ExampleDecoder.java

package org.opensky.example;

/*
 *  This file is part of org.opensky.libadsb.
 *
 *  org.opensky.libadsb is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  org.opensky.libadsb is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with org.opensky.libadsb.  If not, see <http://www.gnu.org/licenses/>.
 */

import org.opensky.libadsb.*;
import org.opensky.libadsb.exceptions.BadFormatException;
import org.opensky.libadsb.exceptions.UnspecifiedFormatError;
import org.opensky.libadsb.msgs.*;

import java.util.Scanner;

/**
 * ADS-B decoder example: It reads STDIN line-by-line. It should be fed with
 * comma-separated timestamp, receiver latitude, receiver longitude and the
 * raw Mode S/ADS-B message. Receiver coordinates can be omitted. In that
 * case, surface position messages cannot be decoded properly and plausibility
 * checks for positions are limited. 
 * 
 * Example input:
 * 
 * 1,8d4b19f39911088090641010b9b0
 * 2,8d4ca513587153a8184a2fb5adeb
 * 3,8d3413c399014e23c80f947ce87c
 * 4,5d4ca88c079afe
 * 5,a0001838ca3e51f0a8000047a36a
 * 6,8d47a36a58c38668ffb55f000000
 * 7,5d506c28000000
 * 8,a8000102fe81c1000000004401e3
 * 9,a0001839000000000000004401e3
 * 
 * @author Matthias Schäfer (schaefer@opensky-network.org)
 * @author Markus Fuchs (fuchs@opensky-network.org)
 */
public class ExampleDecoder {
	// The ModeSDecoder does all the magic for us
	private ModeSDecoder decoder = new ModeSDecoder();

	/**
	 *
	 * @param timestamp in milliseconds since epoch
	 * @param raw Mode S messages as hex string
	 * @param receiver the location of the receiver for sanity checks on decoded positions (optional)
	 */
	public void decodeMsg(long timestamp, String raw, Position receiver) {
		ModeSReply msg;
		try {
			msg = decoder.decode(raw);
		} catch (BadFormatException e) {
			System.out.println("Malformed message! Skipping it. Message: "+e.getMessage());
			return;
		} catch (UnspecifiedFormatError e) {
			System.out.println("Unspecified message! Skipping it...");
			return;
		}

		String icao24 = tools.toHexString(msg.getIcao24());

		// check for erroneous messages; some receivers set
		// parity field to the result of the CRC polynomial division
		if (tools.isZero(msg.getParity()) || msg.checkParity()) { // CRC is ok

			// now check the message type
			switch (msg.getType()) {
			case ADSB_AIRBORN_POSITION_V0:
			case ADSB_AIRBORN_POSITION_V1:
			case ADSB_AIRBORN_POSITION_V2:
				AirbornePositionV0Msg ap0 = (AirbornePositionV0Msg) msg;
				System.out.print("["+icao24+"]: ");

				// use CPR to decode position
				// CPR needs at least 2 positions or a reference, otherwise we get null here
				Position c0 = decoder.decodePosition(timestamp, ap0, receiver);
				if (c0 == null)
					System.out.println("Cannot decode position yet.");
				else
					System.out.println("Now at position (" + c0.getLatitude() + "," + c0.getLongitude() + ")");
				System.out.println("          Horizontal containment radius limit/protection level: " +
						ap0.getHorizontalContainmentRadiusLimit() + " m");

				if (ap0.isBarometricAltitude())
					System.out.println("          Altitude (barom.): "+ (ap0.hasAltitude() ? ap0.getAltitude() : "unknown") +" ft");
				else
					System.out.println("          Height (geom.): "+ (ap0.hasAltitude() ? ap0.getAltitude() : "unknown") +" ft");

				Integer geoMinusBaro = decoder.getGeoMinusBaro(msg);
				if (ap0.hasAltitude() && ap0.isBarometricAltitude() && geoMinusBaro != null) {
					System.out.println("          Height (geom.): " + ap0.getAltitude() + geoMinusBaro + " ft");
				}

				System.out.println("          Navigation Integrity Category: " + ap0.getNIC());
				System.out.println("          Surveillance status: " + ap0.getSurveillanceStatusDescription());

