The algorithms of unmanned underwater vehicle motion detection based on image processing are considered in the paper. The approach is based on detection of the same objects on the consecutive frames and their joint displacement calculation. The motion detection system structure and algorithms of their operation onboard of UUV TSL are considered and results of marine trials are supplemented.
High precise motion detection of unmanned underwater vehicle/UUV/is important task for UUV station-keeping or docking in the presence of various types of disturbances such as underwater currents or sea waves. The station-keeping mode is intended for maintaining of particular position and orientation of UUV without continuous operator supervision. This mode is a critical UUV capability for inspection and repair of underwater construction, bottom data collection and surveillance missions. Usually the UUV navigation system is based on autonomous onboard reckoning system. It consists of velocity log (absolute or relative), heading meter (flux gate or gyro compass) and depth meter. UUV position is estimated by velocity components calculation and integration. The constant error in velocitymeasuring d v leads to the error dr= t*d v in position estimation. Doppler velocity log /DVL/ is usually used for UUV speed measuring. Modern DVL has the precision of about 0.2% ± 1 mm/sec. The error of position estimation is about 8 meters per hour of operation when the UUV velocity is 1 m/s. The constant error in heading dj leads to the error in the vehicle location of about dr≈ t* v*dj. The heading error of 2° is usual for magnetic transducer allowing for deviation. It can reach up to 10° and more in the regions of anomaly or near the big mass of magnetic materials However, currently FOGhasnot beenwidely used on themean cost UUVbecause of its high price.
