Research On Underwater Current Field Detection Technology Based On Weakly Electric Fish Bionics

As we all know,the surface of the earth is mostly covered by water.The exploration of underwater space has become an important issue.In the offshore waters of China,a large number of underwater pipelines have been arranged,which has correspondingly generated the demand for underwater detection technology.In the military field,a large number of underwater reconnaissance equipment,such as the US military's Sound Serveillance System(SOSUS),has been installed in the waters near the first island chain in China,which has formed an underwater blockade situation in China.Conventional underwater detection methods have many problems when performing underwater detection.For example,underwater acoustic detection technology has the disadvantages of complicated and expensive equipment,and is susceptible to interference in environments with complex underwater acoustic conditions such as offshore waters.Underwater television technology is limited by the limited transmission distance of light underwater and cannot be used in turbid waters.The current field detection technology based on weakly electric fish is a new underwater detection technology.It is expected to solve the problem that traditional underwater detection technology is susceptible to interference and limited use scenarios.This technique is derived from the bionics research on weak electric fish,which generates a low-frequency electric field under water to sense the disturbance caused by surrounding objects,and then complete the detection.Although the current field detection technology is still in the stage of initial exploration,due to its simple structure and strong antiinterference ability,it is very suitable for application in offshore turbid waters.It can be widely used in submarine pipeline detection,underwater detection wreck searching and other fields.The main research content of this paper is to study the detection and location algorithm based on the principle of current field detection,and design a current field based detection system.The specific research contents are as follows:Firstly,based on the principle of current field detection,the electric field mathematical model of electric dipole under water detection is constructed.Taking the sphere as an example,the model of the disturbance of the detected object is proposed and the relevant formula is derived.The Ansoft Maxwell software was used to simulate the effect of the material and positioning of the model on the object.The influencing factors were analyzed and the feasibility based on current field detection was verified.It provides theoretical support for the research of the detection and localization algorithm.Then,a detection algorithm based on digital correlation method is proposed to detect the electric field disturbance caused by external objects entering the current field.The amplitude and phase changes of the electric field generated by this disturbance are captured,and then the neural network algorithm is introduced to study the positioning algorithm.Aiming at the disadvantages of BP neural network with poor positioning accuracy and slow convergence speed,the RBF neural network was used for localization.The cross-validation and generalized regression algorithms are combined with the characteristics of the system to improve the RBF neural network and improve the positioning accuracy.Finally,an underwater current field detection system was designed.In view of the fact that the received underwater signal is weak and the amplitude of change is small,the design of the detection system focuses on reducing noise and amplifying the signal.Carbon fiber electrodes with high sensitivity and stable performance are used in the selection of electrodes.Noise reduction and isolation are considered when designing the power system.A low noise instrumentation amplifier is used in the signal processing system and the signal is filtered.Periodic smoothing is used in FPGA programming to suppress random noise.In the upper computer program,the time slot is used for calculation to make reasonable use of computing resources.After testing,the detection system can detect underwater objects.