org.altbeacon.beacon.distance

Class CurveFittedDistanceCalculator

java.lang.Object

org.altbeacon.beacon.distance.CurveFittedDistanceCalculator

All Implemented Interfaces:

DistanceCalculator

public class CurveFittedDistanceCalculator
extends Object
implements DistanceCalculator

This class estimates the distance between the mobile device and a BLE beacon based on the measured RSSI and a txPower calibration value that represents the expected RSSI for an iPhone 5 receiving the signal when it is 1 meter away. This class uses a best-fit curve equation with configurable coefficients. The coefficients must be supplied by the caller and are specific to the Android device being used. See the ModelSpecificDistanceCalculator for more information on the coefficients. Created by dyoung on 8/28/14.

Field Summary

Fields

Modifier and Type	Field and Description
static String	TAG

Constructor Summary

Constructors

Constructor and Description
CurveFittedDistanceCalculator(double coefficient1, double coefficient2, double coefficient3) Construct a calculator with coefficients specific for the device's signal vs.

Method Summary

Modifier and Type	Method and Description
double	calculateDistance(int txPower, double rssi) Calculated the estimated distance in meters to the beacon based on a reference rssi at 1m and the known actual rssi at the current location

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

TAG

public static final String TAG

See Also:

Constant Field Values

Constructor Detail

CurveFittedDistanceCalculator

public CurveFittedDistanceCalculator(double coefficient1,
                                     double coefficient2,
                                     double coefficient3)

Construct a calculator with coefficients specific for the device's signal vs. distance

Parameters:

coefficient1 -

coefficient2 -

coefficient3 -

Method Detail

calculateDistance

public double calculateDistance(int txPower,
                                double rssi)

Calculated the estimated distance in meters to the beacon based on a reference rssi at 1m and the known actual rssi at the current location

Specified by:

calculateDistance in interface DistanceCalculator

Parameters:

txPower -

rssi -

Returns:

estimated distance