超短基线水声定位系统相位差解模糊算法研究

基于窄带信号的超短基线水声定位系统通常面临相位差模糊与定位精度之间的矛盾.针对信号频率较高时难以构造传统解模糊方法所需的小于信号半波长阵元间距的问题，提出了一种基于广义最大似然准则的相位差解模糊算法.该算法通过模糊数向量初始化将解模糊问题转化为多元复合假设检验问题，并采用广义最大似然准则判决，进而估计信号方向.该算法无需构造小于半波长的阵元间距，有效扩大了无模糊阵列孔径，且对阵元布放方式要求较低；充分利用了相位差观测数据的统计特性，测向精度接近克拉美-罗界.仿真结果验证了该算法的有效性.

Phase-Difference Ambiguity Resolution for USBL Underwater Acoustic Positioning Systems

Ultra-short baseline (USBL) underwater acoustic positioning systems utilizing narrow band signals are always confronted with the contradiction between phase-difference ambiguity and positioning accuracy.When the signal frequency is high,it is difficult to construct an array with an interval less than a half-wavelength which is always employed in traditional ambiguity resolution technique.Aiming at this problem,a phase-difference ambiguity resolution method based on the generalized maximum likelihood (GML) rule is proposed.Firstly,with vectors of the ambiguity integers initialized,the ambiguity resolution problem is formulated as problem of multiple composite hypothesis testing.Then decision can be made through the GML rule and direction of arrival is obtained.With inter-sensor spacing exceeding half the wavelength,the proposed method effectively extends the unambiguous array aperture and constraint on array configuration is easy to be met.Additionally,under full consideration of the statistical characteristics of observation data,accuracy of direction estimation approaches the Cramer-Rao bound.Simulation results verify the effectiveness of the proposed method.