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document.write('<font color=\"\">动中通<\/font>');
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document.write('          <div style=\"color:#999999;text-align:center\"><strong>更新时间：<\/strong>2012.11.20 <strong>浏览次数：<\/strong>174<script language=\"javascript\" src=\"HitCount.Asp?action=count&LX=LiangjingCMS_Others&id=31\"><\/script><\/div>');
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document.write('            <p><b><span style=\"font-size: 10.5pt; \">一、<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&ldquo;<\/span><span style=\"font-size: 10.5pt; \">动中通<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&rdquo;<\/span><span style=\"font-size: 10.5pt; \">系统构成<\/span><\/b><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&nbsp;<br \/>');
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document.write('            &ldquo;<\/span><span style=\"font-size: 10.5pt; \">动中通<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&rdquo;<\/span><span style=\"font-size: 10.5pt; \">是由卫星自动跟踪系统和卫星通信系统两部分组成。<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&nbsp;<br \/>');
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document.write('            1<\/span><span style=\"font-size: 10.5pt; \">、卫星自动跟踪系统<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&nbsp;<br \/>');
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document.write('            <\/span><span style=\"font-size: 10.5pt; \">卫星自动跟踪系统是用以保证卫星发射天线在车体运动时对卫星的准确指向。其主要设备有：<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&nbsp;<br \/>');
document.write('            (1)<\/span><span style=\"font-size: 10.5pt; \">天线座，采用卸载和储力方式减小天线传动时的负载惯量。<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&nbsp;<br \/>');
document.write('            (2)<\/span><span style=\"font-size: 10.5pt; \">伺服，采用位置环或速度环控制方式，使用模拟硬件提高电路响应速度，减小伺服<\/span><span style=\"font-size: 10.5pt; font-family: Arial; \">&nbsp;<\/span><span style=\"font-size: 10.5pt; \">跟踪系统的动态滞后误差。<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&nbsp;<br \/>');
document.write('            (3)<\/span><span style=\"font-size: 10.5pt; \">数据处理，使用专用的数学解算平台，对误差信号、载体的动态信号进行处理，解算出天线的控制信号。<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&nbsp;<br \/>');
document.write('            (4)<\/span><span style=\"font-size: 10.5pt; \">载体测量，使用捷联惯导测量组合测量出载体的变化量，使其反应在天线跟踪上。其中，激光陀螺是在光学干涉原理基础上发展起来的新型导航仪器，成为新一代捷联式惯性导航系统理想的主要部件，用于对所设想的物体精确定位。石英挠性摆式加速度计是由熔融石英制成的敏感元件，挠性摆式结构装有一个反馈放大器和一个温度传感器，用于测量沿载体一个轴的线加速度。光纤陀螺三轴惯测组合由三个光纤陀螺仪和三个石英挠性摆式加速度计组成，可以实时地输出载体的角速度、线加速度、线速度等数据，具有对准、导航和航向姿态参考基准等多种工作方式，用于移动载体的组合导航和定位，同时为随动天线的机械操控装置提供准确的数据。主要性能：加表精度<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&nbsp;1&times;10<st1:chmetcnv w:st=\"on\" unitname=\"g\" sourcevalue=\"4\" hasspace=\"False\" negative=\"True\" numbertype=\"1\" tcsc=\"0\">-4g<\/st1:chmetcnv><\/span><span style=\"font-size: 10.5pt; \">；光纤陀螺精度<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">(<\/span><span style=\"font-size: 10.5pt; \">漂移稳定性<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">)&le;1&deg;\/h<\/span><span style=\"font-size: 10.5pt; \">；标度固形线性度<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&le;5&times;10-4<\/span><span style=\"font-size: 10.5pt; \">。<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&nbsp;<br \/>');
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document.write('            2<\/span><span style=\"font-size: 10.5pt; \">、卫星通信系统<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&nbsp;<br \/>');
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document.write('            <\/span><span style=\"font-size: 10.5pt; \">卫星通信系统的作用是使电视信号上行传输到卫星，并由转发器下行传送到地面卫星接收装置。其主要设备有：编<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">\/<\/span><span style=\"font-size: 10.5pt; \">解码器、调制<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">\/<\/span><span style=\"font-size: 10.5pt; \">解调器、上<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">\/<\/span><span style=\"font-size: 10.5pt; \">下变频器、高功率放大器、双工器和低噪声放大器。<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&nbsp;<br \/>');
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document.write('            <\/span><b><span style=\"font-size: 10.5pt; \">二、<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&ldquo;<\/span><span style=\"font-size: 10.5pt; \">动中通<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&rdquo;<\/span><span style=\"font-size: 10.5pt; \">系统工作原理<\/span><span style=\"font-size: 10.5pt; font-family: Arial; \">&nbsp;<\/span><\/b><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \"><br \/>');
