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The Locator-S1 carries an internal GPS based time sync module. Because of this, the S1 does not require tether integration for top-side communication. It only requires external power 10-18V to be provided from the underwater device.

Some Locator-S1 attributes can be configured using an integrated UART interface. This configuration is optional and not required for normal operation. Before deployment in water, the Locator-S1 needs to achieve a GPS lock. The integrated status-LED shows the condition of the GPS lock.


The default channel for Locator-S1 is 17 on boot.

As the Locator-S1 does not carry its own depth sensor, the depth needs to be provided from the underwater vehicle (ROV etc.) to the topside Master-D1 using the software API. Example of how to perform this can be found here.

LED Signals

  • Flashing green light (fast): Searching for GPS lock. The unit is not ready to dive.

  • Fixed green light: GPS lock is acheived. The unit is ready to dive.

  • Flashing green light (slow): GPS lock has been acheived but lost. The unit is ready to dive.

  • No green light: Power is off and the unit is not ready for diving.


  • GPS based sync removes all tether requirements enabling very easy integration with any ROV.

  • Extremely small size making it perfect for even the smallest underwater vehicles.

  • Highly robust operation in areas with reflections (shallow water, around installations etc.)

Wiring interface

The tables below shows the pinning of the S1 interface.

Interface Color
Positive (10-18V) Orange
Negative Orange/White
UART TX Brown/White

Terminal Interface

The Locator-S1 has a simple UART interface which is used to change the channel of the locator.

Settings Value
Baud rate 9600
Data parity stop 8N1
Flow control None