Frequency estimation of a tonal signal in passive sonar systems is crucial to the identification of the marine object. In the conventional techniques, a basis mismatch error caused by the discretization of the frequency domain is unavoidable, resulting in a severe degradation of the object detection quality. To overcome the basis mismatch error, we propose a tonal frequency estimation technique in the continuous frequency domain. Towards this end, we formulate the frequency estimation problem as an atomic norm minimization problem. From the numerical experiments, we show that the proposed technique is effective in identifying the tonal frequency components of marine objects.

无源声纳系统中音调信号的频率估计对于识别海洋物体至关重要。在传统技术中，不可避免的是由于频域的离散化而导致的基本失配误差，从而导致对象检测质量的严重降低。为了克服基本失配误差，我们提出了一种在连续频域中的音调频率估计技术。为此，我们将频率估计问题表述为原子范数最小化问题。从数值实验中，我们表明，所提出的技术在识别海洋物体的音调频率成分方面是有效的。