卫星结构中的非金属材料

介绍了各种复合材料、胶粘剂、高分子材料和工业陶瓷等非金属材料的性能及其在卫星结构中的应用情况。强调了非金属材料在提高卫星性能、减轻卫星结构质量，以及增大卫星有效栽荷方面的作用。最后指出了卫星结构材料高性能、多功能、复合化、智能化、低成本以及高环境相容性的发展趋势。     

Fade duration statistics for Ku-band satellite links

Fade duration database was built to enhance the study of propagation characterises in the Equatorial region. The data was measured via a beacon receiver Ku-band whereby the antenna was directed to a SUPERBIRD-C2 satellite at 12.255 GHz. The performance of the measured data has been compared with ITU-R model, Kormanyos et al. and Paulson–Gibbins. The results show that the Paulson–Gibbins fits well with measured data with a low RMS error of 0.2 dB. The number of statistics available for the equatorial is small and the periods of measurement are short compared to those for temperate regions.     

Temperature comparison between CHAMP radio occultation and TIMED/SABER measurements in the lower stratosphere

Global Positioning System (GPS) receiver on the CHAllenging Mini-satellite Payload (CHAMP) and the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument, one of four on board the TIMED satellite, provide middle atmosphere temperature profiles by Radio Occultation (RO) and limb viewing infrared emission measurements, respectively. These temperature profiles retrieved by two different techniques in the stratosphere are compared with each other using more than 1300 correlative profiles in March, September and December 2005. The over-all mean differences averaged over 15 and 35 km are approximately −2 K and standard deviation is less than 3 K. Below 20 km of altitude, relatively small mean temperature differences ∼1 K are observed in wide latitudinal range except for June (during the SABER nighttime observation). In the middle to low latitudes, between 30°S and 30°N, the temperature difference increases with height from ∼0–1 K at 15 km, to ∼−4 K at 35 km of altitude. Large temperature differences about −4 to −6 K are observed between 60°S and 30°N and 31–35 km of altitude for all months and between 0° and 30°N below 16 km during June (nighttime).     

高性能飞行器大气数据传感技术研究进展

大气数据是飞行器导航和控制的重要参数，大气数据传感技术是实现飞行器飞行安全及性能发挥的重要保障。针对高性能飞行器对大气数据传感技术的发展需求进行分析，重点介绍了传统大气数据传感技术、嵌入式大气数据传感技术、光学大气数据传感技术及虚拟大气数据传感技术的发展和特点，并对推动嵌入式大气数据传感技术发展的相关技术问题进行了分析和总结，最后对大气数据传感技术的发展进行展望。     

Hypothesis-test-based landcover change detection using multi-temporal satellite images – A comparative study

Remote sensing images and technologies have been widely applied to environmental monitoring, in particular landuse/landcover classification and change detection. However, the uncertainties involved in such applications have not been fully addressed. In this paper two hypothesis-test-based change detection methods, namely the bivariate joint distribution method and the conditional distribution method, are proposed to tackle the uncertainties in change detection by making decisions based on the desired level of significance. Both methods require a data set of class-dependent no-change pixels to form the basis for class-dependent hypothesis test. Using an exemplar study area in central Taiwan, performance of the proposed methods are shown to be significantly superior to two other commonly applied methods (the post-classification comparison and the image differencing methods) in terms of the overall change detection accuracies. The conditional distribution method takes into consideration the correlation between digital numbers of the pre- and post-images and the effect of the known pre-image digital number on the range of the post-image digital number, and therefore yields the highest change detection accuracy. It is also demonstrated that the class-dependent change detection is crucial for accurate landuse/landcover change detection.     

圆轨道星座全球覆盖的充分必要条件

对采用圆轨道的星座，目前的研究基本上局限于实际应用方面，很少进行理论方面的研究，本文首次提出并证明了达到全球连续多重覆盖的充要条件。这对进行星座设计具有积极的指导意义。     

基于实测星载原子钟数据的脉冲星守时方法

利用脉冲星估计星载原子钟钟差是实现卫星自主守时的途径之一。为充分分析基于脉冲星的自主守时系统性能，利用实测的星载原子钟钟差数据和中子星内部组成探测器(neutron star interior composition explorer, NICER)的PSR B1937+21脉冲星的观测数据，对比分析了星载原子钟和脉冲星的误差特性。设计了脉冲星守时系统框架和星载原子钟钟差估计方法。以实测的星载原子钟钟差数据为基础，计算分析了脉冲星守时系统的性能。计算结果表明，若脉冲星的脉冲到达时间（time of arrival, TOA）解算精度为1 μs/30 d，则原子钟钟差估计精度可达到优于1 μs的水平，初步验证了脉冲星守时系统的可行性。     

J2项和大气阻力摄动作用下卫星编队构型的演化分析

研究卫星编队构型在J2项摄动和大气阻力摄动作用下的演化进程。从相对运动动力学模型出发,分别加入J2项摄动和大气阻力摄动因素,采用数值积分对所获得的运动方程求解,得到参考星和环绕星在惯性坐标系中的绝对运动规律;将两星的绝对运动规律作差后,利用坐标转换矩阵,将惯性坐标系中两星的相对运动规律转换到Hill坐标系中。由于该方法没有经过任何简化,故研究摄动的影响时不存在误差。最后通过仿真分析,给出了J2项摄动和大气阻力摄动作用下卫星编队构型演化的相关结论,并提出进一步研究的方向。     

资源三号卫星廊坊地区遥感数据的融合处理

本文以资源三号卫星河北省廊坊地区2A级全色遥感影像和多光谱影像数据为基础,采用遥感数字图像处理软件ERDASIMAGINE进行了研究区域的提取,并对提取的感兴趣区进行了几何校正,即图像配准处理,然后进行了融合处理,分别采用了空间增强的分辨率融合算法、改进IHS分辨率融合算法以及小波分辨率融合算法,通过和融合前的影像进行对比,融合后的影像既保留了多光谱影像的丰富的波谱信息,同时具有了全色影像的高空间分辨率的特征,最后对比三种融合算法,得出改进的IHS分辨率融合算法效果最佳。