Research On The Effection Of Frequency Characteristics Of Excitation Signal On Underwater Active Electrolocation System

The Underwater Active Electrolocation technology is a kind of underwater positioning and environmental awareness of technology,which is based on the low-frequency weak electric field.The detect Frequency Dead Zone(DFDZ)and the Frequency Inflection Point(FIP)of the Amplitude Information-Frequency Characteristics(AIFC)for the electrolocation system can effectively reflect the information of detected objects such as the material,shape,conductivity.Thus,it is very significant to obtain the FIP of detected objects for the identification of underwater objects.The underwater active electrolocation system based on the single frequency excitation signal can accurately get the FIP of detected objects,but operation is complicated and it is difficult to apply in the actual work environment due to the limit of frequency sweep.In order to simplify the retrieval process of FIP,the multiple frequency excitation signals are adopted to study the frequency features of excitation signal how to influence on the active electrolocation system.We establish the underwater active electrolocation system based on the Fourier transform superposition principle.The experimental results of different shapes and materials under the different excitation signals(square wave,single peak pulse and double peak pulse)are studied.In this paper,the underwater active electrolocation experiments based on single frequency and multi-frequency excitation signals are carried out.By comparing the experimental results and analyzing the JTFS of different excitation in the same materials and object,the feasibility of obtaining DFDZ and FIP using multi-frequency excitation signal is verified.After summarizing the whole research process,the following conclusions can be obtained:1.The multi-frequency excitation signal can be used to effectively calculate the FIP of the underwater active electrolocation system only through one scan.When the FIP of detected object is low,the result is similar to that of the sine signal,and the result is deviated from the single frequency signal when the object has a higher FIP.2.There is no DFDZ and FIP phenomenon for the plastic detected object under multi-frequency excitation signal,which is consistent with the result of single frequency excitation signal.3.The algorithm can accurately obtain the DFDZ and FIP of the probed objects,and eliminate the interference due to various frequency components in the spectra.Therefore,it is reasonable for us based on the experimental results to assume that the underwater active electrolocation system is a linear system at low frequency.This will help us to understand the physical mechanism of the active electrolocation system more deeply.