基于ESPRIT算法的极化干涉SAR植被高度反演研究

由于存在着去相干分量,利用ESPRIT(旋转不变技术)算法对植被区域的极化干涉SAR(PollnSAR)数据进行反演的结果有较严重偏差.针对这一问题,结合极化干涉相干最优理论及其物理散射机制,引入新的散射矢量——相干最优化散射矢量,提出一种改进的基于ESPRIT的植被高度反算法.最后,利用欧空局(ESA)提供的模拟L波...     

基于最小二乘配置法的BP神经网络GPS高呈异常拟合方法研究

传统的BP神经网络在GPS高程异常拟合应用有其一定的局限性,特别是在对于外推高程异常值方面,传统的BP神经网络的不足表现得尤为明显.针对高程异常的特性,既有趋势性也有随机性,结合BP神经网络的优点,提出一种改进型的BP神经网络高程异常拟合方法,利用最小二乘配置法综合考虑高程异常的趋势性和随机性的特点,采用BP神经网络方...     

益阳市似大地水准面精化成果分析

利用重力场模型、数字高程模型、水准测量成果和GPS技术,采用重力法与移去恢复技术,分析和研究了益阳城区似大地水准面精化获取的技术和方法,并对获取的似大地水准面进行了精度评定。     

高程异常模型的RTK/水准抗差技术

采用RTK/水准确定两套坐标转换模型时,RTK测量的精度限制会降低模型精度.本文经推导论证,通过高程异常模型定位粗差,隔离粗差后可有效提高转换精度.最后通过工程算例验证了该方法的实用性.该技术可应用于不同坐标系坐标转换工作.     

假3°带坐标系及关于大城市坐标系的建议

现时许多地方和工程坐标系在坐标数值和方位上与国家标准3°带里的偏差很大,使得其地形图无法与国家标准3°带的对接,并导致工程实践中许多的麻烦和不便;许多地方坐标系有效带宽太小。本文通过一个简单的公式,一次完成控制网的换带、旋转、放大、平移,获得控制网的"假3°带坐标系"坐标。假3°带坐标系具有诸多优点:坐标数值和方位与国家标准3°带的偏差极小,地形图可与国家的对接;有效带宽极大;便于CORS系统流动站使用;做法简单,适用广泛,可用于全国绝大部分地方坐标系。文章还对大城市坐标系的建立提出了有益建议。     

Comparative assessment of the relationship of satellite data with the above ground biomass of Sal trees (<Emphasis Type="Italic">Shorea robusta</Emphasis>) determined from phenologically different time periods

The Above Ground Biomass(AGB) estimates of vegetation comprise both the bole biomass determined through a volumetric equation and litter biomass collected from the ground.For mature trees,the AGB estimated in phenologically different time periods is directly affected by the litter biomass since the Diameter at Breast Height(DBH) and height(H) of such trees that are used in the estimation of bole biomass would remain unchanged over a reasonable time period.In the present study,we have determined the AGB of Sal trees(Shorea robusta) in two contrasting seasons:the peak green period in October being devoid of lit-ter on the ground and the leaf shedding period in February with abundant amount of litter present on the ground.Estimation of AGB for the month of February included the litter biomass.In contrast,the AGB for October represented only the bole biomass.AGB was estimated for ten different plots selected in the study area.The AGB estimated from ten sampling plots for each time period was re-gressed with the individual tree parameters such as the average DBH and height of trees measured from the corresponding plots.The regression analysis exhibited a significantly stronger relationship between the AGB and DBH for the month of October as compared to February.Furthermore,the correlation between the remotely sensed derived data and AGB was also found to be significantly higher for the month of October than February.This observation indicates that inclusion of the litter biomass in AGB will tend to decrease the re-gression relationship between AGB and DBH and also between the remotely sensed data and AGB.Therefore,these conclusions invite careful consideration while estimating AGB from satellite data in phenologically different time periods.     

吉林长白山森林冠顶高度激光雷达与MERSI联合反演

将激光雷达与光学遥感相结合进行区域林分冠顶高度联合反演,提出了大脚印激光雷达GLAS脚点波形数据处理和不同地形条件下的森林冠顶高度反演算法,并建立了区域尺度不同森林类型林分冠顶高度GLAS＋MERSI联合反演模型,制作了长白山地区森林冠顶高度图。     

移动曲面拟合用于高程控制测量的探讨

多项式曲线拟合、三次样条曲线拟合、多项式曲面拟合、多面函数曲面拟合、移动法曲面拟合是全球定位测量水准拟合常用方法,本文结合实例,分析多种方法获得数据的精度,并通过工程实例比较和分析,认为移动法曲面拟合拟合法精度更高且稳定,具有较高的可靠性和实用价值。     

DMC数码航摄区域网布点方案探讨

相片控制测量是航空摄影测量的基础工作,传统航空摄影控制测量有成熟的作业方法和相应的技术标准和规范,而DMC航空摄影控制测量还没有制定相应的技术标准或规范,特别是在中小比例成图的应用中,更是一个空白。根据DMC航空摄影资料的特点和1：10 000地形图成图的精度要求,通过实例研究,总结区域网布点方案的规律性。     

北半球500 hPa位势高度场时空频谱特征分析

利用1979～2004年NCEP2再分析资料,对逐日的北半球(20°N～90°N) 500 hPa的位势高度进行二维傅里叶的谱展开,并分析了不同波数下的谱展开系数的频域特征.对全年序列分析的结果表明:当纬向波数k和经向波数l均为0时,其谱展开系数表现为显著的低频(10～30天)变化特征;当经向波数l=0时,其谱展开系数...