高分一号卫星PMS 相机多场地宽动态辐射定标

为克服卫星遥感器常规定标方法不足,实现GF-1 卫星PMS 相机高精度在轨定标,提出了多场地宽动态辐射定标方法,分析了新方法的不确定度。首先,介绍宽动态辐射定标原理和试验场区概况,设计开展了GF-1 卫星多场地同步观测试验;接着,基于试验数据和宽动态定标模型,实现了GF-1 卫星PMS 相机的在轨辐射定标;最后,讨论GF-1 卫星PMS 相机多场地定标的不确定度和模型的稳定性。结果表明:GF-1 卫星PMS 相机自发射以来辐射响应特性与实验室定标结果相比发生了一定变化,最大变化量达到了7.72%;PMS 相机多场地辐射定标的综合不确定度为5.35%。所获取的PMS 相机定标系数满足遥感辐亮度产品生产的精度要求,且多场地定标可作为后续高分卫星的在轨定标的方法参考。     

GF5B热红外通道星上定标与验证

以GF5B卫星发射前实验室定标为基础,采用星上0级黑体定标数据,建立了适用于GF5B热红外通道的星上绝对辐射定标模型。通过对2022年01月12日星上黑体定标数据进行处理,获得成像仪热红外通道的绝对辐射定标系数。对星上定标系统精度进行分析,并采用地面同步烟台浮标数据对定标结果进行精度验证,结果表明,在轨后星上定标系统的绝对定标精度为0.9 K;星地验证结果显示B11和B12通道亮温的偏差分别为0.33、0.77 K。说明基于星上黑体的定标方法具有较好的精度,定标结果可靠,可满足遥感数据定量化应用的需要,为实时准确获取热红外通道定标系数提供了方法借鉴。     

Landsat-5 TM reflective-band absolute radiometric calibration

The Landsat-5 Thematic Mapper (TM) sensor provides the longest running continuous dataset of moderate spatial resolution remote sensing imagery, dating back to its launch in March 1984. Historically, the radiometric calibration procedure for this imagery used the instrument's response to the Internal Calibrator (IC) on a scene-by-scene basis to determine the gain and offset of each detector. Due to observed degradations in the IC, a new procedure was implemented for U.S.-processed data in May 2003. This new calibration procedure is based on a lifetime radiometric calibration model for the instrument's reflective bands (1-5 and 7) and is derived, in part, from the IC response without the related degradation effects and is tied to the cross calibration with the Landsat-7 Enhanced Thematic Mapper Plus. Reflective-band absolute radiometric accuracy of the instrument tends to be on the order of 7% to 10%, based on a variety of calibration methods.     

光学遥感基础实验过程

敦煌辐射校正场,是我国为实现对地观测卫星传感器的辐射校正于１９９６年确定的陆地校正场．校正场实验的目的是准确把握场地的遥感光学特性,用于校正模式模型的建立以及实施卫星传感器的校正的同步观测．校正场实验是光学遥感基础实验过程较为系统和完整的范例之一．     

基于均匀场地的遥感图像相对校正算法研究

受地面均匀场地宽度的限制,使用均匀场地两点相对辐射校正算法,只能对幅宽比较窄的线阵推扫式传感器进行相对校正.提出了一种改进的基于均匀场地的遥感图像相对辐射校正算法,该算法通过在一幅或多幅图像上选取满足亮度要求的区域来计算所选区域内及区域间的相对定标系数,根据区域内和区域间相对定标系数将宽幅线阵推扫式传感器全体探测元的响应相对校正到一致.结果表明:该算法能够实现宽幅线阵推扫式传感器的相对辐射校正,实现简单.校正效果理想.     

