Search domain dimension expansion of robust matched-field source radiated power estimation

Compared with the traditional source radiated power estimation method, the matched-field source radiated power estimation method can obtain more accurate estimation results. However, its performance is greatly influenced by environmental mismatch. This paper defines the impact factor of environmental mismatch to quantify the impact of environmental mismatch on the acoustic transfer function and the matched-field source radiated power estimation method. It determines that the key to improve the robustness of environmental mismatch is to accurately estimate the acoustic transfer function. In the traditional matched-field source radiated power estimation method, the search domain of the acoustic transfer function is a distance-depth two-dimensional plane and does not contain the true acoustic transfer function when the environment is mismatched. Therefore, the estimation results of the acoustic transfer function are bound to deviate from those of the true acoustic transfer function. The paper expands the search domain dimension to a three-dimensional search domain that contains distance, depth and uncertain parameter sets. The true acoustic transfer function is included in the search domain. Thus the optimal alternative acoustic transfer function is equal to the true acoustic transfer function. The objective function for the three-dimensional search domain is constructed. The smaller the absolute value of the objective function, the less the acoustic transfer function estimation deviates from the true acoustic transfer function. The source radiated power is estimated more accurately when the alternative acoustic transfer function estimation corresponding to the minimum absolute value of the objective function. The simulation results verify the theoretical analysis results. 与传统声源辐射功率估计方法相比, 匹配场声源辐射功率估计方法能获得更准确的估计结果, 但环境失配对其性能影响较大。针对这一问题, 提出一种搜索域维度扩展稳健匹配场声源辐射功率估计方法。定义环境失配影响因子, 量化表示环境失配对信道传递函数和匹配场声源辐射功率估计方法的影响, 确定提升环境失配稳健性的关键在于准确估计信道传递函数。传统匹配场声源辐射功率估计方法中信道传递函数搜索域是一个距离-深度二维平面, 环境失配时, 其中必然不包含真实信道传递函数, 因此信道传递函数估计结果与真实信道传递函数也必然存在偏差。文中提出的搜索域维度扩展稳健匹配场声源辐射功率估计方法将信道传递函数搜索域扩展为距离、深度和不确定参数组构成的三维搜索空间, 将真实信道传递函数包含在搜索域中, 使得最优备选信道传递函数等于真实信道传递函数。随后构造三维搜索空间的目标函数, 目标函数的绝对值越小, 备选信道传递函数与真实信道传递函数偏差越小。使用目标函数绝对值取最小值时对应的备选信道传递函数可以更准确地估计声源辐射功率, 仿真验证了理论分析的结果。