Ship targets are high-value military and civilian targets with broad application prospects. However, the precise focusing of ships is still a difficult issue because of their complicated six-degree-of-freedom motions on the sea surface. This paper focused on investigating the effect of ship six-degree-of-freedom oscillation on Synthetic Aperture Radar imaging. Firstly, based on the six-degree-of-freedom motions, the accurate range models for ship linear oscillation and angular oscillation were built, and the superiority was verified by comparing them with the models described in published literature. Secondly, we used the Taylor formula and Bessel function to expand the phase error introduced by ship oscillation, then their effects on imaging were further analyzed. Finally, based on the measured ship attitude data, we generated the semi-physical echoes of the oscillatory ship to validate the analysis throughout this article. Based on the proposed range model, we also made some tentative on the phase compensation method by fitting ship attitude angles with multiple sinusoidal functions.

中文翻译：

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舰船目标六自由度振荡对SAR成像的影响

船舶目标是具有广泛应用前景的高价值军事和民用目标。然而，由于船舶在海面上的复杂的六自由度运动，船舶的精确聚焦仍然是一个难题。本文重点研究舰船六自由度振荡对合成孔径雷达成像的影响。首先，基于六自由度运动，建立了船舶线性振荡和角振荡的精确距离模型，并将其与已公开文献中描述的模型进行了比较，验证了其优越性。其次，我们利用泰勒公式和贝塞尔函数扩展了船舶振荡引入的相位误差，然后进一步分析了它们对成像的影响。最后，根据测得的船舶姿态数据，我们生成了振荡船的半物理回波，以验证本文中的分析。在提出的距离模型的基础上，我们还通过对具有多个正弦函数的船舶姿态角进行拟合，对相位补偿方法进行了一些尝试。