利用大洋浮标数据和NCEP再分析资料对FY-2C红外分裂窗通道的绝对辐射定标

介绍利用大洋浮标数据和NCEP再分析资料对FY-2C红外分裂窗通道进行在轨绝对辐射定标的方法,并选择了2006年10个时次的卫星数据进行辐射定标试验.将利用这种方法获得的定标结果与FY-2C卫星数据产品中提供的定标查找表进行比较分析,结果表明两套不同的定标系数反演的大气层顶(TOA)亮度温度的主要差别集中在云顶、冰雪覆盖区域等低温像元;而在常温区的陆表和海表像元定标结果差别较小,反演的TOA亮温差在2K左右.提出的替代定标方法可以极大地提高定标频次,为实现FY-2C红外分裂窗通道的实时绝对辐射定标提供了重要的方法基础.     

敦煌地区气溶胶光学厚度的反演研究

1999年,敦煌遥感卫星辐射校正场开始业务化运行。随着敦煌的城市建设和经济发展,辐射校正场周边环境发生较大的变化。为了了解辐射场的气溶胶光学厚度变化情况,2013年6月至7月,中国资源卫星应用中心在敦煌地区进行了为期15天的野外观测实验,采用法国CMEL公司研制的太阳分光光度计CE318对敦煌地区的大气进行测量,获得了4天晴空的大气光学数据。反演结果表明敦煌遥感卫星辐射校正场的气溶胶光学厚度日变化和逐日变化情况不大,550 nm处的光学厚度均值在0.3左右,符合遥感卫星辐射定标大气条件。     

星上红外遥感相机的辐射定标技术发展综述

随着对天基对地以及临近空间目标探测的需求增大,高性能红外相机探测及海量数据定量化迫切需要高可靠性、高精度的辐射定标技术,因此,星上辐射定标装置已成为当前空间定量遥感技术发展的重要方向。在轨红外遥感相机的辐射定标主要校正探测器响应的不均匀性（相对辐射定标）和建立遥感相机输出信号与输入辐射量的函数关系（绝对辐射定标）。在介绍红外相机星上辐射定标基本原理的基础上,综述近年来几个国内外典型星上辐射定标装置及其特点,并介绍笔者所在课题组近年来基于内部定标源+天空星图的红外相机高动态范围（HDR）相对辐射定标方法的研究进展。论文对于红外辐射定标技术及星上辐射定标装置的发展具有参考意义。     

CBERS-2 CCD相机绝对辐射定标系数验证与评价

卫星遥感器绝对辐射定标系数的有效性检验，是对卫星遥感精度进行全面评价的最有效手段之一。利用绝对辐射定标系数反演反射率值与实测值对比的方法，对CBERS-2CCD相机绝对辐射定标结果进行了有效性检验与误差分析，根据分析结果对CCD相机4个波段的绝对辐射定标系数作出了客观的评价。验证表明，两点法获得的CCD相机定标系数可靠，定标效果较好，而单点法获得的定标系数对CCD相机不适用。     

红外相机实时绝对辐射定标技术研究

辐射定标技术是实现定量遥感的关键环节。近年来,随着红外遥测技术愈发成熟,星上红外辐射定标已成为空间定量遥感技术的重要发展方向。文中从红外相机实时绝对辐射定标的背景出发,提出了半光路星上绝对辐射定标和基于多温度场的场地绝对辐射定标方法,结合实验数据,分别采用星上定标、场地定标、交叉定标三种方案进行在轨绝对辐射定标实验验证,并对其适用场景进行了分析。结果表明,通过结合半、全光路定标数据处理和转换技术,利用水面场和陆面场的场地绝对辐射定标方法,优选合适的定标场地,同时在陆面场中增加典型地物场景实现多温度场定标的方法,所提出的辐射定标方法实现了实时高精度绝对辐射定标,定标精度优于1.5 K。     

新型智能温度传感器在辐亮度标准探测器温控系统中的应用

高精度辐射定标方法和技术是现代空间遥感的主要支撑技术之一.辐亮度标准探测器是新一代高精度辐射定标方法中的核心部件,在遥感仪器的野外、机载和星上高精度辐射定标中具有广阔的应用前景.但是,温度变化是影响辐亮度标准探测器绝对精度和长期稳定性的一项关键因素,只有加入温控系统,将其控制在恒定的工作温度,才能使它的精度和稳定性得以保证.结合数字温度传感器DS18B20在辐亮度标准探测器精密温控系统中的应用经验,提出了采用DS18B20实现标准探测器温度高精度、高可靠性监测和控制的有效方案.实验结果证明,该方案是可靠和可行的.     

