Key Laboratory of Underwater Acoustic Signal Processing of Ministry of Education, Southeast University, Nanjing 210096, China.
Sensors (Basel). 2018 Aug 24;18(9):2794. doi: 10.3390/s18092794.
In active sonar systems, the target echoes are usually equivalent to a superposition of the Doppler-scaled reflections from multiple highlights. The reflections overlap with each other both in the time and frequency domain, which results in a decreased velocity estimation performance. Recently, the hyperbolic-frequency modulated signal has been widely employed in sonar systems for moving targets due to its Doppler tolerance, while the precise velocity estimation becomes a great challenge under such conditions. In this paper, the echo c is modeled onsidering a target with a constant velocity and multi-highlights. The velocity estimation performance is analyzed though the signal's matched filter and the wideband ambiguity function. An improved method based on the sliding window matching algorithm is proposed to improve the performance. The method controls the energy of environmental noise and interference by focusing on the dominant target highlight, and applying a designed window which utilizes the Doppler characteristics of hyperbolic-frequency modulated signals. Simulations and lake experiment allow us to compare between the improved method and the conventional matched filter method. The results verify the influence of the multi-highlights in velocity estimation and indicate that the improved method has more effective performance.
在主动声纳系统中，目标回波通常等效于多个亮点的多普勒缩放反射的叠加。在时域和频域中，这些反射相互重叠，导致速度估计性能下降。最近，由于具有多普勒容忍度，双曲调频信号已在声纳系统中得到广泛应用，用于移动目标，而在这种情况下，精确的速度估计成为一个巨大的挑战。本文考虑了一个具有恒定速度和多个亮点的目标，对回波 c 进行建模。通过信号的匹配滤波器和宽带模糊函数分析了速度估计性能。提出了一种基于滑动窗口匹配算法的改进方法来提高性能。该方法通过聚焦主导目标亮点并应用利用双曲调频信号多普勒特性的设计窗口，控制环境噪声和干扰的能量。仿真和湖泊实验允许我们比较改进的方法和传统的匹配滤波器方法。结果验证了多亮点对速度估计的影响，并表明改进的方法具有更好的性能。
