Improve BDS40 detection by allowing empty FMS altitude if status is a…

…vailable
terminal2 · Oct 12, 2022 · 83bd0c2 · 83bd0c2
1 parent c6daacd
commit 83bd0c2
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Showing 2 changed files with 28 additions and 1 deletion.
diff --git a/src/main/java/aero/t2s/modes/decoder/df/bds/Bds40.java b/src/main/java/aero/t2s/modes/decoder/df/bds/Bds40.java
@@ -126,7 +126,7 @@ public Bds40(short[] data) {
 
  fmsAltitude = (((data[5] & 0x3) << 10) | (data[6] << 2) | ((data[7] >>> 6) & 0x3)) * 16;
  if (statusFms) {
- if (fmsAltitude <= 0 || fmsAltitude > 52000) {
+ if (fmsAltitude < 0 || fmsAltitude > 52000) {
  invalidate();
  return;
  }

diff --git a/src/test/java/aero/t2s/modes/decoder/df/DfRealMessageTest.java b/src/test/java/aero/t2s/modes/decoder/df/DfRealMessageTest.java
@@ -192,6 +192,33 @@ public void test_df21_bds50_44CD73() throws UnknownDownlinkFormatException {
  assertEquals(214.2, bds.getTrueTrack(), 0.1);
  }
 
+ @Test
+ public void test_df21_bds40_407776() throws UnknownDownlinkFormatException {
+ DownlinkFormat df = testMessage("A000169EB2CC0030A80106C25083");
+
+ assertInstanceOf(DF20.class, df);
+ DF20 df20 = (DF20) df;
+ assertEquals("407776", df.getIcao()); // Military / corrupt transponder
+ assertEquals(35350, df20.getAltitude().getAltitude());
+
+ assertTrue(df20.isValid());
+ assertInstanceOf(Bds40.class, df20.getBds());
+
+ Bds40 bds = (Bds40) df20.getBds();
+ assertTrue(bds.isStatusMcp());
+ assertEquals(26000, bds.getSelectedAltitude(), 0.1);
+ assertTrue(bds.isStatusFms());
+ assertEquals(0, bds.getFmsAltitude(), 0.1);
+ assertTrue(bds.isStatusBaro());
+ assertEquals(1013.2, bds.getBaro(), 0.1);
+ assertTrue(bds.isStatusTargetSource());
+ assertEquals(SelectedAltitudeSource.MCP, bds.getSelectedAltitudeSource());
+ assertTrue(bds.isStatusMcpMode());
+ assertFalse(bds.isAutopilotVnav());
+ assertFalse(bds.isAutopilotAltitudeHold());
+ assertFalse(bds.isAutopilotApproach());
+ }
+
  private DownlinkFormat testMessage(String message) throws UnknownDownlinkFormatException {
  Decoder decoder = new Decoder(new HashMap<>(), 50, 2, ModeSDatabase.createDatabase());