Potential of Getis statistics to characterize the radiometric uniformity and stability of test sites used for the calibration of Earth observation sensors

The calibration of airborne and satellite remote sensing sensors is a fundamental step for the rigorous validation of products derived from satellite data. Because of the inaccessibility of Earth Observation Satellites on orbit, the direct calibration method based on a test site with ground reference data is often considered necessary. However, the problem of radiometric spatial uniformity and temporal stability of test sites constitutes an important issue in the accuracy achieved in calibration operations and the long-term characterization of satellite sensor radiometry. Generally, the coefficient of variation and semivariograms are the most widely used tools for evaluating the radiometric uniformity and stability of a calibration site. In this study, we analyze for the first time the potential of Getis statistics compared to the coefficient of variation for the study of the radiometric spatial uniformity and temporal stability of the Lunar Lake Playa, Nevada (LLPN) test site. The results obtained show the potential and the importance of the synergy generated by these two methods for analyzing the radiometric temporal stability of the LLPN site. Getis statistics provide an excellent spatial analysis of the site while the coefficient of variation provides complementary information on the temporal evolution of the site.     

Evaluation and Comparison of the IRS-P6 and the Landsat Sensors

The Indian Remote Sensing Satellite (IRS-P6), also called ResourceSat-1, was launched in a polar sun-synchronous orbit on October 17, 2003. It carries three sensors: the high-resolution Linear Imaging Self-Scanner (LISS-IV), the medium-resolution Linear Imaging Self-Scanner (LISS-III), and the Advanced Wide-Field Sensor (AWiFS). These three sensors provide images of different resolutions and coverage. To understand the absolute radiometric calibration accuracy of IRS-P6 AWiFS and LISS-III sensors, image pairs from these sensors were compared to images from the Landsat-5 Thematic Mapper (TM) and Landsat-7 Enhanced TM Plus (ETM+) sensors. The approach involves calibration of surface observations based on image statistics from areas observed nearly simultaneously by the two sensors. This paper also evaluated the viability of data from these next-generation imagers for use in creating three National Land Cover Dataset (NLCD) products: land cover, percent tree canopy, and percent impervious surface. Individual products were consistent with previous studies but had slightly lower overall accuracies as compared to data from the Landsat sensors.     

成像光谱仪辐射定标概览

成像光谱仪相关技术研究一直是遥感技术研究前沿,成像光谱仪完善的辐射定标是完成各种高质量定量化产品应用的基础.本文介绍了成像光谱仪辐射定标原理和辐射定标方法,并对成像光谱仪辐射定标技术进行了展望.     

星载大气痕量气体差分吸收光谱仪数据的定标处理与存储方式研究

星载大气痕量气体差分吸收光谱仪搭载于太阳同步轨道卫星,用于获取紫外至可见波段的高光谱遥感数据,可定量监测全球痕量气体分布、变化及输运过程。为满足大量实时遥感数据的读写功能,并实现载荷数据的快速有效查找与读取要求,选择HDF5数据格式存储大气痕量气体差分吸收光谱仪获得的遥感数据。为测试数据的有效性,基于载荷在实验室获取的0级测试数据,通过暗背景扣除、增益修正、光谱定标与辐射定标等处理,获得1级遥感数据,并将其成功写入HDF5文件中,从而为载荷入轨后的处理提供数据支持。     

利用南海水面开展我国静止气象卫星红外通道在轨辐射定标

中国遥感卫星辐射校正场以青海湖水面作为遥感卫星红外探测通道外场辐射定标的场地.我国静止气象卫星风云二号(FY-2)系列是自旋稳定卫星,其红外通道无法进行在轨时的星上绝对定标,而青海湖对于位于东经105°赤道上空的FY-2卫星来说,卫星天顶角有36°,超过了外场辐射校正测量规范要求.本文介绍了利用我国南海海面水体辐射,进行与静止气象卫星的同步测量试验,开展卫星红外通道在轨外场辐射定标处理的可行性研究.在分别对FY-2B与FY-2C的测量数据处理后,初步确定我国南海海面可以作为我国静止气象卫星在轨辐射定标的场地.     

