水声中非直达声下的声速修正方法  

A sound speed correction method for non direct arrived ray in underwater acoustic

作　　者：杨磊 金诸斌 刘祖斌 卢奂采[1] YANG Lei;JING Zhubin;LIU Zubin;LU Huancai(Key Laboratory of Special Purpose Equipment and Advanced Manufacturing Technology,Ministry of Education,Zhejiang University of Technology,Hangzhou 310014)

机构地区：[1]浙江工业大学特种装备制造与先进加工技术教育部重点实验室,杭州310014

出　　处：《高技术通讯》2022年第12期1312-1322,共11页Chinese High Technology Letters

基　　金：国家重点研发计划(2017YFC0306202);国家自然科学基金(61601407,51975525);浙江省自然科学基金(LY20A040007)资助项目。

摘　　要：在水下声学定位系统中,声线弯曲是影响定位精度提高的重要因素。基于水下射线模型的声速修正方法,通过迭代法计算声源和接收点间所有本征声线后再获取首达声线信息的方式实现。但是,已有的本征声线计算方法鲜有提及声线传播经历多跨度或反转点对于迭代法结果的影响,前者会造成初始掠射角搜索时的迭代区间受到限制,后者则会造成声线传播水平距离与初始掠射角变呈非单调关系,迭代常会失效。本文提出了一种非直达声下的声速修正方法,首先对声线初始掠射角区间进行两次分类,依据是反转点是否存在和经历的跨度数;其次利用迭代法分别计算不同跨度区间内的本征声线,并且特别对包含反转点的跨度区间要采取先预处理再迭代的方式;最后获取首达声线的时延信息即可计算出有效声速。以中国南海某地声速剖面为例,分别计算了声源位于2次不同深度下的区域有效声速,结果表明该算法在非直达声条件下依然可以精准计算任意一点的有效声速。In underwater acoustic positioning system,the bending of sound ray is an important factor influencing the posi-tioning accuracy based on underwater ray model,and the sound velocity correction method is realized by finding the first arrived ray among all the eigenrays between the sound source and the receiver through iteration calculation.But the present methods rarely mention that if the first arrived ray pass by multi-span and inversion point or not will have distinct influence on the result.The former condition will lead to the limitation of the iterative range when searching the initial grazing angle,while the latter condition will cause a non-monotonic relationship between the horizontal distance of ray propagation and the initial grazing angle,and an invalid iteration.A sound velocity cor-rection method for non direct arrived rays is proposed here.At first,the initial grazing angle range will be divided twice by the algorithm,according to the number of spans passed by and the existence of inversion point;secondly,the eigenrays are calculated by iteration method in each range with different spans,and especially for the range which includes inversion point it has to do preprocessing before the iteration;in the end,the effective sound speed will be calculated after obtaining the propagation distance and time of the first arrived ray.Taking the sound speed profile of one place in South China Sea as an example,the regional effective sound velocity is calculated when the sound source is put in two different depths.The results indicate that the new method can accurately calculate the effective sound velocity at any position even for non-direct arrived ray,furthermore,it can calculate the effective sound velocity for the whole ocean.

关 键 词：声速修正 非直达声 迭代法 多跨度 反转点 有效声速 

分 类 号：TB56[交通运输工程—水声工程]