他们不得不在隧道入口处安置一名信号员站岗。
是的，他们只会反弹得更远。如果隧道够长，FM的信号会直到你从隧道那一头终点出来时才消失。
Yep. Of course, they only bounce so far. If the tunnel is long enough, even FM stations fade out until you come out the other end.
为什么在隧道中调频广播比调幅广播的信号要好一点？
目前手机信号将覆盖整个站台以及夹层，但进入隧道后就只能覆盖很小一段距离了。
The signals will cover platforms and mezzanines but will extend only a short distance into tunnels.
对于城市车辆GPS导航来说，其很大的一个缺点是跟踪卫星的信号常常由于建筑物、隧道及树木等的遮挡而使GPS的定位精度大大降低，甚至无法进行正常的导航和定位。
GPS can not be used continuously for city vehicle navigation due to the loss of satellite signals by obstructions from buildings, tunnels and trees etc and it leads to low positioning accuracy.
该天线结构简单，重量轻、设计容易、制造成本低廉，适合隧道、高速公路、长形建筑等狭长区域的信号覆盖。
The antenna has a simple structure, light weight, easier design, lower cost, fit for the signal cover of the narrow and long region such as tunnel, expressway, long buildings.
程序还会在旅客过桥或过隧道的时候加速，以防其失去信号。
The app also speeds up after you go under Bridges and tunnels in case you lose signal.
而在某些特殊的场景，如隧道或高楼路段，卫星信号较弱甚至无信号。
In some special scenarios, such as road tunnels or tall buildings, the satellite signal is weak or indiscernible.
本文对隧道覆盖中涉及的信号源选择、天馈线分布方式选择进行了系统的归纳和研究，提出了不同长度隧道的典型解决方案。
The dissertation collate and study the source selection, antenna pattern of distribution involved in tunnel coverage, put forward different solutions to the typical length of the tunnel.
结果表明，隧道中信号传输的时延扩展和信号的衰减均与载波频率有关。
Simulation results showed that, with the same roughness of a tunnel, both the delay spread and the signal attenuation varied with the carrier frequency.
在城市的建筑物和隧道里，一般无线信号很容易丧失，他们已经设计了系统工作在恶劣的环境-如城市，例如-在信号可以很容易丧失的建筑物和隧道。
They've designed the system to work in harsh radio environments - like cities, for example - where signals can easily be lost among the buildings and tunnels.
系统试运行表明，该系统能自动检测隧道内的故障停车并发出报警信号。
Experiments and trial operation show that the system can automatically detect the trouble parking in tunnel and give an alarm.
系统试运行表明，该系统能自动检测隧道内的故障停车并发出报警信号。
Experiments and trial operation show that the system can automatically detect the trouble parking in tunnel and give an alarm.
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