高精度中远红外辐射定标技术研究

红外辐射定标是红外遥感信息定量化的关键技术之一。从我国空间红外传感器的发展要求出发，结合国外基于绝对低温辐射计的红外辐射定标技术研究状况，提出了利用宽波段可调谐激光器和球状InSb、HgCdTe光电探测器以及薄膜热电堆探测器TS-76来实现高精度中远红外辐射定标的技术方案。     

Parameter trade-offs for imaging spectroscopy systems [remotesensing]

To help better understand the problems of specifying data acquisition parameters and extracting desired information from the voluminous data, research has been focused on understanding the remote sensing process as a system and investigating the interrelated effects of various parameters. A system model is used to explore system parameter trade-offs for a model sensor based on the High-Resolution Imaging Spectrometer (HIRIS). Radiometric performance was studied, along with the effect on classification accuracy of several system parameters. The atmosphere and sensor have significant effects on the mean received signal and noise performance. The effect of random uncorrelated errors in the radiometric calibration of the detector array is discussed. Accurate pixel-to-pixel relative radiometric calibration and the use of the image motion compensation (IMC) option are seen to improve classification accuracy. The selection of feature sets based on combining spectral bands was studied under a variety of observational conditions     

超连续激光单色仪系统级光谱响应度定标比对验证

细分光谱扫描定标技术是实现遥感器高精度光谱辐射定标的重要方式,基于超连续激光单色仪的定标装置是实现遥感器细分扫描定标的新选择。为验证所建立的超连续激光单色仪装置的系统级定标能力,利用硅辐亮度计和滤光片辐射计,分别采用超连续激光单色仪定标装置和可调谐激光定标装置对其进行了系统级绝对光谱响应度定标比对验证。实验结果表明:在所验证波段范围内,两种定标装置获得的硅辐亮度计绝对光谱响应度系统级定标结果最大偏差为0.6%。通道式滤光片辐射计的带内绝对光谱响应度定标结果最大偏差优于0.4%,带内积分响应度最大偏差约0.1%。文中的研究验证了超连续激光单色仪定标装置具有良好的系统级定标能力,能够获得较高的定标精度,在遥感器的绝对光谱响应度定标中具有重要应用前景。     

Landsat-5 TM and Landsat-7 ETM+ absolute radiometric calibration using the reflectance-based method

The reflectance-based method of vicarious calibration has been used for the absolute radiometric calibration of the Landsat series of sensors since the launch of Landsat-4. The reflectance-based method relies on ground-based measurements of the surface reflectance and atmospheric conditions at a selected test site nearly coincident with the imaging of that site by the sensor of interest. The results of this approach are presented here for Landsat-5 Thematic Mapper (TM) and Landsat-7 Enhanced Thematic Mapper Plus (ETM+). The data have been collected by two groups, one from the University of Arizona and the other from South Dakota State University. The test sites used by the University of Arizona group for this work are the Railroad Valley Playa, Lunar Lake Playa, and Roach Lake Playa all of which are in Nevada, Ivanpah Playa in California, and White Sands Missile Range, New Mexico. The test site for the South Dakota State group is a grass site in Brookings, SD. The gains derived from dates using these sites spanning the period from 1984 to 2003 are presented for TM and for the period of 1999 to 2003 for ETM+. Differences between the two groups are less than the combined uncertainties of the methods, and the data are thus treated as a single dataset. The results of these vicarious data indicate that there has been no degradation apparent in TM since 1995 and in ETM+ since launch. Agreement between the reflectance-based results and the preflight calibration of ETM+ is better than 4% in all bands, and the standard deviation of the average difference indicates a precision of the reflectance-based method on the order of 3%.