数字地图系统及其应用

本文介绍数字地图在航空电子方面的应用。数字地图存贮数字化航图、地形高程数据、地形特征分析数据,任务数据、导航数据、威胁情报等数据。在机载环境下实时检索重建存储的地图信息,产生响应飞机飞行运行的彩色活动数字地图,为驾驶员导航及环境评估提供信息。数字地图与先进的航空电子系统相结合,可以实现地形参考导航、地形跟随、地形回避、威胁回避等功能,大大地提高任务的有效性及自身的生存力。数字地图在航空电子的应用方面具有非常广阔的前景。     

《航空电子技术》2001年总目录

系统与综合 期号 页次 1553B总线监视器系统软件设计3 ( 1 ) 应用于未来航电系统的互连标准——SCI/RT4 ( 1 ) SAE线性令牌传输总线与光纤型分布式数据接口规约的比较4 ( 6 ) 对新一代综合航电系统发展的探讨4 (11) 传感器综合技术刍议4 (19) 网络、信息交联与传输 民机数据总线信号综合测试仪1 ( 1 ) 基于RS-232总线的故障1 ( 5 ) SCI协议标准综述2 ( 9 ) 特种飞机航空电子设备支援系统研究2 (19) 多传感器数据融合中的数据配准研究2 (24) 一种高效的数字地图高程数据存储格式3 ( 6 ) 数据融合体系结构的设计4 (25) 计算机、软件及算…     

一种数字地图生成软件介绍

KineMap~(TM)数字地图软件是一个强大的工具集,可用于生成适用于陆海空三军的高级战术移动地图。该产品的可升级、开放式系统的体系结构令地图开发者能够综合多种格式和级别的数据以及任务信息。其应用程序接口保证了它与现有的航空电子或导航显示的移动地图相综合的能力。KineMap~(TM)数字地图软件是用C++实现的面     

可配置片上数据存储的统一存取

针对DSP应用领域高实时性和大容量存储的需求，提出了一种基于MCU-DSP融合架构处理器的可配置片上数据存储统一存取设计方法。介绍了片上数据存储的总体结构与其内部数据存储的组织结构，采用非连续字节编址模式和特殊的访存地址分割与组合，结合类零级 Cache 的数据行缓存，实现了片上数据存储 Cache 和SPRAM（Scratch-pad RAM）的可配置与高速统一存取。     

一种块级连续数据保护的系统设计

提出了一种基于逻辑卷的连续数据保护系统的设计方案，论述了它的系统结构以及实现方法。。该系统不依赖于具体的存储设备，能实现数据块级的连续保护，并可以实现保护时间区间内任意时间点的恢复。系统提供了独特的数据存储组织结构和相应的空间管理策略，并且具有很好的恢复技术，该系统提供了一种经济、通用的纯软件方案，能广泛推广应用。     

SQL SERVER实现数据访问和事务处理的一种方法

本文介绍了ＳＱＬＳｅｒｖｅｒ实现数据访问和事务处理的一种重要方法─存储过程；重点阐述了存储过程的构成、优点、创建、执行及其在实际开发中的应用。     

低空突防实时仿真中DED数字地图的地形提取技术研究

DED地形文件格式是MutiGen公司的专有数据格式,尚无关于其数据存储格式的详细说明,为在低空突防实时仿真系统中应用DED地形数据构建地形探测雷达模型、验证突防算法,通过实验分析得出DED地形文件信息存储格式,给出了地形数据提取与坐标转换的算法,有效地克服了低空突防实时仿真中缺乏大范围高精度地形数据的问题,解决了数学仿真和视景仿真地景完全匹配的难点问题。     

数字地图和GPS构成的无源地形跟随系统

能提供足够精度的飞机位置，速度和航向的全球定位系统与提供航线周围的地形数据的数字地图系统结合，能产生地形跟随飞行所需的ＴＦ控制指令，数字地图和ＧＰＳ构成地形跟随系统是一个无源系统。它从根本上消除了由于发射电磁波而暴露的可能性。     

