Design And Implementation Of Low-power Data Relay Subsurface Buoy

Subsurface buoy is a common equipment in underwater acoustic field,which is widely used in underwater acoustic communication,positioning,navigation,marine environment monitoring and other scenarios.The subsurface buoy designed in this paper has the feature of multifunctional,low-power.Its main function is to relay underwater acoustic spread spectrum signals,which can be applied to underwater acoustic communication scenes to extend the propagation distance of the spread spectrum underwater acoustic signals,so as to expand the range of the whole underwater communication network.In addition,this subsurface buoy can also be applied to underwater acoustic location and navigation scene,to play the role of a transponder.First,according to the actual working scene of the subsurface buoy,the spread spectrum signal form used by the subsurface buoy is designed and the hardware overall scheme is designed.Through simulation,the detection performance of different parameters of direct sequence spread spectrum signal using BPSK modulation under the influence of underwater acoustic channel is compared and analyzed.According to the results of simulation,the signal parameters used by the subsurface buoy are determined,and the communication protocols for the subsurface buoy in spread spectrum relay mode is designed.After that,the signal processing method of subsurface buoy is designed.The signal forms to be processed include LFM,spread spectrum and CW signal.Copy-correlation method is used to process LFM signals.A RAKE receiver is used to deal with spread spectrum signals to suppress the influence of multipath effect.CW signal is processed by adaptive Notch filter and VIFD.The principles of these methods are introduced and the simulation analysis is carried out.The influence of different structures and parameters on the performance of RAKE receiver is analyzed emphatically.Then,according to the overall scheme design and signal processing method,the hardware circuit and software program of the subsurface buoy are designed.In the hardware chip selection and circuit design,uphold the design principle of low power consumption,and then through circuit modular design,power supply dynamic management,standby on duty and other ways to reduce the power consumption of the whole system.In the software program design,the emphasis is placed on the realization of various signal processing and detection algorithms on DSP chip,as well as the work flow under various working modes.Finally,each function of the subsurface buoy is verified one by one in the laboratory and pool.The experiment proves that the hardware circuit of the subsurface buoy is normal and the software program is stable and reliable.The subsurface buoy can complete the expected tasks in various operating modes,and satisfied the various technical indicators proposed.