/// <summary>
/// Compute the position given the receivings
/// </summary>
internal static Position triangulate(List <Packet.Reception> receivings, DateTime receptiontime)
{
Position p = new Position(Vector2D.Zero, receivings[0].ReceivingStation.location.room);
Vector2D accumulator = new Vector2D(Vector2D.Zero);
p.positionDate = receptiontime;
String tag = "";
if (receivings.Count() > 2)
{
double minrssi = 0;
double avgrssi = 0;
double vote = 0;
foreach (Packet.Reception pr in receivings)
{
tag += (Environment.NewLine + pr.RSSI + " " + pr.ReceivingStation.NameMAC);
minrssi = pr.RSSI < minrssi ? pr.RSSI : minrssi;
avgrssi += pr.RSSI;
double weight = Math.Pow(Math.E, (pr.RSSI + 25) / 10);
accumulator = accumulator.Add(pr.ReceivingStation.location.MultiplyScalar(weight));
vote += weight;
}
avgrssi /= receivings.Count();
accumulator = accumulator.DivideScalar(vote).Clip(Vector2D.Zero, p.room.size);
tag += Environment.NewLine + "avg: " + accumulator.X + " " + accumulator.Y;
if (avgrssi < -105 || (avgrssi < -90 && minrssi < -70))
{
p = new Position(0, 0, Room.externRoom);
}
else
{
if (receivings.Count() == 3)
{
Vector2D tr = triangulate_circles(receivings);
if (tr != null)
{
//tag += Environment.NewLine + "tri: " + tr.X + " " + tr.Y;
accumulator = accumulator.MultiplyScalar(0.87).Add(tr.Clip(Vector2D.Zero, p.room.size).MultiplyScalar(0.13));
}
}
p._Import(accumulator);
}
}
else
{
p.uncertainity = UNCERTAIN_POSITION + 1;
}
p.tag = tag;
return(p);
}