查找与低功耗蓝牙设备的 RSSI 值的距离 [英] Finding distance from RSSI value of Bluetooth Low Energy enabled device
问题描述
我正在研究低功耗蓝牙概念项目.我正在获取 RSSI 值介于 1 和 100 之间.当我移动标签时，RSSI 值随着外围设备远离 iPhone 而增加，并随着它靠近而减小.
I am working on Bluetooth low energy concept project. I am getting the RSSI value between 1 and 100. As I move the tag the RSSI value increase as the peripheral moves away from the iPhone and decreases as it moves closer.
有人可以帮助我根据 RSSI 值获得 iPhone 和蓝牙标签之间的准确距离吗?有没有可用的公式?
Can anybody help me to get exact distance between the iPhone and the Bluetooth tag based on the RSSI value? Are there any available formulas?
借助这种蓝牙低功耗委托方法，我正在获取设备的 RSSI 值:
I am getting the RSSI value of the device with the help of this bluetooth Low energy delegate method:
- (void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral
*)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI
推荐答案
我在另一个帖子中回答了这个问题，这里重复一遍.
I answered this in another thread, repeating it here.
在视线范围内(没有导致 RSSI 变化的障碍物)，-6dB 似乎是距离的两倍.
In line-of-sight (no obstacles causing change in RSSI), -6dB seems to be double the distance.
如果你在 1m 距离读取 RSSI -40dB，那么 2m 给出 -46dB，4m 给出 -52dB，8m 给出 -58dB，16m 给出 -64dB.
If you at 1m distance read RSSI -40dB then 2m gives -46dB, 4m gives -52dB, 8m gives -58dB, 16m gives -64dB.
你不能得到一个准确的位置，只能得到一个圆形的最大距离.
You can not get an exact position, only a circular maximum distance.
在 2-3 台或更多设备上使用三角测量可以获得更准确的定位结果.您可以完全从广告包中获取此信息，但您必须禁用扫描 -> 启用扫描或告诉 iOS CoreBluetooth 报告所有广告包.
Using triangulation with 2-3 or more devices you get a much more accurate positioning result. You can get this purely from Advertisement packages but you must either Disable scan -> Enable scan or tell iOS CoreBluetooth to report all adv packages.
在前台模式下你可以这样做，但在后台模式下你不能得到所有的 adv 包.您必须连接并读取 RSSI 才能在后台执行此操作.
In foreground mode you can do this but in background mode you can't get all adv packages. You must connect and read RSSI to do it in the background.
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