High-accuracy real-time Doppler estimation is one of the key problems in underwater acoustic communication systems. Using the dual-hyperbolic-frequency-modulation (dual-HFM) synchronous signal is an effective solution; however, the Doppler estimation accuracy is limited by the sampling frequency in the traditional methods. In this letter, we propose a high-accuracy speed spectrum scanning method based on the Doppler invariant and the frequency spectrum properties of the HFM signal. This signal processing system uses dual-HFM waveform as a synchronous signal, constructs the speed spectrum function at the receiver, and then obtains the Doppler estimate through one-dimensional scanning. This method breaks through the speed resolution limit induced by the sampling frequency in the traditional method and obtains a high-accuracy estimate. The influences of signal transmission and processing parameters on the Doppler estimation is analyzed, and the parameter selection criteria is presented to improve the reliability of the estimation. The results of both numerical simulation and underwater communication experiments prove the effectiveness of the proposed method.

中文翻译：

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基于双HFM信号和速度谱扫描的多普勒估计

高精度实时多普勒估计是水声通信系统的关键问题之一。使用双双曲调频（dual-HFM）同步信号是一种有效的解决方案；然而，传统方法中多普勒估计精度受到采样频率的限制。在这封信中，我们提出了一种基于多普勒不变量和HFM信号频谱特性的高精度速度频谱扫描方法。该信号处理系统采用双HFM波形作为同步信号，在接收端构造速度谱函数，然后通过一维扫描得到多普勒估计。该方法突破了传统方法中采样频率引起的速度分辨率限制，获得了高精度的估计。分析了信号传输和处理参数对多普勒估计的影响，提出了参数选择准则，以提高估计的可靠性。数值模拟和水下通信实验结果证明了该方法的有效性。