【作者】 马敬广；

【导师】 惠俊英；

【作者基本信息】 哈尔滨工程大学 ， 水声工程， 2008， 博士

【摘要】 本文以目标被动定位为背景,研究了基于时间反转镜的目标被动定位技术。其目的在于:研究基于时间反转镜技术的目标被动定位算法。论文的主要研究工作集中在以下几个方面:第一,基于射线传播模型,根据声场的互易性原理,讨论了时间反转镜定位的基本原理,推导了时间反转镜定位的基本公式,建立了单元、二元、多元声压传感器和矢量传感器时间反转镜被动定位模型。研究表明,实现时间反转镜被动定位的关键是信道建模与实际海洋传播信道的匹配程度,也就是主动时间反转聚焦过程在信号处理中实现的程度。第二,用仿真数据验证了算法和程序的正确性,评估了时间反转镜被动定位算法的性能。利用射线传播模型计算了信道的传递函数;根据各被动定位公式,进行了目标二维(距传感器水平距离和水下深度)被动定位处理。仿真数据处理结果表明:时间反转镜被动定位算法能实现被动定位,且定位的精度达到了搜索步长(论文处理的最小步长是水平5米,深度2米);单水听器时间反转镜被动定位技术检测能力达-8dB,且随着阵元数增加,检测能力也随之提高。仿真结果还表明:时间反转镜处理增益不小于平面波假设下的处理增益。第三,处理了垂直阵海上试验数据,揭示了时间反转镜潜在的应用价值。海试数据处理表明:单元声压、矢量传感器时间反转镜处理即可实现被动定位;多元声压传感器阵时间反转镜的检测能力明显提高。但海试数据时间反转镜处理的定位精度远不如仿真数据处理结果,这就提出了时间反转镜被动定位新的研究内容,即信道建模的正确性和算法的宽容性研究。第四,进行了时间反转镜技术初步应用研究。物理时间反转镜可实现自动聚焦,自适应地克服多途效应对声纳性能的不利影响。湖试表明,采用物理时间反转镜和被动时间反转镜方法,均可提高在混响限制条件下的检测能力,提高目标信混比。改善信道多途效应对传统被动测距性能影响,同样也有时间反转镜被动定位技术的用武之地,文中进行了理论分析及仿真研究。第五,矢量水听器时间反转镜被动定位技术研究。海洋传播的声信息既有标量信号,也有矢量信号。声压是标量,振速信号是矢量。单矢量水听器时间反转镜定位处理,可获得二元声压阵时间反转镜定位效果,但其运算量也是单声压水听器的两倍。矢量水听器与时间反转镜联合处理后,单矢量水听器即可实现空间三维定位。二元矢量阵时间反转镜检测能力明显高于单矢量水听器。作为一项新兴的被动定位技术,时间反转镜被动定位技术的研究,国内尚处于起步阶段,作者希望本文能够有助于促进此项技术的深入研究,使这一新技术早日应用到声纳装备上。更多还原

【Abstract】 This paper focuses on the passive localization techniques based on time reversal mirror (TRM), validates the applicability and feasibility of TRM and corresponding algorithms.This paper mainly concentrates on the following problems:First, basic theory, physical and mathematic models, and corresponding processing methods of passive localization based on TRM are studied according to the reciprocity principle of the sound field and ray theory of sound propagation. The feasibility of TRM technique applying to passive localization is proved in theory. It deduces the formulas of TRM and establishes passive localization models of single sensor, two-sensor-array and multi-sensor-array. The study reveals that the matched degree between simulated and actual sound channel determines the passive localization performances of TRM.Second, the paper verifies the correctness of algorithms and codes, and evaluates the performances of TRM passive localization with simulation data processing. The target location is found at the highest power output of TRM by searching over vertical depth and horizontal range. The simulation results indicate that the localization precision reaches the search step of which the minimum is 2 meters in depth and 5 meters in range. The minimum detectable SNR of single sensor may reach to -8dB, and the more sensors are used in TRM processing, the higher the detection performance. The results also conclude that the array gain of TRM is greater than conventional beamforming based on the hypothesis of plane wave.Third, sea-test data processing of vertical array indicates the potential useful value of TRM. The single sound pressure sensor and single vector hydrophone can localize target, and multi-sensor array may detect target in lower SNR. But, it shows that the localization precision of sea-test data is much lower than that of simulation data, so that it puts forwards the new TRM algorithm which is more tolerant and more robust.Fourth, the time reversal mirror technology can be used in several fields of sonar. TRM may focus energy at target position, which may change the disadvantage of multi-path channel into advantage. The lake test verifies that the active or passive time reversal mirror technology can also be used in active sonar and improves signal to reverberation ratio. It also can be used in improving passive ranging performance under the impact of multi-path transmission, which has been studied in theory and tested using simulated data in this paper.Fifth, the paper studies TRM passive localization with vector hydrophone. The oceanic acoustic signal includes sound press signal and vibration signal. The detection performance of single vector hydrophone TRM is as high as that of two sound press sensors, however, its computation is as twice heavy as single sound press sensor. Single vector hydrophone can carry out spatial three-dimension localization.As a newly bora technique, domestic researches on the passive localization by TRM are still at their initial stages. The author hopes this paper will be helpful to the promotion of further studies on the correlative techniques and their applications on sonar and generalizations.更多还原