AccessPoint.java :  » App » pocketcampus » org » pocketcampus » positioning » Android Open Source

/*
 ********************* [ P O C K E T C A M P U S ] *****************
 * [    LICENCE    ]   see "licence"-file in the root directory
 * [   MAINTAINER  ]  tarek.benoudina@epfl.ch
 * [     STATUS    ]    stable
 *
 **************************[ C O M M E N T S ]**********************
 *
 * Represents an Acess Point.
 *
 *******************************************************************
 */



package org.pocketcampus.positioning;

import android.net.wifi.ScanResult;

import org.pocketcampus.map.Position;

public class AccessPoint {
  private Position position;
  private String SSID;
  private int signalLevel;
  private String name;
  private int radiatedPower;
  
  public AccessPoint(ScanResult sr, String apName, Position pos) {
    SSID = sr.SSID;
    signalLevel = 100 + sr.level;   // sr.level < 0
    name = apName;
    position = pos;
    radiatedPower = 100;  // cisco value 
  }

  public Position position() {
    return position;
  }
  
  public int getSignalLevel() {
    return signalLevel;
  }
  
  @Override
  public String toString() {
    String apName = "??";
    Position pos = new Position(0, 0, 0);
    
    if(name != null) {
      apName = name;
    }
    
    if(position != null) {
      pos = position;
    }
    
    return SSID + ", "+apName+": ("+ pos.getLat() + ";"+ pos.getLon() +";"+pos.getLevel()+"), "+ signalLevel;
  }
  
  
//   to get distance to the AP, we assume that we now the power radiated of the AP
//  Radiated Power (max signal) added to the AP class,
//  in order to compute the distance from AP,
//  supposing ours APs are Isotrop Antenna.
//  so RSS = Power/4*PI*R^2 (R is the distance)
  
  public double getDistance(){
    double distance = 0;
    double pi = Math.PI;
    int power = this.radiatedPower;
    int lev = this.getSignalLevel();
    distance = Math.sqrt((power/4*pi*lev));
    
    
    return distance;
  }
  
  
  public int getEstimatedDistance(){
    int distance = 0;
    if(this.getSignalLevel()>55)
      distance = 4;
    else if((this.getSignalLevel()>40)&&(this.getSignalLevel()<=55))
      distance = 8;
    else distance = 12;
    return distance;
  }
  
  public void setSignalLevel(int level){
    this.signalLevel = level;
  }
  
  
  public String getSSID(){
    return this.SSID;
  }
  
  public String getName(){
    return this.name;
  }
}