				// we want to inspect fields for ADS-B of different versions
				switch(msg.getType()) {
					case ADSB_AIRBORN_POSITION_V0:
						// NACp and SIL for newer ADS-B versions contained in operational status message
						System.out.println("          Navigation Accuracy Category for position (NACp): " + ap0.getNACp());
						System.out.println("          Position Uncertainty (based on NACp): " + ap0.getPositionUncertainty());
						System.out.println("          Surveillance Integrity Level (SIL): " + ap0.getSIL());
						break;
					case ADSB_AIRBORN_POSITION_V1:
						AirbornePositionV1Msg ap1 = (AirbornePositionV1Msg) msg;
						System.out.println("          NIC supplement A set: " + ap1.hasNICSupplementA());
						break;
					case ADSB_AIRBORN_POSITION_V2:
						AirbornePositionV2Msg ap2 = (AirbornePositionV2Msg) msg;
						// NIC supplement A contained in operational status messages is set by the decoder if present
						System.out.println("          NIC supplement A set: " + ap2.hasNICSupplementA());
						System.out.println("          NIC supplement B set: " + ap2.hasNICSupplementB());
						break;
				}
				break;
			case ADSB_SURFACE_POSITION_V0:
			case ADSB_SURFACE_POSITION_V1:
			case ADSB_SURFACE_POSITION_V2:
				SurfacePositionV0Msg sp0 = (SurfacePositionV0Msg) msg;
				System.out.print("["+icao24+"]: ");

				Position sPos0 = decoder.decodePosition(timestamp, sp0, receiver);
				// decode the position if possible; prior position needed
				if (sPos0 == null)
					System.out.println("Cannot decode position yet or no reference available (yet).");
				else
					System.out.println("Now at position (" + sPos0.getLatitude() + "," + sPos0.getLongitude() + ")");

				System.out.println("          Horizontal containment radius limit/protection level is " +
						sp0.getHorizontalContainmentRadiusLimit() + "m");
				if (sp0.hasValidHeading())
					System.out.println("          Heading: " + sp0.getHeading() + "°");
				System.out.println("          Airplane is on the ground.");

				if (sp0.hasGroundSpeed()) {
					System.out.println("          Ground speed: " + sp0.getGroundSpeed() + "kt");
					System.out.println("          Ground speed resolution: " + sp0.getGroundSpeedResolution() + "kt");
				}

				// we want to inspect fields for ADS-B of different versions
				switch(msg.getType()) {
					case ADSB_SURFACE_POSITION_V0:
						// NACp and SIL for newer ADS-B versions contained in operational status message
						// Use the following only with version 0 as the others are more accurate
						System.out.println("          Navigation Accuracy Category for position (NACp): " + sp0.getNACp());
						System.out.println("          Position Uncertainty (based on NACp): " + sp0.getPositionUncertainty() + "m");
						System.out.println("          Surveillance Integrity Level (SIL): " + sp0.getSIL());
						break;
					case ADSB_SURFACE_POSITION_V1:
						SurfacePositionV1Msg sp1 = (SurfacePositionV1Msg) msg;
						System.out.println("          NIC supplement A set: "+sp1.hasNICSupplementA());
						break;
					case ADSB_SURFACE_POSITION_V2:
						SurfacePositionV2Msg sp2 = (SurfacePositionV2Msg) msg;
						// NIC supplement C contained in operational status messages is set by the decoder if present
						System.out.println("          NIC supplement A set: "+sp2.hasNICSupplementA());
						System.out.println("          NIC supplement C set: "+sp2.hasNICSupplementC());
						break;
				}

				break;
			case ADSB_EMERGENCY:
				EmergencyOrPriorityStatusMsg status = (EmergencyOrPriorityStatusMsg) msg;
				System.out.println("["+icao24+"]: "+status.getEmergencyStateText());
				System.out.println("          Mode A code is "+status.getModeACode()[0]+
						status.getModeACode()[1]+status.getModeACode()[2]+status.getModeACode()[3]);
				break;
			case ADSB_AIRSPEED:
				AirspeedHeadingMsg airspeed = (AirspeedHeadingMsg) msg;
				System.out.println("["+icao24+"]: Airspeed: "+
						(airspeed.hasAirspeedInfo() ? airspeed.getAirspeed()+" kt" : "unkown"));

				if (decoder.getAdsbVersion(msg) == 0) {
					// version 0 flag indicates true or magnetic north
					System.out.println("          Heading: " + airspeed.getHeading() + "° relative to " +
							(airspeed.hasHeadingStatusFlag() ? "magnetic north" : "true north"));
				} else {
					// version 1+ flag indicates if heading is available at all
					System.out.println("          Heading: "+
							(airspeed.hasHeadingStatusFlag() ? airspeed.getHeading()+"°" : "unkown"));
				}

