天文学进展
天文學進展
천문학진전
PROGRESS IN ASTRONOMY
2014年
1期
24-39
,共16页
小行星%地基雷达探测%延迟多普勒图像%形状模型
小行星%地基雷達探測%延遲多普勒圖像%形狀模型
소행성%지기뢰체탐측%연지다보륵도상%형상모형
asteroids%ground-based radar detection%delay-Doppler image%shape model
地基雷达探测是研究太阳系中小行星的重要方法。雷达探测主要有两种方式：(1)连续波探测，可得到小行星表面的粗糙度等参数；(2)延迟多普勒探测，用于反演小行星的三维形状模型并确定自转轴状态。与其他探测方法相比，雷达观测具有分辨率高等优势。简要介绍了地基雷达探测的原理和方式，以及通过雷达成像建立小行星形状模型的方法。同时举例说明了雷达探测小行星的成果，并对包括雷达在内的多种探测方法进行了比较。
地基雷達探測是研究太暘繫中小行星的重要方法。雷達探測主要有兩種方式：(1)連續波探測，可得到小行星錶麵的粗糙度等參數；(2)延遲多普勒探測，用于反縯小行星的三維形狀模型併確定自轉軸狀態。與其他探測方法相比，雷達觀測具有分辨率高等優勢。簡要介紹瞭地基雷達探測的原理和方式，以及通過雷達成像建立小行星形狀模型的方法。同時舉例說明瞭雷達探測小行星的成果，併對包括雷達在內的多種探測方法進行瞭比較。
지기뢰체탐측시연구태양계중소행성적중요방법。뢰체탐측주요유량충방식：(1)련속파탐측，가득도소행성표면적조조도등삼수；(2)연지다보륵탐측，용우반연소행성적삼유형상모형병학정자전축상태。여기타탐측방법상비，뢰체관측구유분변솔고등우세。간요개소료지기뢰체탐측적원리화방식，이급통과뢰체성상건립소행성형상모형적방법。동시거례설명료뢰체탐측소행성적성과，병대포괄뢰체재내적다충탐측방법진행료비교。
Ground-based radar detection may act as a powerful means to determine the shape and physical properties of the asteroids in our Solar system. By measuring time delay and doppler frequency of the received echoes, radar systems provide information in ranging and radial velocity of the asteroids. Over the past few decades, more than 500 asteroids (mostly near-Earth ob jects) were detected using radar observations. <br> There are two categories of radar detection: (1) The continuous wave detection, which is adopted to determine the roughness of an asteroid’s surface. (2) The delay-Doppler de-tection,which is likely to produce its three-dimensional model, and to define the rotational state. In the delay-Doppler detection, target asteroids are resolved in line-of-sight distance and line-of-sight velocity, providing two-dimensional images with spatial resolution as fine as meter-scale. <br> Besides radar detection, several other techniques would also provide the shape model of the asteroids, among which the lightcurve inverse method is the most popular one to do that. In comparison with other methods, radar observation may have an advantage on spacial resolution. The lightcurves cannot reveal elaborate information on small features, and the intermediate-scale features of the inversed model are only suggestive. By contrast, radar detection produces resolved images. <br> In this review, we present the radar observation technique and the method for recon-structing three-dimensional models of asteroids from radar measurements. In addition, we also provide several examples of asteroid models by radar detection, and then compare them with other observations for the shape reconstruction for the asteroids.
