Magnetron-based marine radar technology is mature, affordable, reliable, and very effective for maritime safety applications. Commercial systems may be procured at a modest cost as compared to fully coherent solid-state systems. Magnetron oscillators inherently generate random phase signals. Phase instability on a pulse-to-pulse basis impedes this class of marine radars from success in applications requiring coherency such as moving target indication (MTI) or in generating target imagery. This limitation may be overcome by incorporating radio frequency sampling and cross-correlation of the transmit and receive signal technology to augment the current capability of available systems. In this research, the pulse train on transmit and receive is correlated in order to reject interference and detect image targets. Sampling the transmit signal and target echo on receive permits fully coherent processing. Marine radars traditionally operate non-coherently, and as such, offer limited surveillance in clutter rich environments. In this study, the authors report on a non-coherent marine radar that has been modified to produce a pseudo-coherent or coherent-on-receive sensor system. This is crucial to MTI and target image formation. In laboratory experiments, they employed a magnetron oscillator-based system to generate an inverse synthetic aperture radar image. The image was formed using four different algorithms: filtered back-projection (FBP), time domain back-projection (TDBP), an algebraic reconstruction technique, and frequency domain back-projection. In their research, TDBP produces exquisite imagery of steel rods, and it is the standard developed in this study. FBP performed poorly as compared to all other algorithms.

中文翻译：

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使用伪相干海洋雷达技术进行雷达成像

基于磁控管的船用雷达技术已经成熟，价格合理，可靠，并且对于海上安全应用非常有效。与完全相干的固态系统相比，可以以适度的成本购买商用系统。磁控振荡器固有地产生随机相位信号。脉冲间的相位不稳定性阻碍了这类海洋雷达在需要相干性的应用（例如移动目标指示（MTI））或生成目标图像方面的成功。通过结合射频采样以及发射和接收信号技术的互相关性来增强可用系统的当前能力，可以克服此限制。在这项研究中，发射和接收上的脉冲序列相互关联，以消除干扰并检测图像目标。在接收时对发射信号和目标回波进行采样可以实现完全相干的处理。航海雷达传统上是非相干运行的，因此，在杂乱的环境中提供有限的监视。在这项研究中，作者报告了一种非相干海事雷达，该雷达已被修改以产生伪相干或接收时相干传感器系统。这对于MTI和目标图像形成至关重要。在实验室实验中，他们采用了基于磁控振荡器的系统来生成反合成孔径雷达图像。使用四种不同的算法形成图像：滤波反投影（FBP），时域反投影（TDBP），代数重构技术和频域反投影。在他们的研究中，TDBP可以绘制出精美的钢棒图像，这是本研究开发的标准。与所有其他算法相比，FBP性能较差。