mm