				if (airspeed.hasVerticalRateInfo())
					System.out.println("          Vertical rate: "+
							(airspeed.hasVerticalRateInfo() ? airspeed.getVerticalRate()+" ft/min" : "unkown"));
				break;
			case ADSB_IDENTIFICATION:
				IdentificationMsg ident = (IdentificationMsg) msg;
				System.out.println("["+icao24+"]: Callsign: "+new String(ident.getIdentity()));
				System.out.println("          Category: "+ident.getCategoryDescription());
				break;
			case ADSB_STATUS_V0:
				OperationalStatusV0Msg opstat0 = (OperationalStatusV0Msg) msg;
				System.out.println("["+icao24+"]: Using ADS-B version "+opstat0.getVersion());
				System.out.println("          Has operational TCAS: "+ opstat0.hasOperationalTCAS());
				System.out.println("          Has operational CDTI: "+ opstat0.hasOperationalCDTI());
				break;
			case ADSB_AIRBORN_STATUS_V1:
			case ADSB_AIRBORN_STATUS_V2:
				AirborneOperationalStatusV1Msg opstatA1 = (AirborneOperationalStatusV1Msg) msg;
				System.out.println("["+icao24+"]: Using ADS-B version "+opstatA1.getVersion());
				System.out.println("          Barometric altitude cross-checked: "+opstatA1.getBarometricAltitudeIntegrityCode());
				System.out.println("          Gemoetric vertical accuracy: "+opstatA1.getGeometricVerticalAccuracy()+"m");

				if (opstatA1.getHorizontalReferenceDirection())
					System.out.println("          Horizontal reference: true north");
				else
					System.out.println("          Horizontal reference: true north");
				System.out.println("          Navigation Accuracy Category for position (NACp): " + opstatA1.getNACp());
				System.out.println("          Position Uncertainty (based on NACp): " + opstatA1.getPositionUncertainty());
				System.out.println("          Has NIC supplement A: " + opstatA1.hasNICSupplementA());
				System.out.println("          Surveillance/Source Integrity Level (SIL): " + opstatA1.getSIL());
				System.out.println("          System design assurance: " + opstatA1.getSystemDesignAssurance());
				System.out.println("          Has 1090ES in: " + opstatA1.has1090ESIn());
				System.out.println("          IDENT switch active: " + opstatA1.hasActiveIDENTSwitch());
				System.out.println("          Has operational TCAS: " + opstatA1.hasOperationalTCAS());
				System.out.println("          Has TCAS resolution advisory: " + opstatA1.hasTCASResolutionAdvisory());
				System.out.println("          Has UAT in: " + opstatA1.hasUATIn());
				System.out.println("          Uses single antenna: " + opstatA1.hasSingleAntenna());
				System.out.println("          Supports air-referenced velocity reports: " + opstatA1.hasAirReferencedVelocity());

				// SIL supplement in version 2
				if (msg instanceof AirborneOperationalStatusV2Msg) {
					System.out.println("          Has SIL supplement: " + ((AirborneOperationalStatusV2Msg) msg).hasSILSupplement());
				}

				break;
			case ADSB_SURFACE_STATUS_V1:
			case ADSB_SURFACE_STATUS_V2:
				SurfaceOperationalStatusV1Msg opstatS1 = (SurfaceOperationalStatusV1Msg) msg;

				System.out.println("["+icao24+"]: Using ADS-B version "+opstatS1.getVersion());
				System.out.println("          Gemoetric vertical accuracy: "+opstatS1.getGeometricVerticalAccuracy()+"m");

				if (opstatS1.getHorizontalReferenceDirection())
					System.out.println("          Horizontal reference: true north");
				else
					System.out.println("          Horizontal reference: true north");
				System.out.println("          Navigation Accuracy Category for position (NACp): " + opstatS1.getNACp());
				System.out.println("          Position Uncertainty (based on NACp): " + opstatS1.getPositionUncertainty());
				System.out.println("          Has NIC supplement A: " + opstatS1.hasNICSupplementA());
				System.out.println("          Has NIC supplement C: " + opstatS1.getNICSupplementC());
				System.out.println("          Surveillance/Source Integrity Level (SIL): " + opstatS1.getSIL());
				System.out.println("          System design assurance: " + opstatS1.getSystemDesignAssurance());
				System.out.println("          Has 1090ES in: " + opstatS1.has1090ESIn());
				System.out.println("          IDENT switch active: " + opstatS1.hasActiveIDENTSwitch());
				System.out.println("          Has TCAS resolution advisory: " + opstatS1.hasTCASResolutionAdvisory());
				System.out.println("          Has UAT in: " + opstatS1.hasUATIn());
				System.out.println("          Uses single antenna: " + opstatS1.hasSingleAntenna());
				System.out.println("          Airplane length: " + opstatS1.getAirplaneLength() + "m");
				System.out.println("          Airplane width: " + opstatS1.getAirplaneWidth() + "m");
				System.out.println("          Navigation Accuracy Category for velocity (NACv): " + opstatS1.getNACv());
				System.out.println("          Low (<70W) TX power: " + opstatS1.hasLowTxPower());
				System.out.println("          Encoded GPS antenna offset: " + opstatS1.getGPSAntennaOffset());
				System.out.println("          Has track heading info: " + opstatS1.hasTrackHeadingInfo());

