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V**R
发帖数: 161 | 1 首先声明，绝对没有不良用途。就是希望在科研方面用。我也不是搞无线通讯的，所以
问的问题有可能
挺傻的。
有这样一个需求，希望在某个微环境下（比如一个直径200米的圆），对进入此区域的
手机信号进行轨迹
跟踪，不是GPS跟踪，而是那种被动方式的，手机持有者甚至都不知道的那种。
以前听说过一种叫network-based location,但据说这个在2G时代误差能有几百米呢，
不太适合。
不知道到了3G下是不是这个单纯靠无线网络定位的方式准确度大很多了？
另外，我不太了解无线通讯方面，这个伪基站能否是被动方式的？能否实现了我上述的
目标呢？
还有价格，我因为不知道需要用啥硬件来搭建这个东西所以对价格也一无所知的。但看
了看国内卖的功
能类似主要用于公检法的那种工具，似乎几百的都有。搭建一个功能最简单的伪基站最
少多少钱呢？我
不想去拦截什么语音信号，只是想匿名的知道手机持有者的轨迹。
鞠躬，谢谢。 | g*****e
发帖数: 87 | 2 In the GSM system, the location is roughly calculated based on the Timing
advance: Drawing a circle with each neighboring BTS as center with radius
based on TA. The intersection of three circles are more or less of the
location of the MS as each BTS longitude and latitude are known.
UMTS is based on the propagation delay, roughly the same as GSM with more
accuracy. I remember it has something to do short symbol times.
Usually the law enforcement has access to the location system and can
retrieve the location information real time.
I don't believe you can build a BTS/NodeB to fool the UE or MS as it won't
camp on your BTS/NodeB if you don't broadcast the proper network id. |
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