private static AisData? DecodeAisDataMessage(string dataMessage)
{
StringBuilder sb = new StringBuilder();
foreach (char c in dataMessage)
{
int i = c;
i -= 48;
if (i > 40)
i -= 8;
for (int j = 5; j >= 0; j--)
{
if (((i >> j) & 1) == 1)
sb.Append("1");
else
sb.Append("0");
}
}
if (sb.Length < 89 + 27)
return null;
string bitString = sb.ToString();
long lat = TreatAsSigned(bitString.Substring(89, 27));
long lon = TreatAsSigned(bitString.Substring(61, 28));
AisData aisObj = new AisData();
aisObj.Latitude = lat / 600000.0;
aisObj.Longitude = lon / 600000.0;
aisObj.TransponderID = Convert.ToInt32(bitString.Substring(8, 30), 2);
aisObj.RateOfTurn = Convert.ToInt32(bitString.Substring(42, 8), 2);
aisObj.SpeedOverGround = Convert.ToInt32(bitString.Substring(50, 10), 2) / 10;
aisObj.CourseOverGround = Convert.ToInt32(bitString.Substring(116, 12), 2);
aisObj.PositionAccuracy = Convert.ToInt32(bitString.Substring(60, 1), 2);
aisObj.TrueHeading = Convert.ToInt32(bitString.Substring(128, 9), 2);
return aisObj;
}
public static void DumpAis(AisData aisObj)
{
Console.WriteLine("Transponder MMSI: " + aisObj.TransponderID);
Console.WriteLine("Latitude: " + aisObj.Latitude);
Console.WriteLine("Longitude: " + aisObj.Longitude);
Console.WriteLine("SpeedOverGround: " + aisObj.SpeedOverGround);
Console.WriteLine("CourseOverGround: " + aisObj.CourseOverGround);
Console.WriteLine("PositionAccuracy: " + aisObj.PositionAccuracy);
Console.WriteLine("TrueHeading: " + aisObj.TrueHeading);
Console.WriteLine("RateOfTurn: " + aisObj.RateOfTurn);
}
public String AddOrUpdateAisTransponder(AisData aisData)
{
Console.WriteLine("Received transponder data: " + aisData.TransponderID);
lock (_knownTransponders)
{
if (_knownTransponders.ContainsKey(aisData.TransponderID))
_knownTransponders[aisData.TransponderID] = aisData;
else
_knownTransponders.Add(aisData.TransponderID, aisData);
}
return "OK";
}
