Decimetre Level Range Resolution for Beidou B3I Signal-Based Passive SAR Imaging—Proof-of-Concept Experimental Demonstrations
Decimetre Level Range Resolution for Beidou B3I Signal-Based Passive SAR Imaging—Proof-of-Concept Experimental Demonstrations
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DOI：
10.1109/access.2021.3056666
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发表时间：
2021
期刊：
影响因子：
3.9
通讯作者：
Yu Zheng;Zhuxian Zhang;Peng Wu;Peidong Zhu
中科院分区：
文献类型：
--
作者：
Yu Zheng;Zhuxian Zhang;Peng Wu;Peidong Zhu
新一代全球导航卫星系统--北斗B3卫星系统的建设已在全球范围内完成，但各自的实施研究仍处于起步阶段。因此，开展基于北斗B3I信号的无源合成孔径雷达的研究，对于推动北斗技术的快速发展具有十分重要的意义。提出了北斗B3I合成孔径雷达分米级距离分辨率成像方法。为了在距离域分离混叠反射B3I信号，我们提出了级联二阶微分算子(Diff2)和级联Teager-Kaiser(TK)算子，并将它们分别应用于存在距离压缩脉冲的区域。之后，为了消除由所提出的算子带来的明显的旁瓣，采用了零阈值方案。为了获得具有分米距离分辨率的最终距离压缩信号，对相应的零阈值脉冲进行相位恢复。为了验证所提方法的有效性，用北斗B3I信号原始数据进行了概念验证仿真和实验对比。结果表明，北斗B3I-SAR的距离压缩脉冲主瓣宽度确实可以达到0.4m量级，与目前无源GNSS合成孔径雷达的米级距离分辨率相比，该方法可以达到分米级的距离分辨率。同时，在比较基于级联Diff2算子和级联TK算子的方法时，由于级联TK算子和级联Diff2算子各自对背景区域的干扰程度较小，因此后者是在外部执行的。
The construction of the Beidou B3 satellite system, a new-generation global navigation satellite system, has been completed worldwide, however the respective implementation studies remain in the start-up stage. Accordingly, studies of passive Beidou B3I signal-based synthetic aperture radar (Beidou B3I-SAR) are very meaningful in terms of promoting the rapid development of the Beidou technique. This paper proposes methods for Beidou B3I SAR imaging of decimetre level range resolution. To separate aliased reflected B3I signals at range domain, we presented cascaded secondary order differentiation operator (Diff2) and cascaded Teager-Kaiser (TK) operator, applied them to the regions where exists range compressed pulses, respectively. Thereafter to eliminate the obvious side-lobes which brought by the proposed operators and with the values less than zero, zero thresholding scheme is employed. To obtain the final range compressed signals with decimetre range resolution, phase recovery component is performed to the respective zero thresholded pulses. To validate the proposed methods, both proof of concept simulation and the experiment with field Beidou B3I signal raw data are carried out for comparison. The results show that indeed main-lobe width of range compressed pulse can reach the level 0.4 m. This reveals that decimetre level range resolution can be achieved for Beidou B3I-SAR on the basis of proposed methods, in contrast to the current best result of meters level in passive GNSS-based SAR related studies. Meanwhile, in a comparison of the proposed methods on the basis of cascaded Diff2 operator and cascaded TK operator, the later is outer-performed, since the respective brought interference level in background region is less.