NBOSI offers conductivity-temperature sensors for mobile marine platforms including underwater vehicles (AUV/UUV),  surface vehicles (ASV/USV), remotely-operated vehicles (ROV) and underwater gliders. We can provide sensors in either cabled or hull-mount versions in a range of mechanical configurations and power/data interfaces. Custom engineering is available to support your specific sensor integration requirements. An optional pressure sensor can be included to provide backup vehicle depth sensing and accurate ocean density and sound speed.



Awkward non-hydrodynamic sensors can be hard to integrate
Compact, AUV-optimized geometry reduces drag without compromising measurement quality.
Electric field proximity effects constrain inductive sensor mounting options and make accurate calibration and field repair challenging
Contained electric field allows the NBOSI sensor to be mounted anywhere and calibrated independently from its host platform
Pumped sensors consume energy and generate noise and vibration
Free-flushing CT cell provides low-power, low-drag, silent operation with excellent dynamic response
Off-the-shelf solutions limit innovation
NBOSI offers custom engineering  to support any platform or application


Cartoon of Conductivity Cell Electric Field and Current

The NBOSI Conductivity-Temperature (CT) Sensor is based on a design by the late WHOI engineer Neil Brown for a novel four-electrode conductivity cell with an internal electric field (US Patent 6,720,773). NBOSI implemented and optimized this design for integration with mobile marine platforms including AUVs, ASVs, ROVs, and underwater gliders.  

A low-thermal-mass open conductivity cell with an internal fast-response temperature probe provides research-quality T & C data with excellent dynamic response and high spatial resolution. Unlike existing two-electrode cells the NBOSI CT sensor does not require an energy-consuming and noisy pump. And unlike inductive cells the compact, low-drag NBOSI sensor may be mounted anywhere on the vehicle exterior without compromising data quality. The four-electrode, contained-field configuration is inherently insensitive to electrode fouling and can be mounted anywhere without compromising cell calibration.

The NBOSI CT Sensor is rugged, snag-proof, and resistant to fouling. An advanced self-referencing transformer-based electronic design corrects for thermal drift of components providing stable, low-noise performance.  The sensor can be calibrated independently of its host vehicle allowing for ease of field replacement and repair. A simple RS-232 data interface facilitates vehicle integration and provides raw or engineering-unit data at up to 10Hz. Direct output of density and sound speed is available with an optional pressure sensor.

The NBOSI CT Sensor is currently available in two basic styles: Cabled or Hull-Mount. We would be happy to work with you to develop a custom sensor configuration for your application.

Cabled CT sensor

The NBOSI Cabled CT sensor consists of an internal field, four-electrode conductivity cell with an integral, pressure-protected thermistor and a high precision, self-referencing electronics board.  The Cabled CT cell is available in a range of standard cable lengths and connector types.

Cabled CT cell with electronics boardCabled CT sensor


The NBOSI Hull-Mount CT sensor consists of an internal field, four-electrode conductivity cell with an integral, pressure-protected thermistor and a high precision, self-referencing electronics board. Custom mounting arrangements and hull penetrators are available for any application.

CT cell hull mount on AUVHull-mount CT cell