Integrated Navigation System Design For Autonomous Underwater Platform

High precision navigation and positioning is the requisite for autonomous underwater platform to achieve location-specific operation.Limited by environment,it is impossible to correct position through Global Positioning System underwater.To ensure the execution of task,integrated navigation system with ability to integrate navigation data from motion sensors is necessary.External position information with ability to be transmitted underwater for position correction is necessary for the purpose of overcoming the influence of accumulated error.Motion sensors and acoustic communication/positioning device are studied in this paper to improve the navigation accuracy which is the requirement of underwater position control and task execution.With the purpose of improving navigation accuracy,the velocity from Doppler Velocity Log(DVL)is integrated to inertial navigation system as the correction of estimated velocity.The position calculated by inertial navigation system/DVL integrated navigation system meet the requirement of underwater platform in short time.Due to accumulated error of subsystems,the error of integrated navigation system in long-time underwater task will be considerable.An acoustic communication/positioning system is augmented to deal with accumulated error.The navigation information sent to underwater platform through acoustic communication corrects the position of integrated navigation system periodically.Tank tests indicate the effectiveness of position correction method of acoustic communication/positioning system.The inertial navigation system/DVL navigation system and USBL position correction plan are combined as an integrated navigation system for autonomous underwater platform.Both the short-term and long-term performance of integrated navigation system are verified through two-step lake experiment.Simulation and experiment results show that the integrated navigation system has desirable navigation performance for autonomous underwater platform.Both frequency requirement in short–term task and precision requirement in long-term task are met with the integrated navigation system.