一种智能的惯导陀螺漂移误差消除算法

给出了一套智能的消除惯导陀螺漂移误差算法,即改进的BP(Back Propagation)神经网络模态识别算法。可根据即时的飞行区域、气压计和雷达高度表测量的地形高程数据等,在机载数字地图上实时地进行在线模态识别,找出最合适的匹配区,并对惯性导航系统指示的位置信息进行修正。该算法具有识别精度高、识别速度快和识别准确率高等特点,可用于各类有人驾驶飞行器和无人自主控制的飞行器的惯导误差修正。     

CAPP与PDM数据交换技术

探讨了在PDM集成框架下CAPP从PDM数据库中获取产品属性信息、产品结构信息和产品图形信息的方法;研究了CAD/CAPP/PDM系统中数据文档的格式和类型,并将不同格式的文档划分为无格式文档和有格式文档;详细阐述了CAPP生成的工艺文档、工艺要素及属性信息在PDM框架下进行CAPP数据存储的一个模型和应用实例.     

The ERIM interferometric SAR: IFSARE

The Environmental Research Institute of Michigan (ERIM) and Horizons, Inc. have completed the development, calibration and evaluation of the Advanced Research Projects Agency (ARPA)/US Army Topographic Engineering Center (TEC) funded IFSARE (Interferometric Synthetic Aperture Radar for Digital Terrain Elevations) system. This system rapidly produces geocoded SAR imagery and digital terrain elevation data. The dual-channel, X-band SAR is installed in the ERIM Learjet 36. The ground processor was developed in collaboration with the NASA Jet Propulsion Laboratory. The system produces 1.5 to 3.0 meters (1 sigma) absolute accuracy three-dimensional terrain elevation data over large areas without the use of ground control points. Several examples from recent data collections are presented     

Implementing digital terrain data in knowledge-aided space-time adaptive processing

Many practical problems arise when implementing digital terrain data in airborne knowledge-aided (KA) space-time adaptive processing (STAP). This paper addresses these issues and presents solutions with numerical implementations. In particular, using digital land classification data and digital elevation data, techniques are developed for registering these data with radar return signals, correcting for Doppler and spatial misalignments, adjusting for antenna gain, characterizing clutter patches for secondary data selection, and ensuring independent secondary data samples. These techniques are applied to select secondary data for a single-bin post-Doppler STAP algorithm using multi-channel airborne radar measurement (MCARM) program data. Results with the KA approach are compared with those obtained using the standard sliding window method for choosing secondary data. These results illustrate the benefits of using terrain information, a priori data about the radar, and the importance of statistical independence when selecting secondary data for improving STAP performance     

The development of a digital video motion detection test set

This paper describes the current effort to develop a standardized data set, or suite of digital video sequences, that can be used for test and evaluation of digital video motion detectors (VMDs) for exterior applications. We have drawn from an extensive video database of typical application scenarios to assemble a comprehensive data set. These data, some existing for many years on analog videotape, have been converted to a reproducible digital format and edited to generate test sequences several minutes long for many scenarios. Sequences include non-alarm video, intrusions and nuisance alarm sources, taken with a variety of imaging sensors including monochrome CCD cameras and infrared (thermal) imaging cameras, under a variety of daytime and nighttime conditions. The paper presents an analysis of the variables and estimates the complexity of a thorough data set. Some of this video data test has been digitized for CD-ROM storage and playback. We are considering developing a DVD disk for possible use in screening and testing VMDs prior to government testing and deployment. In addition, this digital video data may be used by VMD developers for further refinement or customization of their product to meet specific requirements. These application scenarios may also be used to define the testing parameters for future procurement qualification. A personal computer may be used to play back either the CD-ROM or the DVD video data. A consumer electronics-style DVD player may be used to replay the DVD disk. This paper also discusses various aspects of digital video storage including formats, resolution, CD-ROM and DVD storage capacity, formats, editing and playback     

Terrain intervisibility-believe it or not?

