Ionospheric phase contamination deteriorates the coherence of high-frequency echoes, reducing the detection performance of multiple-input multiple-output over-the-horizon radar (MIMO-OTHR) on slow ships. A high-precision phase decontamination method approximately extracts a single-frequency reference signal from the echo in advance, called the calibration signal, which is completed in the Doppler domain. When severe ionospheric phase contamination causes the echo Bragg peaks to overlap, this operation is difficult to achieve. To solve this problem, the authors transform calibration signal extraction into a sparse decomposition of a short-time sequence vector set and solve it by an iterative method. This process is based on the sparsity of the short-time sequence in the Doppler domain, as well as the reversibility between the original data vector, accumulated after a long coherence time, and its corresponding short-time sequence vector set, obtained by sliding window segmentation of the original data vector. Then the ionospheric phase contamination is extracted from the calibration signal to compensate for the original echo. Compared with existing methods, the proposed method can adaptively extract a calibration signal to achieve high-precision phase compensation of a MIMO-OTHR echo while adding a more robust performance against noise when considering overlapping Bragg peaks formed by serious ionospheric phase contamination.

中文翻译：

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多输入多输出超视距雷达基于稀疏分解的电离层相位去污

电离层相位污染会破坏高频回波的相干性，从而降低慢船上多输入多输出超视距雷达（MIMO-OTHR）的检测性能。高精度相位去污方法预先从回波中近似提取单频参考信号，称为校准信号，该信号在多普勒域中完成。当严重的电离层相位污染导致回波布拉格峰重叠时，很难实现此操作。为了解决这个问题，作者将校准信号提取转换为短时序列向量集的稀疏分解，并通过迭代方法进行求解。此过程基于多普勒域中短时间序列的稀疏性以及原始数据向量之间的可逆性，在较长的相干时间之后累积的累积量及其对应的短时间序列向量集，通过对原始数据向量进行滑动窗口分割而获得。然后，从校准信号中提取电离层相位污染，以补偿原始回波。与现有方法相比，该方法可以自适应地提取校准信号，以实现MIMO-OTHR回波的高精度相位补偿，同时考虑到严重电离层相位污染形成的重叠布拉格峰时，可以提高抗噪声性能。然后，从校准信号中提取电离层相位污染，以补偿原始回波。与现有方法相比，该方法可以自适应地提取校准信号，以实现MIMO-OTHR回波的高精度相位补偿，同时考虑到严重电离层相位污染形成的重叠布拉格峰时，可以提高抗噪声性能。然后，从校准信号中提取电离层相位污染，以补偿原始回波。与现有方法相比，该方法可以自适应地提取校准信号，以实现MIMO-OTHR回波的高精度相位补偿，同时考虑到严重电离层相位污染形成的重叠布拉格峰时，可以提高抗噪声性能。