Kraken secures government funding for acoustic velocity sensorVessel & ROV News // January 23, 2013
Kraken Sonar Systems has signed a Contribution Agreement with the National Research Council of Canada Industrial Research Assistance Program (NRC IRAP). The funding will be applied to the development of AquaTrak, a Correlation Velocity Log (CVL) designed for underwater navigation.
AquaTrak will be used to measure the speed over ground of Unmanned Underwater Vehicles (UUVs) and can also be used for high resolution current profiling.
Accurate positioning is a significant problem in the operation of UUVs. While GPS can be used to provide navigational information to surface vessels, it does not work underwater. Presently, the primary technology used for underwater navigation and current profiling is the Doppler Velocity Log (DVL).
The CVL is similar to the DVL in that it uses sonar echoes from the seabed, however the CVL does not measure frequency shift but instead takes direct spatial measurements of vessel displacement between successive sonar transmissions using a sparse array of receiver elements.
The layout of the elements is optimized to allow for many possible displacement vectors with a small number of receiver elements, a specific array configuration known as 'minimum redundancy' which is used also by radio-astronomers to address the complexity of their instruments. This allows size, weight and power to be significantly reduced compared to the DVL while offering increased accuracy. Also, by operating at a lower frequency, the CVL offers increased operational range.
“CVL technology has received little attention for UUV applications - perhaps due to the intensive signal processing requirements. We believe we can now leverage the many advances in broadband transducer and digital electronics technology to provide a step change in performance” said Dr Marc Pinto, Chief Technology Officer for Kraken.
“Synthetic Aperture Sonar is an excellent example of this, as the correlation signal processing implemented in SAS to track vehicle displacement has been shown to deliver accuracies unachievable by other means.”
Karl Kenny, President and CEO for Kraken said, “We greatly appreciate the funding support from NRC IRAP to help us develop such an innovative sensor for underwater navigation. We expect that our AquaTrak CVL will provide a superior value proposition to customers as it will feature greater performance in speed, accuracy, and range; with lower size, weight, power and cost than conventional technology.”