Novel Self-Calibrating pH Sensor for Use on Autonomous Underwater Vehicles.

The overall objective of this project is to research, develop and produce and demonstrate a prototype pH sensor, utilising a novel self-calibration system, onboard an AUV to a depth of 250 metres.

The absorption of CO2 is causing detrimental changes to ocean chemistry. When CO2 reacts with water, carbonic acid is produced causing 'ocean acidification' which is having adverse effects on marine life, including; fisheries, fish farms, shellfish banks and coral reefs. A vast number of sensors will be required to gather the data necessary to understand ocean acidification and its effects, however this is currently not possible due to expense. AUVs are proposed as the solution to the need for making numerous measurements across the World's oceans. The proposed solution is to provide swarms of low cost, small AUVs that collect data for extended periods of time. As such, AUVs are a rapidly growing platform for ocean and water monitoring/management. However, to fulfil the role of a data collection platform, AUV's need sensors that can be deployed on the small/low cost AUV, which requires low cost, small, calibration free sensors.

ANB Sensors Ltd (ANB), a UK micro-SME, have identified and filed patents on a disruptive enabling technology, which allows the measurement of pH in demanding (low-salt and low-buffer capacity) aqueous media, such as drinking and seawater. The technology provides accurate measurements (+/- 0.01 pH units), without the need to re-calibrate the sensor; differentiating it from the state-of-the-art. The calibration free operation of ANB's pHenom sensor and its small size mean that the sensor is ideal for use onboard AUVs. This will unlock their wide spread use as data collection platform for ocean and water monitoring/management.