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document.write('            &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<\/span><span style=\"font-size: 10.5pt; \">载体在移动过程中，由于其姿态和地理位置发生变化，会引起原对准卫星天线偏离卫星，使通信中断，因此必须对载体的这些变化进行隔离，使天线不受影响并始终对准卫星。这就是天线稳定系统要解决的主要问题，也是移动载体进行不间断卫星通信的前提。<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&nbsp;<br \/>');
document.write('            &nbsp;&nbsp;&nbsp;&nbsp;&ldquo;<\/span><span style=\"font-size: 10.5pt; \">动中通<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&rdquo;<\/span><span style=\"font-size: 10.5pt; \">自动跟踪系统是在初始静态情况下，由<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">GPS<\/span><span style=\"font-size: 10.5pt; \">、经纬仪、捷联惯导系统测量出航向角、载体所在位置的经度和纬度及相对水平面的初始角，然后根据其姿态及地理位置、卫星经度自动确定以水平面为基准的天线仰角，在保持仰角对水平面不变的前提下转动方位，并以信号极大值方式自动对准卫星。在载体运动过程中，测量出载体姿态的变化，通过数学平台的运算，变换为天线的误差角，通过伺服机构调整天线方位角、俯仰角、极化角，保证载体在变化过程中天线对星在规定范围内，使卫星发射天线在载体运动中实时跟踪地球同步卫星。该系统跟踪方式有自跟踪和惯导跟踪两种。自跟踪是依靠卫星信标进行天线闭环伺服跟踪；惯导跟踪是利用陀螺惯导组合敏感载体的变化进行天线跟踪。这两种跟踪可根据现场情况自动切换。当系统对星完毕转入自动跟踪后，以自跟踪方式工作；与此同时，惯导系统也进入工作状态，并不断输出天线极化、方位和俯仰等数据。当由于遮挡或其它原因引起天线信标信号中断时，系统自动切换到惯导跟踪方式。同时，利用先进的移动卫星通信系统传输广播电视信号，达到现场转播效果。<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&nbsp;<br \/>');
document.write('            &nbsp;&nbsp;&nbsp;&nbsp;&ldquo;<\/span><span style=\"font-size: 10.5pt; \">动中通<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&rdquo;<\/span><span style=\"font-size: 10.5pt; \">车能在<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">20<\/span><span style=\"font-size: 10.5pt; \">～<\/span><st1:chmetcnv w:st=\"on\" unitname=\"km\/h\" sourcevalue=\"100\" hasspace=\"False\" negative=\"False\" numbertype=\"1\" tcsc=\"0\"><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">100km\/h<\/span><\/st1:chmetcnv><span style=\"font-size: 10.5pt; \">的行驶速度下通过卫星双向传送数字电视信号，保障运动载体在移动过程中不间断进行宽带多媒体卫星通信。各级路面载体最大行驶速度见附表。<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&nbsp;<br \/>');
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document.write('            <\/span><b><span style=\"font-size: 10.5pt; \">三、<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&ldquo;<\/span><span style=\"font-size: 10.5pt; \">动中通<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&rdquo;<\/span><span style=\"font-size: 10.5pt; \">在系统中的特点：<\/span><span style=\"font-size: 10.5pt; font-family: Arial; \">&nbsp;<\/span><\/b><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \"><br \/>');
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document.write('            (1)<\/span><span style=\"font-size: 10.5pt; \">在转播过程中采用自主跟踪方式跟踪卫星，充分利用了卫星通信覆盖区域大、抗干扰能力强、线路稳定的特点，可实现点对点、点对多点、点对主站移动卫星的通信；<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&nbsp;<br \/>');
document.write('            (2)&ldquo;<\/span><span style=\"font-size: 10.5pt; \">动中通<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&rdquo;<\/span><span style=\"font-size: 10.5pt; \">车具有灵活、机动的转播特点，能确保快速、实时的静态和动态现场直播；<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&nbsp;<br \/>');
document.write('            (3)<\/span><span style=\"font-size: 10.5pt; \">自动重捕时间短，驶出通信盲区后能快速恢复通信；<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&nbsp;<br \/>');
document.write('            (4)<\/span><span style=\"font-size: 10.5pt; \">与<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">OFDM&ldquo;<\/span><span style=\"font-size: 10.5pt; \">无方向<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&rdquo;<\/span><span style=\"font-size: 10.5pt; \">移动微波设备相比，<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&ldquo;<\/span><span style=\"font-size: 10.5pt; \">动中通<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&rdquo;<\/span><span style=\"font-size: 10.5pt; \">车无需收、发设备操作人员在恶劣环境条件下工作，节约了人力、物力，而且减小了电磁辐射污染；<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&nbsp;<br \/>');
document.write('            (5)<\/span><span style=\"font-size: 10.5pt; \">信号传输过程的节点减少，提高了转播质量和可靠性；<\/span><span lang=\"EN-US\" style=\"font-size: 10.5pt; font-family: Arial; \">&nbsp;<br \/>');
document.write('            (6)<\/span><span style=\"font-size: 10.5pt; \">能降低大范围、复杂场景直播过程的运行成本。<\/span><\/p>');
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