All disconnect/reconnect of RTK GPS

src/GPS/GPSManager.h

@@ -29,7 +29,7 @@ public:
     ~GPSManager();
 
     void connectGPS(const QString& device);
-    bool connected(void) const { return _gpsProvider != nullptr; }
+    bool connected(void) const { return _gpsProvider && _gpsProvider->isRunning(); }
 
 private slots:
     void GPSPositionUpdate(GPSPositionMessage msg);