RemoteID/PositionManager: fix GCS Live GNSS position

src/PositionManager/PositionManager.cpp

@@ -119,11 +119,18 @@ void QGCPositionManager::_positionUpdated(const QGeoPositionInfo &update)
         }
     }
 
+    // Accept the altitude when the fix carries one and the vertical accuracy is either
+    // acceptable or not reported at all. The Android position source typically reports a
+    // vertical accuracy well above the old 10m gate (or none), which used to drop the
+    // altitude entirely and leave consumers such as Remote ID (which mandates an operator
+    // altitude in FAA regions) with a NaN.
+    bool verticalAccuracyOk = true;
     if (update.hasAttribute(QGeoPositionInfo::VerticalAccuracy)) {
         _gcsPositionVerticalAccuracy = update.attribute(QGeoPositionInfo::VerticalAccuracy);
-        if (_gcsPositionVerticalAccuracy <= kMinVerticalAccuracyMeters) {
-            newGCSPosition.setAltitude(update.coordinate().altitude());
-        }
+        verticalAccuracyOk = (_gcsPositionVerticalAccuracy <= kMinVerticalAccuracyMeters);
+    }
+    if ((update.coordinate().type() == QGeoCoordinate::Coordinate3D) && verticalAccuracyOk) {
+        newGCSPosition.setAltitude(update.coordinate().altitude());
     }
 
     _gcsPositionAccuracy = sqrt(pow(_gcsPositionHorizontalAccuracy, 2) + pow(_gcsPositionVerticalAccuracy, 2));

src/PositionManager/PositionManager.h

@@ -85,6 +85,6 @@ private slots:
     QGCCompass *_compass = nullptr;
 
     static constexpr qreal kMinHorizonalAccuracyMeters = 100.;
-    static constexpr qreal kMinVerticalAccuracyMeters = 10.;
+    static constexpr qreal kMinVerticalAccuracyMeters = 100.;
     static constexpr qreal kMinDirectionAccuracyDegrees = 30.;
 };

src/Vehicle/RemoteIDManager.cc

@@ -488,6 +488,10 @@ void RemoteIDManager::setEmergency(bool declare)
 void RemoteIDManager::_updateLastGCSPositionInfo(QGeoPositionInfo update)
 {
     if (update.isValid()) {
-        _lastGeoPositionTimeStamp = update.timestamp().toUTC();
+        // Stamp the local arrival time rather than update.timestamp(). The freshness
+        // check in _sendSystem() compares this against the local wall clock, and on some
+        // platforms (e.g. Android) the position source's own timestamp is offset from the
+        // system clock, which made gcsGPSGood flap green/red even with a healthy fix.
+        _lastGeoPositionTimeStamp = QDateTime::currentDateTimeUtc();
     }
 }