定标星

在CCD小视场观测情况下时常难以找到足够数量的定标星。

Also , it is difficult to find sufficient reference stars in the small viewing field of a single CCD observation .

CCD用于建立惯性坐标系（Ⅰ）测定河外星系与定标星的相对位置

To Build Up the Inertial Coordinate System With A CCD (ⅰ) Measuring the Relative Position of An Extragalactic System with Respect to the Reference Stars

利用的定标星越多，计算的精确度就越高。

The calculation becomes more accurate if more reference stars are used .

在常规照相天体测量工作中，对暗天体的定位是采用逐级定标星过渡的方法实现的。

In the routine photographic astrometry , the position determination of faint celestial body is realized by using multi-step transition of reference stars .

本文详细讨论了在测定河外星系与定标星的相对位置中的误差累积效应，并给出了相应的数值估计。

In this paper , the effects of error accumulation in determining the relative positions of galaxies with respect to the reference stars are discussed in detail and the corresponding numerical estimates are also made .

天线方向图的准确测量，对星载SAR图像的应用具有重要作用。分布目标辐射定标在星载SAR天线方向图测试中受到广泛重视。

Accurate measurement of antenna pattern is important to spaceborne SAR image application , and distributed target antenna pattern measurement is widely concerned .

结果表明利用辐射校正场辐射定标与星上定标相差5%左右，相当于3K的亮温差。

The result show the difference between in flight and on board calibration is about 5 % , equivalent to a brightness temperature of 3 K.

为了标定试验设备空间位置，研制了一种像面位置可调的定焦距标星电视系统。

In order to determine the position of the theodolite , a star-observing TV system with adjustable image position and fixed focal length was developed .

天线外定标是实现星载SAR天线方向图在轨测试的主要手段。

External calibration is key method used for spaceborne SAR antenna onboard measurement .

随着合成孔径雷达（SAR）图像定量应用的日益广泛和深入，定标已成为现代星载SAR遥感测量的必备技术条件。

With the increasingly extensive and in-depth application of quantitative Synthetic Aperture Radar ( SAR ) images , SAR calibration became a necessary technique in modern spaceborne SAR remote sensing .

空间环境监测器在整个研制过程中都离不开测试环节，其测试系统是研制阶段的必要设备，为探测器的开发、研制、测试、调试、定标过程以及装星测试提供系统支持手段。

Tests are needed during the whole research and development process of space environment monitor . The test system is the necessary equipment and can support the research , development , testing , debugging , calibration process .