# Use Cases

Ultra Low-Power Micro OCXO for Underwater Systems


Problem We Solve

Unmanned Aerial Vehicles (UAVs) – especially those underwater – need to have reliable navigation systems, to ensure continued operation at all times. Losing the signals necessary for positioning and navigation, even momentarily, could become hazardous. Fully autonomous UAVs are even more dependent on communication signals with the mother ship, autopilot and other radar sensors.

Because of the relatively weak signal power (-130 dBm), GPS signals can easily be disrupted by unintentional noise or intentional jamming transmitters. And underwater, the signals are essentially non-existent.

Marine engineers and UAV manufacturers need ways to provide timing and positioning signals to underwater vehicles in order to ensure the continued operation of mission-critical equipment, such as on-board navigation systems.

Why it is Important

If an underwater UAV loses its navigation and communication capability during a mission, it can be potentially dangerous, as it can be guided off course causing it to crash.

The more a UAV relies on an internal navigation system, the more it is necessary to have a stable frequency source to ensure continued operation.

How We Solve it

Safran provides reliable and robust atomic clocks and oscillators for UAVs and other vehicles to use when GPS signals are not available. These oscillators ensure that the systems on board have a constant source of time and frequency. They can range from master crystal oscillators used on satellites themselves, to rubidium oscillators, to crystal oscillators for underwater autonomous vehicles. Let’s take a closer look at some of the these solutions.

EWOS-16 UW OCXO Crystal Oscillator

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EWOS16-UW is a customized micro-OCXO for underwater systems with a record low power consumption at 50 mW at 25°C to optimize the mission time and downsize the battery.

Powered with 5V, the EWOS16-UW delivers an ultra-stable frequency of 16.384 MHz with a record low thermal sensitivity typically (±30 ppb between -10°C and +50°C). EWOS16 can be disciplined thanks to its tuning pin and is highly resistant to shocks and vibrations.


The third layer of defense is having a backup source of navigation and motion tracking, in case your UAV goes off course from a spoofing attack. If your UAV performs a critical task that requires a GPS backup, and you cannot afford the risk of a system failure due to intentional or unintentional GPS interruption, then the VersaPNT is an ideal solution. The three main benefits of the VersaPNT are:

Resilient – High performance internal time base and inertial sensor to manage potential GNSS signal loss.

Configurable – Configurable for multiple UAV and airframe platforms.

Rugged – MIL-STD-810G low size, weight and power to enable seamless integration into your UAV system.

Why Choose Us

  • Easy UAV Integration – the EWOS16-UW OCXO can easily be embedded into an underwater UAV because it was designed to support mobile applications.
  • Resilient – By adding a secure, robust timing system that can be used for navigation and positioning in environments where there is no GPS, your UAV will be more resilient.
  • Low SWAP – the EWOS16-UW measures less than 20mm x 12mm x 6 mm and weighs less than 4g – one of the lowest SWaP solutions in the market.
  • Rugged – It’s designed for harsh environments (-10˚C to +45˚C operating temperature), as well as disruptive shocks and vibrations.

Discuss Your Solution

LWOS16 v1

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