Merge pull request #50 from terminal2/EvenOddPositions

Move from local position decoding to global unambiguous position decoding when possible

gradle.properties

@@ -1,5 +1,5 @@
 GROUP=aero.t2s
-VERSION_NAME=0.2.5-SNAPSHOT
+VERSION_NAME=0.2.6-SNAPSHOT
 
 POM_ARTIFACT_ID=mode-s
 POM_NAME=Mode-S/ADS-B (1090Mhz)

src/main/java/aero/t2s/modes/CprPosition.java

@@ -1,9 +1,28 @@
 package aero.t2s.modes;
 
+import java.time.Instant;
+
 public class CprPosition {
  private double lat;
  private double lon;
- private int time;
+ private boolean valid;
+ private long time;
+
+ public CprPosition() {
+ this.lat = 0.0;
+ this.lon = 0.0;
+ this.valid = false;
+ }
+ public CprPosition(double lat, double lon) {
+ setLatLon(lat ,lon);
+ }
+
+ public void setLatLon(double lat, double lon) {
+ this.lat = lat;
+ this.lon = lon;
+ this.time = Instant.now().toEpochMilli();
+ this.valid = true;
+ }
 
  public void setLat(double lat) {
  this.lat = lat;
@@ -21,15 +40,19 @@ public double getLon() {
  return lon;
  }
 
- public void setTime(int time) {
+ public void setTime(long time) {
  this.time = time;
  }
 
- public int getTime() {
+ public long getTime() {
  return time;
  }
 
  public boolean isValid() {
- return lat != 0d && lon != 0;
+ return valid;
+ }
+
+ public boolean isExpired() {
+ return time < Instant.now().minusSeconds(10).toEpochMilli();
  }
 }

src/main/java/aero/t2s/modes/ModeSHandler.java

@@ -1,6 +1,7 @@
 package aero.t2s.modes;
 
 import aero.t2s.modes.decoder.df.DownlinkFormat;
+import aero.t2s.modes.decoder.df.df17.AirbornePosition;
 
 import java.util.function.Consumer;
 
@@ -42,10 +43,10 @@ protected short[] toData(final String input) throws EmptyMessageException, ModeA
  }
 
  public void start() {
-
+ AirbornePosition.start();
  }
 
  public void stop() {
-
+ AirbornePosition.stop();
  }
 }

src/main/java/aero/t2s/modes/Track.java

@@ -11,6 +11,7 @@ public class Track {
  private Altitude altitude = new Altitude();
  private double lat;
  private double lon;
+ private boolean positionAvailable = false;
  private int vx;
  private int vy;
  private double gs;
@@ -172,7 +173,13 @@ public boolean isGroundBit() {
  return groundBit;
  }
 
+ public void setLatLon(double lat, double lon) {
+ this.lat = lat;
+ this.lon = lon;
+ this.positionAvailable = true;
+ }
  public void setLat(double lat) {
+ //TODO How do we know if position really is available if we only set the lat? Can we remove this method?
  this.lat = lat;
  }
 
@@ -181,6 +188,7 @@ public double getLat() {
  }
 
  public void setLon(double lon) {
+ //TODO How do we know if position really is available if we only set the lon? Can we remove this method?
  this.lon = lon;
  }
 
@@ -245,7 +253,7 @@ public int getModeA() {
  }
 
  public boolean isPositionAvailable() {
- return lat != 0 & lon != 0;
+ return positionAvailable;
  }
 
  public void setGeometricHeightOffset(int geometricHeightOffset) {

src/main/java/aero/t2s/modes/decoder/Decoder.java

@@ -50,7 +50,7 @@ public DownlinkFormat decode(short[] data) throws UnknownDownlinkFormatException
  df = new DF16(data);
  break;
  case 17:
- df = new DF17(data, originLat, originLon);
+ df = new DF17(data);
  break;
  case 18:
  df = new DF18(data);

src/main/java/aero/t2s/modes/decoder/df/DF17.java

@@ -4,15 +4,10 @@
 import aero.t2s.modes.decoder.df.df17.*;
 
 public class DF17 extends DownlinkFormat {
- private final double originLat;
- private final double originLon;
-
  private ExtendedSquitter extendedSquitter;
 
- public DF17(short[] data, double originLat, double originLon) {
+ public DF17(short[] data) {
  super(data, IcaoAddress.FROM_MESSAGE);
- this.originLat = originLat;
- this.originLon = originLon;
  }
 
  @Override
@@ -34,7 +29,7 @@ public DF17 decode() {
  case 20:
  case 21:
  case 22:
- extendedSquitter = new AirbornePosition(data, originLat, originLon);
+ extendedSquitter = new AirbornePosition(data, getIcao());
  break;
  case 1:
  case 2: