Compact Long-Range Underwater Velocity Sensor

Most UUV payload systems require high navigational accuracy for target localization. Once the vehicle dives from the surface, it is dependent upon a velocity log to maintain navigational accuracy. Thus, DVL bottom lock range effectively limits the water depth in which target localization missions can be prosecuted. The team proposes to pair a 150 kHz DVL with a 600 kHz DVL. The performance of this dual frequency sensor will be less dependent on water column properties because the low frequency transducer will provide sufficient performance margin at high altitudes while the high frequency transducer will provide measurement accuracy at low altitudes that is sufficient for synthetic aperture sonars. The resulting DVL sensor will be ideal for integration with existing inertial navigation systems (e.g. Kearfott, IxSea). The team shall implement a sensor fusion algorithm that augments the DVL velocity estimates with data from the inertial measurement sensors (accelerometers and rate gyros) to produce a more accurate velocity estimate than is possible with the DVL alone. Additionally, auto-tuning algorithms that will reduce configuration requirements for the field operator will be investigated. High fidelity simulation of acoustics, vehicle dynamics, and the operating environment will be integral to the design process.