Computer generated digital maps with terrain intervisibility displays are becoming a common addition to aircraft cockpits. Also known as masking plots, these displays show dangerous regions exposed to threats, highlight terrain visible from the current (or future) aircraft location, and keep track of regions hidden from view during searches with various types of sensors. High resolution displays of semi-transparent intervisibility overlaid on sharp clear digital maps are very convincing but can they be believed? Not completely. Intervisibility displays serve a valuable function. But to build and use these systems wisely, it is good to understand the errors and limitations involved. At LMFS, we have integrated digital maps from other companies into avionics systems such as Army Special Operations Aircraft and MH-53J, and have analyzed the errors associated with the use of level 1 and level 2 terrain elevation data from the National Imagery and Mapping Agency (NIMA). We have also developed a number of real-time intervisibility and probabilistic intervisibility functions using a hybrid of multiresolution techniques and algorithms to obtain the best results possible for a given set of computer resources. This paper explores some of the problems, solutions, and human/machine interface considerations associated with the generation and use of intervisibility     

单光子激光雷达数据去噪与滤波算法

单光子激光雷达获取的点云数据存在大量噪声,这给数据的处理带来了挑战。基于局部距离统计提出了改进的点云去噪算法,对单光子激光雷达点云原始数据进行去噪。然后基于统计分析方法改进了点云滤波算法,对去噪后的点云数据进行滤波处理。利用新提出的算法与传统算法去噪和滤波后得到的点云进行比较,并与传统激光雷达的数字地形模型(DTM)数据进行对比。计算得到MABEL地面点云相对于传统激光雷达高程的均方根误差RMSE为2.98m,相关系数R^2为0.9938。进一步对地面点云插值得到剖面数字高程模型(DEM)数据,其相对于传统激光雷达高程的均方根误差RMSE为2.85m,相关系数R^2为0.9931。实验结果显示,提出的单光子激光雷达点云去噪和滤波算法优于传统算法,与传统激光雷达DTM数据具有较好的相关性,能够精确的恢复地形信息。     

An overview of a Global Positioning System Mission Plannerimplemented on a personal computer

The Global Positioning System (GPS) Mission Planner (GMP) program, which has been implemented on an IBM PC, is described in terms of its features and architecture, and sample outputs are presented. The GMP was written to permit operational units to plan missions and to accomplish survivability and navigation assessments based on realistic trajectories, GPS almanac data, broadband jammer specifications, and digital terrain elevation data (DTED). GMP supports trajectory generation for generic air, land, or naval vehicles and has `sanity' checks for altitude acceleration, terrain slope, and velocity limits. A survivability measure is computed based on exposure time to various threat types. Yuma-type almanac data are used to support the GMP to define GPS satellite orbits. Jammers, threats, and trajectory wavepoints may be defined by either keyboard entry (e.g. longitude, latitude, and altitude) or via mouse and cursor on a displayed pseudo-color DTED map on the PC monitor. Satellite visibility and best dilution-of-precision (DOP) are computed using DTED. jammer visibility and power levels at the vehicle are similarly computed. A realistic body masking and antenna gain model is used to compute carrier-to-noise densities for each visible satellite. A navigation assessment program emulates a multichannel receiver to generate position and velocity measurement uncertainties. An integrated Kalman filter generates position and velocity navigation estimates. Results are graphically displayed to the operator     

ArcGIS中基于 DEM提取沟道特征

以陕西省延安市大南沟小流域5 m分辨率DEM数据为基础,利用ArcGIS9.3的grid模块平台提取研究区的沟道特征。在对原始地形数据进行填洼预处理后,生成河道沟系走向栅格数据、流域汇水面积栅格数据;然后,设定合适的临界汇水面积值提取出河道沟系;最后,对河道沟系进行分级。结果显示,提取出的沟道系统与实际基本吻合。     

三维数字地形图生成技术研究

在论述三维真实感数字地形图生成算法的基础上,结合数字高程模型(DTM)数据,用OpenGL在计算机上实现三维数字地形图的显示。     

复杂航迹和起伏地形条件下机载聚束SAR 空变运动补偿

 运动补偿是雷达平台机动飞行条件下合成孔径雷达(SAR)实现精确聚焦成像的前提,而如何精确实现运动误差的空变补偿(误差补偿随目标距离、方位和高度位置的变化而变化)目前还存在很大的挑战。本文提出了一种新的三阶运动补偿方法,能够有效解决复杂雷达航迹和地形起伏条件下运动误差的空变补偿问题。该方法首先以场景中心为参考进行空不变运动补偿,然后以多个子场景中心为参考进行空变运动补偿,最后再利用极坐标格式算法(PFA)统一补偿每个像素的空变误差。仿真数据处理结果验证了本文方法的有效性。