基于STK的预警飞机场景仿真研究

为了使预警飞机能够根据既定目标有效地搜索、监视和跟踪,研究了一种基于卫星工具包(STK)的传感器,对预警飞机的作战方案进行了仿真、验证和演示,使预警飞机能够满足未来军事规划阶段需求,从而进一步提高预警飞机的军事作用。     

高分辨率波长位移解调技术研究进展

简要阐述了在光纤传感技术中实现高分辨率波长位移解调技术的基本原理,重点介绍了几种典型解调方法的结构和原理以及波分复用的方案,最后对各种解调方案的优缺点进行了比较分析.     

UHF频段陆地卫星移动通信业务多径效应测量

UHF测段陆地卫星移动业务多径实验于1999年6月至8月间利用日本GMS140E气象卫星为信标,分别在河南郑州至开封高速公路、林州至上党方向公路以及石家庄至阳泉高速公路段进行。地面接收系统和数据处理设备安置于汽车上。此项实验的目的是为地面卫星移动通信系统的设计提供重要的信道参数。本文给出了不同环境下多径效应的累计分布特性以及相应的预测模型。     

强度调制型光纤接近觉传感结构及发展新趋势

对近年发展的几种有代表性的强度调制机器人光纤接近觉传感的结构、机理进行了系统的介绍和比较,指出了传感结构设计需要考虑的关键问题以及今后发展趋势。     

遥感技术的应用及发展

高科技、环境资源、信息工程、可持续发展与经营意识和市场经济正成为当今世界现代化高度融合、密不可分的决定性力量。遥感技术作为集成了众多高科技的现代科学,在各个领域应用的深度和广度,正在飞速扩展着。本文就其在若干方面的最新进展作一综述。     

卫星ATM网络资源共享方式的研究

本文针对ＡＴＭ技术在卫星网络中的应用，就如何实现卫星频率资源的分配，以提高全网统计复用的增益，降低信元的丢失率，提出了一种新的排队模型：二级队列共享。并根据卫星信道的特点，采用混合多址方式ＴＤＭＡ／ＣＤＭＡ，实现二级队列资源共享。最后对话音信源模型（ＯＮ／ＯＦＦ模型）在该共享方式下的性能作了计算机模拟，并给出了有关结论。     

AN ATM-LIKE SYSTEM ARCHITECTURE FOR SATELLITE COMMUNICATIONS INCLUDING ON-BOARD SWITCHING

In this paper, an ATM system architecture for satellite communications is described. The proposed architecture includes an on-board switch and implements the adaptation of real-time services (e.g. voice and video) and non-real-time services (e.g. data) to the satellite communication link, while achieving statistical advantage. To this end, the ATM traffic categories defined in recent specifications^1,2 are utilized. Real-time and non-real-time traffic components are simultaneously supported by a TDMA/TDM on the satellite uplink/downlink, respectively. By exploiting the burstiness of real-time traffic, the proposed satellite system architecture achieves a significant increase of the overall system throughput. After describing the satellite system architecture and addressing scheme, we derive analytical models, by using sophisticated queueing models that allow a very accurate performance evaluation and an easy dimensioning of the data buffers. The proposed model is validated with simulations. The main result is the assessed feasibility of on-board buffers with current technology, even under very strict performance requirements on cell loss ratio and for quite high load values (e.g. 80 per cent of the downlink capacity). Finally, a congestion control scheme, based on a combination of preventive and reactive strategies, is proposed and analysed.     

Application of remote sensing in studies of water quality in the Amazon Region

This paper deals with some basic matters concerning the use of remote sensing techniques related to limnological/water quality surveys in the Amazon Region. The main conclusions are: (i) it is important to use these techniques for detecting problems before the construction of new projects involving water resources in the Amazon Region; and (ii) remote sensing focused on water quality should be seriously considered in planning Brazil's space program as a means of providing data for more effective water basin management.     

天线系统数字引导精度分析

数字引导是一种重要的天线工作方式，广泛应用在卫星测控、遥测和遥感地面站天线系统中。本文论述及分析了天线系统数字引导的方法和引导精度。     

基于小波包分解的遥感图像压缩方法

基于小波包分解的遥感图像混合编码方法,首先将小波包分解后的低频和高频小波系数域值化为重要系数和非重要系数.低频重要系数采用无失真编码压缩.高频重要系数及其位置图,先用数学形态学方法进行聚类,再用标量量化和行程编码对重要系数和位置图分别编码.试验证明这种方法有效.