Method And Software Implementationof High-frame Positioning For Underwater Target

As the high attentionsof countries around the world on coastal defense construction and marine rights and interests,acoustic positioning technology as the most effective underwater positioning and navigation means,is an important component of the national marine disciplines.In this paper,three-dimensional trajectory measurement method for underwater targets with high frame rate and the rangeambiguityresolving technologywhich is developed to ensure the effective positioning algorithm are studied,and these algorithmsare implemented on the display and control platform.Underwater targets horizontal trajectory measurement is based on the long baseline and ultra-short baseline acoustic combination positioning system,each positioning system work independently.Firstly,the synchronous and asynchronous solution methods of the long baseline system,the ultra-short baseline solution method and their positioning accuracies are analyzed.Then a multi-solution fusion method on account of the minimum mean square error is used to obtain higher positioning accuracy.With the existence of redundant information,the combined positioning systemenhancesits stability,but arguments the system’s complexity.The method of double-pulse sounding is adopted in themeasuring of vertical direction.Considering that the expansion or compression of the pulse caused by high-speed motion may make the pulse width of receiver and transmitter different,the Doppler correction technology is used to make the depth measuremore accurate.In order to achieve high frame rate positioning,the synchronization period is very short,which brings about the range ambiguity problem.The range ambiguity resolvingmethod of long baseline is the key technique to determine the real propagation period of the signal and guarantee the core positioning algorithm effectively.In this paper,the theories of hand-voting,initial position marking,anti-ambiguity with azimuth information and anti-ambiguity with pulse combination are analyzed and simulated respectively.The performance of range ambiguity resolving has become one of the standardsto evaluate the high frame rate positioning system.In the process of implementing positioning solution software,the whole structure frame is determined firstly.According to the function,the software is divided into modules with independent function and low coupling.The design ideas and implementation methods of modulesincluding direct pulse selection,buoy selection,depth measuring,rangeambiguity resolution and positioning solution are introduced emphatically.These modulescoordinate with each other,so that the software has the capabilities with high frame rate and high precision positioning.The software is verified by laboratory electricconnection debugging and the field experience in order to test its function.The paper analyzes the measurement results,proving the effectiveness and practicability of above-mentioned algorithms,and the stableness and dependability of the positioning software.