Allow BDS 50 roll angle up to 50 degrees

Other libraries use a similar value. This reduces number of undecodable message, but it will increase false positives in multi matches.

src/main/java/aero/t2s/modes/decoder/df/bds/Bds50.java

@@ -152,7 +152,7 @@ public Bds50(short[] data) {
  return;
  }
  if (statusRollAngle) {
- if (Math.abs(rollAngle) > 32) {
+ if (Math.abs(rollAngle) > 50) {
  invalidate();
  rollAngle = 0;
  return;

src/test/java/aero/t2s/modes/decoder/df/DfRealMessageTest.java

@@ -166,6 +166,32 @@ public void test_df21_bds60_406ECD() throws UnknownDownlinkFormatException {
  assertEquals(104.7, bds.getMagneticHeading(), 0.1);
  }
 
+
+ @Test
+ public void test_df21_bds50_406ECD() throws UnknownDownlinkFormatException {
+ DownlinkFormat df = testMessage("A0000333E17987192250004423EC");
+
+ assertInstanceOf(DF20.class, df);
+ DF20 df20 = (DF20) df;
+ assertEquals("44CD73", df.getIcao()); // Military / corrupt transponder
+ assertEquals(4275, df20.getAltitude().getAltitude());
+
+ assertTrue(df20.isValid());
+ assertInstanceOf(Bds50.class, df20.getBds());
+
+ Bds50 bds = (Bds50) df20.getBds();
+ assertTrue(bds.isStatusGs());
+ assertEquals(200, bds.getGs(), 0.1);
+ assertFalse(bds.isStatusTas());
+ assertEquals(0, bds.getTas(), 0.1);
+ assertTrue(bds.isStatusRollAngle());
+ assertEquals(-43, bds.getRollAngle(), 0.1);
+ assertTrue(bds.isStatusTrueAngleRate());
+ assertEquals(2.3, bds.getTrackAngleRate(), 0.1);
+ assertTrue(bds.isStatusTrackAngle());
+ assertEquals(214.2, bds.getTrueTrack(), 0.1);
+ }
+
  private DownlinkFormat testMessage(String message) throws UnknownDownlinkFormatException {
  Decoder decoder = new Decoder(new HashMap<>(), 50, 2, ModeSDatabase.createDatabase());