基于FastSLAM的绳系机器人同时定位与地图构建算法

绳系式移动机器人可用于极端地形的探测,如陡峭斜坡、松软土壤、高耸悬崖、沟壑等。在运动过程中移动机器人的绳索不可避免地与障碍物接触甚至缠绕。由于绳索与障碍物之间的接触点不相互独立以及机器人模型的非线性特性,经典的FastSLAM框架不适用于绳索机器人的同时定位和地图创建（SLAM）问题。提出基于改进FastSLAM框架的绳系机器人SLAM算法。在该框架中,分别利用无迹滤波和粒子滤波解决接触点位置估计和机器人位姿估计问题,并利用非线性观测模型的无迹变换来简化粒子权重更新。仿真结果表明,该算法可有效地估计接触点位置,同时提高机器人位姿估计性能。     

Morphometric,rheological and compositional analysis of an effusive lunar dome using high resolution remote sensing data sets: A case study from Marius hills region

Domes, an analog of the terrestrial shield volcanoes are one of the important volcanic features found on the lunar surface. Such volcanic features are windows to better understanding of the contrasting natures of lunar volcanism, giving an insight into the source and the nature of the basaltic magmas. Marius Hills Complex is one of the most important regions in the entire lunar surface for having a complex setting of volcanic constructs with an abundant number of volcanic features like domes, cones and rilles. As a part of initiation of the study of Marius Hills volcanism, an effusive dome located to the south of Rima Galilaei, near the contact of Imbrian and Eratosthenian geological units is taken for the present study. Inferring from the Terrain Mapping Camera-Digital Elevation Model (TMC-DEM), the morphometric parameters are estimated (350 m in height, 9.62 km in diameter), and accordingly the rheological parameters are also estimated. As the signatures of multiphase eruption are not clear geomorphologically and also in topography, the dome is assumed to evolved in monogenetic eruption. The causative dike parameters of the dome are estimated, which gives upper bounds of true values of the parameters. The estimated feeder dike length (150 km) and width (233 m) implies that the source region is lying most probably in the mantle portion of moon. The crater size frequency distribution (CSFD) is applied to determine the age of the particular dome and also the surrounding mare surface so as to better construct a stratigraphic correlation. It is found that dome belongs to oldest age unit of Marius Hills region while the surrounding units are relatively younger. Using Chandrayaan-I Moon Mineralogy Mapper (M³) data, the surface composition for the study area is also analysed. Thus, the morphometry, rheology, dike parameters, age determination and mineralogy are found to be in good agreement with results of the earlier studies. Such a study, covering all the domes and other volcanic features in Marius Hills using high resolution data sets will provide a clear and better understanding of the volcanic history of the region and the Oceanus Procellarum Basin as well. In such a study, the application potential of high resolution Chandrayaan-I TMC image and its DEM generated from the stereo data has been useful.     

基于联合映射的高速数传发射机设计及其查找表法实现

根据高速数传发射机的要求,提出基于联合映射的高速卫星发射机设计及基于查找表的FPGA(F ieldProgramm ab le Gate Array,现场可编程门阵列)硬件实现方案。该方法将发射机中数字部分的TCM编码和成形滤波一起设计,将多个卷积相乘项相加后再量化,减少了量化次数,提高了量化信噪比。并根据FPGA芯片内部结构设计硬件实现方案,符合SOC(System of Ch ip)的趋势。用片内的BLOCKRAM精心设计查找表,在X ILINX公司25万门芯片VIRTEX2-250中就能实现此方案。MODELSIM的时序仿真结果表明可支持高达200Mb it/s的数据。文章结尾针对未来更高速率的高速数传发射机给出了一种通用硬件实现方法。     

基于庞加莱映射的多站数据融合算法

针对目前单目标跟踪数据融合中存在的伪数据问题,研究了基于庞加莱映射的补充条件定位引导算法和多站抗野值数据融合算法,建立了适应实际传感器数量变化的数据融合体系。理论分析和仿真结果均证明,该方法可行有效。     

Comparison of ANN and MLR models for estimating solar radiation in Turkey using NOAA/AVHRR data

In this paper, the estimation capacities of MLR and ANN are investigated to estimate monthly-average daily SR over Turkey. The satellite data are used for 73 different locations over Turkey. Land surface temperature, altitude, latitude, longitude and month are offered as the input variables for modeling ANN and MLR to get SR. Estimations of SR are evaluated with the meteorological values by using the statistical bases. The obtained results indicated that the ANN model could achieve a satisfactory performance when compared to the MLR model. Moreover, it is understood that more accurate results in estimation of SR are obtained in the use of satellite data, rather than the use of meteorological station data. Finally, the built ANN model is used to estimate the yearly average of daily SR over Turkey. As a result, satellite-based SR map for Turkey is generated.     

月球遥感立体测绘技术的发展

对国外月球探测测绘历程进行了调研总结,并针对立体观测、干涉雷达测量、扫描激光测绘等3种主要的测绘方案进行分析比较,继而提出适合中国月球探测目标的三维遥感测绘成像技术途径。     

传输型测绘相机内方位元素误差对高程精度的影响分析

文章通过对摄影测量学中基于空间前方交会的点投影系数法进行分析,建立了摄影测量的高程误差方程,重点分析了传输型测绘相机内方位元素误差对高程精度的影响。以1∶50 000比例尺地图产品为例,分析了某测绘相机的相机主距、主点位置、畸变等内方位元素对高程精度的影响程度,提出在测绘相机研制过程中在保证高程精度方面应注意的问题。     

基于冗余连接机制的SLE网络协议体系模型

CCSDS(Consultative Committee for Space Data Systems,空间数据系统咨询委员会)SLE(Space Link Extension,空间链路拓展)网络协议体系模型中,一个服务实例只支持建立一个物理通信链路,造成上层应用与下层链路耦合过强,存在一定的安全隐患。针对此问题,设计了基于冗余连接机制的SLE网络协议体系模型,该模型在现有的SLE网络协议体系模型中增加了逻辑连接层,支持单一服务实例同时使用多个物理链路进行空间数据传输,可根据多连接状态重新设计TML(Transport Mapping Layer,传输映射层)状态变换关系以及数据传输模式。该模型能够兼容现有的SLE网络传输体系模型,提高SLE服务的可靠性。     

深空干涉测量对流层经典模型改进

对流层延迟修正误差是深空干涉测量的重要误差源之一。通过修正对流层经典天顶延迟模型和Niell映射函数NMF（Niell Mapping Function）构建了一种高精度区域对流层延迟模型。首先，结合我国深空网喀什深空站对流层延迟实测数据，对Saastamoinen模型的适用性进行分析，通过线性最小二乘拟合修正天顶干延迟参数，模型精度相对改善29.6%；然后，针对NMF低仰角情况下映射偏差较大的问题，构建偏差函数模型，显著改善了低仰角下的映射性能，经实测数据验证：仰角在0°~30°时，对流层延迟模型偏差相对改善约30%。改进后的对流层区域模型估计精度高，可为我国深空干涉测量对流层延迟修正提供参考。