altbeacon - 计算距离的常量 [英] altbeacon - constants for calculating distance
问题描述
我在写一篇室内使用导航iBeacons我的学士论文。对于这一点，我使用三边测量来找到我的位置。我一直在使用了android灯塔库，也就是现在被称为AltBeacon库来检测信标和计算距离。我注意到，我得到的距离不准确，并经过一番搜索在这里，我遇到了一个职位从DavidYoung说，因为大部分的设备有不同的蓝牙天线，我将不得不考虑到这一点时，即时通讯计算距离。< BR>
该AltBeacon库计算这样的距离（从DavidYoungs <一个取href="http://stackoverflow.com/questions/21338031/radius-networks-ibeacon-ranging-fluctuation/21340147#21340147">post):
I'm writing my bachelor thesis on indoor navigation using iBeacons. For this i use trilateration to find my position. I've been using the android beacon library, which is now known as the AltBeacon library to detect beacons and calculate the distance. I noticed, that the distances i get aren't that accurate and after some searching here, i came across a post from DavidYoung saying that because most device have different Bluetooth antennas i would have to take that into account when im calculating the distance.
The AltBeacon library calculates the distance like this (taken from DavidYoungs post):
protected static double calculateAccuracy(int txPower, double rssi) {
if (rssi == 0) {
return -1.0; // if we cannot determine accuracy, return -1.
}
double ratio = rssi*1.0/txPower;
if (ratio < 1.0) {
return Math.pow(ratio,10);
}
else {
double accuracy = (0.89976)*Math.pow(ratio,7.7095) + 0.111;
return accuracy;
}
}
我现在的问题是：
我怎么计算这些值（0.89976，7.7095，0.111）为我的LG G2与RSSI测量从信标某些米的间隔？
我发现这的作为与测量值的示例计算系数中。
My question now is:
how do i calculate these values (0.89976, 7.7095, 0.111) for my Lg G2 with RSSI measurements at certain meter intervals from the beacon?
I found this as an example for measurement values with the calculated coefficent.
5的Nexus远程数据
Nexus 5 Distance Data
仪表RSSI
0.25 -41
0.5 -43
1 -49
2 -65
3 -58
4 -57
5 -67
6 -67
7 -77
8 -70
9 -69
10 -75
12 -72
14 -72
16 -78
18 -83
20 -81
25 -81
30 -75
40 -83
Meters RSSI
0.25 -41
0.5 -43
1 -49
2 -65
3 -58
4 -57
5 -67
6 -67
7 -77
8 -70
9 -69
10 -75
12 -72
14 -72
16 -78
18 -83
20 -81
25 -81
30 -75
40 -83
Android设备：
版本：4.4.2
BUILD_NUMBER：LPV79
型号：Nexus的5
制造商：LG电子
灯塔信息：
RadBeacon标签
每秒广告：10
发射功率：最大
IPhone 5S平均RSSI @1米：-51
Android device:
version: 4.4.2
build_number: LPV79
model: Nexus 5
manufacturer: LGE
Beacon Info:
RadBeacon Tag
Advertisements per second: 10
Transmit Power: Max
IPhone 5s Average RSSI @1m: -51
计算这些值距离公式的系数：
截取：0.1820634
乘数：0.8229884
功率：6.6525179
Distance formula coefficients calculated for these values:
Intercept: 0.1820634
Multiplier: 0.8229884
Power: 6.6525179
术语截距表明线性回归，但是当我把值转换为线性回归计算器，它给了我，是远不及这些值的结果。
我希望你能帮助我，我的问题是清楚不过了:)
The term intercept suggests linear regression, but when i put the values into a linear regression calculator it gave me results that were nowhere near those values.
I hope you can help me and that my question is clear enough :)
推荐答案
有很多种类的公式，你可以用做一个最合适的回归时。距离计算中，我们使用的功率曲线，拟合到所支持的自由R统计软件包。你可以阅读更多关于如何做到这一点的位置：
There are many kinds of formulas you can use when doing a best-fit regression. For distance calculations, we use a power curve, fitting to which is supported by the free R statistical package. You can read more about how to do this here:
https://github.com/AltBeacon/android-beacon-library/问题/ 47
尽管取得了设备特定的公式可以帮助你获得更好的距离估计，多是从三边输出看到的错误大概是从信号中的噪声，减弱障碍和多路径。要知道，即使是设备特定的公式，信标范围是不精确和precision恶化进一步你远离设备。为了减轻这些影响，空间的信标尽可能清晰的视线移动设备，如果可能的。
While getting a device-specific formula will help you get better distance estimates, much of the error you are seeing from trilateration output is probably from signal noise, attenuating obstructions and multipath. Understand that even with a device-specific formula, beacon ranging is inexact and precision gets worse the further you are away from the device. To mitigate these effects, space your beacons as closely as possible with clear line of sight to the mobile device if possible.
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