				// SIL supplement in version 2
				if (msg instanceof SurfaceOperationalStatusV2Msg) {
					System.out.println("          Has SIL supplement: " + ((SurfaceOperationalStatusV2Msg) msg).hasSILSupplement());
				}

				break;
			case ADSB_TCAS:
				TCASResolutionAdvisoryMsg tcas = (TCASResolutionAdvisoryMsg) msg;
				System.out.println("["+icao24+"]: TCAS Resolution Advisory completed: "+tcas.hasRATerminated());
				System.out.println("          Threat type is "+tcas.getThreatType());
				if (tcas.getThreatType() == 1) // it's a icao24 address
					System.out.println("          Threat identity is 0x"+String.format("%06x", tcas.getThreatIdentity()));
				break;
			case ADSB_VELOCITY:
				VelocityOverGroundMsg veloc = (VelocityOverGroundMsg) msg;
				System.out.println("["+icao24+"]: Velocity: "+(veloc.hasVelocityInfo() ? veloc.getVelocity() : "unknown")+" kt");
				System.out.println("          Heading: "+(veloc.hasVelocityInfo() ? veloc.getHeading() : "unknown")+" °");
				System.out.println("          Vertical rate: "+(veloc.hasVerticalRateInfo() ? veloc.getVerticalRate() : "unknown")+" ft/min");

				// the IFR flag is only used in ADS-B version 1. Although equipage is low, we still support it
				if (decoder.getAdsbVersion(veloc) == 1)
					System.out.println("          Has IFR capability: " + veloc.hasIFRCapability());

				break;
			case ADSB_TARGET_STATE_AND_STATUS:
				TargetStateAndStatusMsg tStatus = (TargetStateAndStatusMsg) msg;
				System.out.println("["+icao24+"]: Target State and Status reported");
				System.out.println("          Navigation Accuracy Category for position (NACp): " + tStatus.getNACp());
				System.out.println("          Has operational TCAS: " + tStatus.hasOperationalTCAS());
				System.out.println("          Surveillance/Source Integrity Level (SIL): " + tStatus.getSIL());
				System.out.println("          Has SIL supplement: " + tStatus.hasSILSupplement());
				System.out.println("          Barometric altitude cross-checked: " + tStatus.getBarometricAltitudeIntegrityCode());

				System.out.printf("          Selected altitude is derived from %s\n", tStatus.isFMSSelectedAltitude() ? "FMS" : "MCP/FCU");
				if (tStatus.hasSelectedAltitudeInfo()) {
					System.out.println("          Selected altitude: " + tStatus.getSelectedAltitude() + " ft");
				} else {
					System.out.println("          No selected altitude info");
				}

				if (tStatus.hasBarometricPressureSettingInfo()) {
					System.out.println("          Barometric pressure setting (minus 800 mbar): " + tStatus.getBarometricPressureSetting() + " mbar");
				} else {
					System.out.println("          No barometric pressure setting info");
				}

				if (tStatus.hasSelectedHeadingInfo()) {
					System.out.println("          Selected heading: " + tStatus.getSelectedHeading() + "°");
				} else {
					System.out.println("          No selected heading info");
				}
				if (tStatus.hasModeInfo()) {
					System.out.printf("          Autopilot is%s enganged\n", tStatus.hasAutopilotEngaged() ? "" : " not");
					System.out.printf("          VNAV mode is%s enganged\n", tStatus.hasVNAVModeEngaged() ? "" : " not");
					System.out.printf("          Altitude hold mode is%s enganged\n", tStatus.hasActiveAltitudeHoldMode() ?	"" : " not");
					System.out.printf("          Approach mode is%s enganged\n", tStatus.hasActiveApproachMode() ? "" : " not");
					System.out.printf("          LNAV mode is%s enganged\n", tStatus.hasLNAVModeEngaged() ? "" : " not");
				} else {
					System.out.println("          No MCP/FCU mode info");
				}

