Department of Electrical and Computer Engineering, Portland State University, Portland, Oregon 97201, USA.
Metron Inc., 2020 SW 4th Avenue, Suite 170, Portland, Oregon 97201, USA.
J Acoust Soc Am. 2019 Sep;146(3):1824. doi: 10.1121/1.5126520.
In recent years, methods have been developed to estimate a variety of environmental parameters based on measurements of the ocean ambient noise. For example, noise has been used to estimate water depth using the passive fathometer technique and bottom loss estimated and used to invert for seabed parameters. There is also information in the noise about the water column sound speed, volume attenuation, and the sea-state. The Fisher information can be used to quantify the basic information available in the noise measurements and its inverse, the Cramér-Rao lower bound (CRLB), provides the lower limit on the variance of an unbiased estimator of a particular parameter. The CRLB can be used to study the feasibility of various measurement configurations and parameter sensitivities. In this paper, the CRLB is developed for ocean ambient noise and the environmental information contained in the measurements is determined. The CRLBs provide an estimate of the underlying information in the data, however, it is independent of the estimation methodology. This is useful to determine if a given estimation method is reaching the lower bound. Results illustrating the bounds as well as sensitivities and performance of estimators are demonstrated using both simulations and data.
近年来，已经开发出了多种方法，可基于对海洋环境噪声的测量来估计各种环境参数。例如，已经使用噪声通过被动测深技术来估计水深，并且估计和使用底部损耗来反演海底参数。噪声中还包含有关水柱声速、体积衰减和海况的信息。Fisher 信息可用于量化噪声测量中的基本信息量，其逆，Cramér-Rao 下限（CRLB），为特定参数的无偏估计量的方差提供了下限。CRLB 可用于研究各种测量配置和参数灵敏度的可行性。本文为海洋环境噪声推导了 CRLB，并确定了测量中包含的环境信息。CRLB 提供了数据中基础信息的估计，但它与估计方法无关。这对于确定给定的估计方法是否达到下限很有用。结果使用模拟和数据演示了边界以及估计器的灵敏度和性能。
