Multifunctional Beidou Emergency Position Indicating Radio Beacon For Intelligent Fishery

China is a big country in marine fisheries with developed marine fishing and marine aquaculture,but it is also facing a huge challenge of transforming traditional fisheries into intelligent fisheries.Fishing boats are one of the main bodies of intelligent fishery construction.Emergency position indicating radio beacon(EPIRB)is a emergency radio positioning equipment widely used in shipping,and play an important role when fishing boats are in distress.The all-weather,whole-day,highprecision positioning and navigation and beidou short message transmission and timing work can be supplied for all global users,after completion of beidou navigation satellite system(BDS-3)global networking in 2020.According to the needs of marine fishery enterprises in China to build intelligent fisheries,the new EPIRB based on the emergency rescue function should also have the function of ship-shore fishery information interaction,so as to meet the informatization and intelligence level of fishing vessels.Therefore,on the basis of beidou positioning and short message communication technology,this paper designs a new type of multi-functional EPIRB based on low-power microcontroller,WIFI modules and angle sensors,etc.In order to make EPIRB have better stability,this paper designs the structure of EPIRB.First,for the purpose of lowering the effect of wave and wind load on EPIRB,it is determined that the upper part of the position indicator float is spherical and the lower part is cylindrical.Second,in order to ensure the rationality of the hardware assembly of EPIRB and fully improve its space utilization,the internal structure of the EPIRB is designed,and the minimum diameter D and height H of EPIRB are determined;control the diameter of the position indicator floating body D or height H remains unchanged,and 25 position indicator models with different dimension parameters are designed.By comparing the roll response RAO under the same wave environment,three sets of better solutions are selected.Finally,according to the stability requirements of EPIRB in the marine environment,the initial stability and natural period of EPIRB are compared and analyzed,and the force of EPIRB in waves under severe sea conditions is studied through the AQWA software;the analysis shows that the Froude-Kriloff force and the first-order linear wave force have the greatest influence on EPIRB in the heave direction,and the diffraction force has a more obvious effect in the heave direction,but the curves of the three have gentle changes in the main energy frequency of the wave,the possibility of resonance of EPIRB is small;the additional mass coefficient and additional damping have little influence on EPIRB in the main frequency range of the wave,and the possibility of resonance in this range is small.By comparing the force difference of EPIRB buoy in the waves of three different size design schemes,it is found that EPIRB buoy has the best hydrodynamic performance when the diameter D is 0.20 m and the height is0.16 m.EPIRB is processed according to this size,and the buoyancy test is carried out to verify the rationality of the structural design.On the basis of the emergency rescue function of EPIRB,this paper builds a fishery information platform based on the beidou communication architecture to realize the interaction of ship-shore fishery information.When the fishing boat is sailing normally,the onboard industrial computer completes the collection of fishery information,and sends it to EPIRB through the onboard LAN.EPIRB sends the fishery information to the enterprise cloud platform through beidou short messages,and onshore users can register the enterprise cloud platform to view.In addition,the influence of attitude change of EPIRB on the delivery rate of short messages in a complex water environment is studied in this paper.And this paper proposes a short message sending mechanism based on the attitude of EPRIB,which is verified by comparative experiments.The results show that the short message sending mechanism based on the attitude of EPIRB can reduce the influence of EPIRB deflection on the delivery rate of short messages,and effectively improve the delivery rate of short messages.It is greatly significant for this research to increase informatization and intelligence level of the fishing vessels under the background of intelligent fishery and to ensure the safety of lives and properties of fishermen.