如何使用Wi-Fi获得距离 [英] how to get distance using Wi-Fi
问题描述
我想找到使用wi-fi的距离并在iPhone上绘制地图上的标记。
I want to find the distance using wi-fi and plot the marker on map in iPhone.
那么我能得到的任何想法或代码？
So any idea or code i can get for that?
推荐答案
在第一次阅读你的问题时，我假设你指的是到接入点的距离。写了一堆关于那个，我意识到你可能意味着别的东西。如果这是你的意思，继续阅读......
Upon first reading your question, i was under the assumption you were referring to distance to an access point. After writing a bunch about that, i realized you might mean something else. In case that is what you mean, keep reading...
鉴于你的配置：
- 单个固定接收器（您的手机无需修复，但如果您正在寻找瞬时测量值，则可以有效修复）
- 单个固定基站（接入点）
- 接收器上的全向天线
- 802.11 b / g协议
- a single fixed receiver (your phone doesn't have to be fixed, but it is effectively fixed if you're looking for instantaneous measurements)
- a single fixed base station (the access point)
- an omnidirectional antenna on the receiver
- 802.11 b/g protocol
这是无法做到的。即使您在 PHY 级别工作，这也是一个不可能解决的问题。为了使其更加可行，您需要三角测量接收器相对于两个接收器的位置（但是最好是更多）基站。即使然后这仍然是一个难题。 RF波以光速传播，因此使用中继技术测量往返信号传播延迟将不会提供良好的准确性（接收器必须非常快速地操作，然后 multipath 问题...）。再说一遍，假设你基本上都在构建自己的射频硬件，显然你不打算为iPhone做这件事。
This cannot be done. Even if you were working at the PHY level, this is an impossible problem to solve. To make it slightly more feasible, you need to triangulate the position of your receiver relative to two (but preferably more) base stations. Even then this is still a hard problem. RF waves travel at the speed of light, so using relay techniques to measure round-trip signal propagation delay won't give good accuracy (the receivers have to operate extremely fast, and then there's multipath problems...). Again, this is all assuming you're basically building your own RF hardware, which obviously you're not about to do for the iPhone.
追踪你的最佳选择基站的位置是在您改变手机位置时记录WiFi信号强度。通过'改变位置'，你基本上必须扫过该区域。通过一些良好的启发式算法和处理非距离相关信号衰减的稳健性，您可以获得不错的精度（可能大约10米）。
Your best bet to track down the location of a base station is to record the WiFi signal strength as you change the position of the phone. By 'change the position', you would essentially have to sweep around the area. With some good heuristics, and robustness to handle non-distance related signal degradation, you could achieve decent accuracy (probably on the order of 10 meters).
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