第七章我们讨论了数字调制的三种基本方式:数字振幅调制、数字频率调制 和数字相位调制,然而,这三种数字调制方式都存在不足之处,如频谱利用率低、 抗多径抗衰落能力差、功率谱衰减慢带外辐射严重等。 为了改善这些不足,近几十年来人们不断地提出一些新的数字调制解调技 术,以适应各种通信系统的要求。例如,在恒参信道中,正交振幅调制(QAM) 和正交频分复用(OFDM)方式具有高的频谱利用率,正交振幅调制在卫星通信和 有线电视网络高速数据传输等领域得到广泛应用

坐标系统和时间系统是描述卫星运动、处 理观测数据和表达观测站位置的数学与物 理基础

4.1条码技术 4.2条码技术的应用 4.3物流标识技术的应用 4.4电子数据交换(EDI)技术的应用 4.5射频技术的应用 4.6地理信息系统(GIS)技术的应用 4.7全球卫星定位系统(GPS)技术的应用

1.1大地测量学的定义、分类和任务 定义:大地测量学是为人类活动提供空间信息的科 学,着重研究地球的几何特征(形状和大小)和 基本物理特性(重力场)及其变化。 分类:几何大地测量、物理大地测量 几何大地测量:经典大地测量、空间大地测量 物理大地测量:地面重力、航空重力、卫星重力

Outline Purpose of thermal control systems Review of heat transfer fundamentals Space system thermal analysis equations Models Analysis programs Thermal control sub-systems

Background An icbm with a range of 6500 miles has a stagnation temperature of 12,000%F, 2000 f hotter than the surface of the sun Calculations showed that the optimum design for structural strength, resistance to heating, and free flight stability was a long, needle nosed reentry body But it would vaporize during reentry

The telemetry, tracking and control subsystem provides vital communication to and from the spacecraft TT&c is the only way to observe and to control the spacecraft's functions and condition from the ground October 29 2003 Massachusetts Institute of Technology

Autonomy Technologies Fault Detection, Isolation and Recovery Planning & Scheduling Intelligent Data Understanding Path Planning Gradient method

Why Cost Estimation? Critically important part of system design Too high- lose the contract award Too low-over-run cost plus contracts, company loss on fixed price contracts Trends Design to cost Cost as an independent variable

Deployment and Geometry Maintenance Deployable Membranes Used for solar arrays, sunshields, decoys Being researched for apertures starting at RF and eventually going to optical Inflatables First US satellite was inflated (ECHO D) Enables a very large deployment ratio -=deployed over stowed dimension