Geog103_Ch1
GEO卫星测距系统设计
GEO卫星测距系统设计
朱振华;冯阳凯;郭润全
【期刊名称】《信息技术》
【年(卷),期】2010(000)012
【摘要】随着卫星测定轨精度的提高,现有测距系统难以满足要求.文中着重介绍了GEO卫星采用三点测距为实现高测距精度的方案,给出了三点测距系统的结构和功能,并分析测距系统模型,以及提高测定轨精度的因素,最后对测距性能进行了分析.【总页数】5页(P94-98)
【作者】朱振华;冯阳凯;郭润全
【作者单位】上海交通大学,上海,200000;上海卫星工程研究所,上海,200240;上海卫星工程研究所,上海,200240
【正文语种】中文
【中图分类】TH761.2
【相关文献】
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2.基于GEO卫星分段测距资料的定轨研究 [J], 乔荣川;李志刚;奚小瑾;冯初刚;杨旭海
3.分米级USB测距在GEO卫星定轨中的应用 [J], 陈建荣; 李俊峰; 李少敏; 刘蓉
4.嵌入式高精度激光测距系统设计 [J], 胡宁波;王晗;张平;张家峰;胡钊雄
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一种适合高山发射台卫星接收天线的智能融雪除冰系统的设计与应用
一种适合高山发射台卫星接收天线的智能融雪除冰系统的设计与应用摘要：本文针对高山发射台潮湿寒冷的气候特点，设计出一套可根据天气状况自动对卫星接收天线进行融雪除冰的系统，系统采用数据采集控制器，基于TCP/IP通信协议，利用台内传输网，通过配置温度、湿度、雨雪传感器及高清视频摄头，PLC自动化控制系统及相关控制软件，实现PC值班终端与掌上智能控制终端相结合，实现对卫星接收天线的数字化、网络化、智能化管理。
关键词：卫星天线自动化融雪除冰1.前言某发射台地处海拔1800米的高山上，由于海拔较高，潮湿度很高，下雪、冻雨、冰凌等恶劣天气发生频率较高，恶劣天气下卫星天线的主反射面上容易形成一层厚厚的积雪或冰冻体，对天线主反射面的曲面物理特性造成破坏，从而导致卫星天线口面分布函数的均匀性失衡、天线增益降低及噪声温度升高、天线的信号传输质量劣化等，影响到卫星信号的接收，严重时会造成信号中断。
早期台站为排除这一影响，采用的办法是人工值守、人工扫雪除冰的方式，但是人工扫雪除冰的效率低，操作难度大，同时发射台卫星天线安装的位置非常险峻，这又增加了作业人员的操作难度，也容易造成人身安全事故。
为了解决这一难题，我们学习了各地卫星接收系统的运维方式，结合高山台站的气候及地理特征，设计出这套智能型、高效率的卫星天线融雪除冰系统。
2.技术方案卫星接收天线智能融雪除冰系统由专用电热膜加热系统、雨雪传感器、温度传感器等传感系统、 PLC逻辑控制系统、网络传输及远程终端控制系统几大部分组成，系统构成如图1所示。
图1、系统构成简图2.1电热膜加热系统采用具有高分子聚合物的特性发热材料，其材料中的金属粒子和自由电子受到激发，电子碰撞和摩擦导致布朗运动，撞击的摩擦产生热能，热量主要以远红外低温辐射的形式传输，热效率高，发热量非常均匀。
卫星天线由12个分瓣组成，我们将加电热膜附着在卫星天线背面。
每3瓣成一组，分成3组，间隔安装，循环供电。
这样设置是为了降低运行总功率，均衡发热，在其中一组，甚至两组发生故障后还能实现融雪除冰的功能。
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Two Terms:
and due to the tilt of its axis The Planet Earth
The Earth rotates on
revolves around the
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©Boken-UNK-Geography 103
spatial changes too that
occur on the Earth’s surface
variation/change Spatial
and Florida during the winter time.
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this course?
However..
The focus is on
What is a disaster?
What is a natural disaster?
A sudden change causing significant
Question?
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A good source of information
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[NOAA photo library]
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[www.NOAA .gov]
Very useful source of information
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contd…
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In all of the disasters Human fatalities in natural disasters
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Human response to a disaster
across 377 counties] revealed
Increase in suicides
disaster disaster
Frequency of a disaster Frequency and probability
More on probability…magnitude and frequency Return Period Contd…
More explanation…
The relationship between the magnitude
and the frequency of a disaster
Magnitude Higher magnitude
Average magnitude Lower magnitude
©Boken-UNK-Geography 103What happens to the probabilities when the magnitude increases from 10-fatalities (lower magnitude) to 1000-fatalities (higher magnitude)?
What happens to the probabilities as the length of period increases from 1 to
to 10 to 20 years?
Do they increase or decrease?
©Boken-UNK-Geography 103
Real Data
Two characteristics of population:
the occurrence of natural disasters?
Population growth rate
An example
Suppose the population living at a place is Spatial variation in the population growth rate
[CIA factbook]
Which continent has the highest (or lowest) population growth rate? Answer.
©Boken-UNK-Geography 103
World Population
©Boken-UNK-Geography 103
Why is the population curve not a straight line?
exponential (not linear)
Formulas for linear and exponential equations?
What is Doubling Time?
Table 1.7
©Boken-UNK-Geography 103
If the growth rate increases, doubling time…....... (?)How to compute Doubling Time?
Q. Apply a compound interest formula and compute Doubling Time for a
population that is growing at an annual growth rate of 1%.
©Boken-UNK-Geography 103
T
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Pay attention to continents with highest and lowest ‘yearly growth’ i.e. growth rate
Population Density
(the number of people per sq. km)
©Boken-UNK-Geography 103
Again, pay attention to countries/continents with highest/lowest population density.
Hongkong and Mongolia:
Contrast in the population density
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©Boken-UNK-Geography 103
An increasing population means more and more people having to live on the natural-disaster-prone zone
Population and natural disasters
Answer the following few questions (1.
Define these terms: natural disaster, return
period, doubling time of population, exponential growth, population growth rate, altruism, population density.
2.
Which continent has the highest population growth rate? which has the lowest?
3.
Can the human population continue to grow for ever?
What did you learn in Chapter 1?
©Boken-UNK-Geography 103
contd…。