				break;
			case EXTENDED_SQUITTER:
				System.out.println("["+icao24+"]: Unknown extended squitter with type code "+((ExtendedSquitter)msg).getFormatTypeCode()+"!");
				break;
			}
		}
		else if (msg.getDownlinkFormat() != 17) { // CRC failed
			switch (msg.getType()) {
			case MODES_REPLY:
				System.out.println("["+icao24+"]: Unknown message with DF "+msg.getDownlinkFormat());
				break;
			case SHORT_ACAS:
				ShortACAS acas = (ShortACAS)msg;
				System.out.println("["+icao24+"]: Altitude is "+acas.getAltitude()+"ft and ACAS is "+
						(acas.hasOperatingACAS() ? "operating." : "not operating."));
				System.out.println("          A/C is "+(acas.isAirborne() ? "airborne" : "on the ground")+
						" and sensitivity level is "+acas.getSensitivityLevel());
				break;
			case ALTITUDE_REPLY:
				AltitudeReply alti = (AltitudeReply)msg;
				System.out.println("["+icao24+"]: Short altitude reply: "+alti.getAltitude()+"ft");
				break;
			case IDENTIFY_REPLY:
				IdentifyReply identify = (IdentifyReply)msg;
				System.out.println("["+icao24+"]: Short identify reply: "+identify.getIdentity());
				break;
			case ALL_CALL_REPLY:
				AllCallReply allcall = (AllCallReply)msg;
				System.out.println("["+icao24+"]: All-call reply for "+tools.toHexString(allcall.getInterrogatorCode())+
						" ("+(allcall.hasValidInterrogatorCode()?"valid":"invalid")+")");
				break;
			case LONG_ACAS:
				LongACAS long_acas = (LongACAS)msg;
				System.out.println("["+icao24+"]: Altitude is "+long_acas.getAltitude()+"ft and ACAS is "+
						(long_acas.hasOperatingACAS() ? "operating." : "not operating."));
				System.out.println("          A/C is "+(long_acas.isAirborne() ? "airborne" : "on the ground")+
						" and sensitivity level is "+long_acas.getSensitivityLevel());
				System.out.println("          RAC is "+(long_acas.hasValidRAC() ? "valid" : "not valid")+
						" and is "+long_acas.getResolutionAdvisoryComplement()+" (MTE="+long_acas.hasMultipleThreats()+")");
				System.out.println("          Maximum airspeed is "+long_acas.getMaximumAirspeed()+"kn.");
				break;
			case MILITARY_EXTENDED_SQUITTER:
				MilitaryExtendedSquitter mil = (MilitaryExtendedSquitter)msg;
				System.out.println("["+icao24+"]: Military ES of application "+mil.getApplicationCode());
				System.out.println("          Message is 0x"+tools.toHexString(mil.getMessage()));
				break;
			case COMM_B_ALTITUDE_REPLY:
				CommBAltitudeReply commBaltitude = (CommBAltitudeReply)msg;
				System.out.println("["+icao24+"]: Long altitude reply: "+commBaltitude.getAltitude()+"ft");
				break;
			case COMM_B_IDENTIFY_REPLY:
				CommBIdentifyReply commBidentify = (CommBIdentifyReply)msg;
				System.out.println("["+icao24+"]: Long identify reply: "+commBidentify.getIdentity());
				break;
			case COMM_D_ELM:
				CommDExtendedLengthMsg commDELM = (CommDExtendedLengthMsg)msg;
				System.out.println("["+icao24+"]: ELM message w/ sequence no "+commDELM.getSequenceNumber()+
						" (ACK: "+commDELM.isAck()+")");
				System.out.println("          Message is 0x"+tools.toHexString(commDELM.getMessage()));
				break;
			default:
			}
		}
		else {
			System.out.println("Message contains biterrors.");
		}
	}

	public static void main(String[] args) throws Exception {
		// iterate over STDIN
		Scanner sc = new Scanner(System.in, "UTF-8");
		ExampleDecoder dec = new ExampleDecoder();
		Position rec = new Position(0., 0., 0.);
		while(sc.hasNext()) {
		  String[] values = sc.nextLine().split(",");

		  if (values.length == 5) {
			  // time,serial,lat,lon,msg
			  rec.setLatitude(Double.parseDouble(values[2]));
			  rec.setLongitude(Double.parseDouble(values[3]));
			  dec.decodeMsg((long) Double.parseDouble(values[0])*1000, values[4], rec);
		  } else if (values.length == 4) {
			  // time,lat,lon,msg
			  rec.setLatitude(Double.parseDouble(values[1]));
			  rec.setLongitude(Double.parseDouble(values[2]));
			  dec.decodeMsg((long) Double.parseDouble(values[0])*1000, values[3], rec);
		  } else if (values.length == 2) {
			  // time,msg
			  dec.decodeMsg((long) Double.parseDouble(values[0])*1000, values[1], null);
		  }
		}
		sc.close();
	}
}