3辺測定法:3点座標と3点までの距離で4点目の位置に戻る
4793 ワード
public class IBeaconLocation {
//
public static double calculateAccuracy(iBeaconClass.iBeacon beacon) {
int txPower = beacon.txPower;
double rssi = beacon.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;
}
}
//
// , 4
public double[] calcPhonePosition(double x1, double y1, double d1,
double x2, double y2, double d2,
double x3, double y3, double d3) {
double[] d = {0.0, 0.0};
double a11 = 2 * (x1 - x3);
double a12 = 2 * (y1 - y3);
double b1 = Math.pow(x1, 2) - Math.pow(x3, 2)
+ Math.pow(y1, 2) - Math.pow(y3, 2)
+ Math.pow(d3, 2) - Math.pow(d1, 2);
double a21 = 2 * (x2 - x3);
double a22 = 2 * (y2 - y3);
double b2 = Math.pow(x2, 2) - Math.pow(x3, 2)
+ Math.pow(y2, 2) - Math.pow(y3, 2)
+ Math.pow(d3, 2) - Math.pow(d2, 2);
d[0] = (b1 * a22 - a12 * b2) / (a11 * a22 - a12 * a21);
d[1] = (a11 * b2 - b1 * a21) / (a11 * a22 - a12 * a21);
return d;
}
//double
public int doubleRound(double num) {
BigDecimal b = new BigDecimal(num);
num = b.setScale(0, BigDecimal.ROUND_HALF_UP).doubleValue();
return (int) num;
}
}