一种基于天基的瞬变电磁高分辨探测小尺度太空碎片的方法

目前，太空碎片的天基探测方法一般是激光雷达法.由于激光雷达的辐射频率一般为可见光或红外波段，在分辨厘米量级的太空碎片时具有一定的优势.但激光雷达在探测时也面临一些客观问题：即（1）难以捕捉快速移动的太空碎片；（2）对目标体穿透能力低；（3）外层空间的强干扰环境对激光雷达的不良影响等.这些问题在一定程度上限制了激光雷达在太空碎片探测方面的应用.本文针对太空碎片体积小、预警距离远和强干扰环境等特点，提出使用高性能瞬变电磁辐射源对远距离、小尺度的太空碎片进行探测.通过三维矢量有限元方法，分析了利用高性能瞬变电磁辐射源的优点，对比不同瞬变电磁辐射源的幅频特性，从发射机理上证明高性能瞬变电磁辐射源在辐射能力与频率带宽方面都优于传统瞬变电磁辐射源.并通过调整脉冲宽度，得到最适合探测本文太空碎片模型的辐射脉冲.最后通过电场分布图和多测道图对太空碎片的明显电场分异结果，证实了高性能瞬变电磁辐射源在探测远距离、小尺度太空碎片方面的有效性.

A new method for space-based detecting small-scale space debris with high-resolution using transient electromagnetism

Currently, the common method to detect space debris is using laser radar which can locate long-range and small-sized space debris in outer-space. As a traditional method of detecting space debris using space-based radiation source, there are some issues need to be addressed:(1) The laser radar has difficulties to capture fast-moving space debris; (2) laser radars cannot penetrate the object; and (3) due to the strong solar radiation in outer space, the laser radar might be severely disturbed. These problems limit the application of laser radars in outer space. Transient electromagnetic radiation sources have been widely used as a broadband, multi-scale and multi-depth detection source in geophysics. However, such sources need to enhance the radiation capability of radiation sources for the purpose of detecting long-range space debris.#br#In this paper, focusing on the small volume and long detection distance of space debris, we present a high-performance transient electromagnetic radiation source to solve these problems. Due to the fact that the radiation of the transient electromagnetic radiation source cannot utilize the radiation energy efficiently, even if the harmonic components of the radiation pulse satisfy the detection requirement, it is impossible to detect the target body of long-distance and small-scale space debris because of the limitation of the radiation power of the radiation source. In the past, in order to increase the radiation power, the transient electromagnetic radiation source generally needs to increase the size of the radiation source, which is not conducive to the portable detection. The 3D vector finite-element numerical simulation method is used to analyze the characteristics of the high-performance transient electromagnetic source. Firstly, we discuss the radiation characteristics and capabilities of the high-performance transient electromagnetic radiation source, which proves from the transmitting mechanism that the high-performance transient electromagnetic radiation source is superior to the traditional transient electromagnetic radiation source in terms of radiation capability and frequency bandwidth. Secondly, beginning from optimizing the radiation mode of the source, we select a pulse (500 ns) which is most suitable for detecting small-scale space debris in this section. While improving the power of transient electromagnetic radiation, the resolving power of the transient electromagnetic field is further optimized. Thirdly, we analyze the multi-channel responses and resolve the spacing of blocking space debris. Since the space debris is far away from the radiation source and is obstructed by other space debris, when the spacing between the space debris is increased to 500 m, there is a clear electric field differentiation in the multi-channel image.#br#Finally, we introduce a high-performance transient electromagnetic radiation source based on the simulation results of 3D vector finite element. From the simulation results, the high-performance transient electromagnetic radiation source not only can solve the output power of the radiation source, but also greatly reduces the space size of the radiation source, which permits to detect long-distance and small-scale space debris. It also provides another choice for Chinese space-based detection of long-distance and small-scale space debris.