Research On Multi-source Navigation And Preventing Collisions Technology Of Unmanned Surface Vehicle For Submarine Pipeline Survey In Offshore Waters

Surveying the submarine pipelines by the unmanned surface vehicle(USV)is a new means which has the advantages of high operating efficiency,wide range,low cost and good environmental adaptability.However,due to the long-time operation and the unpredictable changes in the surrounding environment,some problems need to be solved:(1)Long-time,reliable and high-precision navigation.If necessary,it will be able to provide navigation enhancement service to the underwater unmanned system;(2)Water traffic is relatively heavy in the offshore areas,so effective preventing collisions under rules is the key to safe navigation and operations.In response to the above problems,research in the topic has been carried out on key technologies such as multi-source navigation,cooperative navigation and preventing collisions for USV.The main research contents include:(1)The INS/GNSS/DVL integrated navigation scheme and Kalman filter algorithm are proposed,which can provides precise location information for the navigation and operation of the USV.In the cooperative navigation of the USV and the unmanned underwater vehicle(UUV),an improved cooperative navigation method based on USBL is proposed,which reduce the position error of the UUV to 10 m.A linear PID control method based on the line-of-sight method is used to keep the USV and UUV within effective communication,positioning distance and angle range.The distance error is less than 15 meters and the angle change is less than 1o.which solve the unsteadiness in the cooperation navigation.(2)For the preventing collisions problem between cooperative targets with good navigation information swaps,a method is proposed for identifying the navigation mode based on preventing collisions rules.The USV behavior prediction model based on the optimal target under constrains is established considering the difference in the targets’ behavior patterns and the driver’s control behavior,in order to obtain the reference track clusters of the other targets for USV to effectively avoid collision under the rules.(3)For the preventing the close collisions problem of non-cooperative and non-confrontation targets with no information swaps,attitude compensation was made to the navigation information of other ships acquired by radar.A method of using the overlapping degree of space security area to create a collision risk index(CRI)assessment model was proposed.And based on this,the timing,method and algorithm of preventing collisions in close range are proposed.The simulation and real ship experiments verify the effectiveness of this method.The main innovations of this paper include:1.An improved cooperative navigation method based on USBL is proposed,which reduce the position error of the UUV to 10 m.A linear PID control method based on line-of-sight way is proposed,which make the USV and the UUV always maintain the right distance and angle,and communication and cooperative navigation can be stable and continuous.2.Based on the optimal target theory and method under multiple constraints,a model for predicting ship navigation mode under collision avoidance rules was created.3.A collision risk CRI assessment method is proposed,which based on the overlap of space safety zones and creates a close-range CRI assessment model for non-cooperative and nonconfrontation target vessels.