Index: /trunk/src/org/openstreetmap/josm/io/rtklib/RtkLibPosReader.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/io/rtklib/RtkLibPosReader.java	(revision 15249)
+++ /trunk/src/org/openstreetmap/josm/io/rtklib/RtkLibPosReader.java	(revision 15250)
@@ -22,4 +22,5 @@
 import org.openstreetmap.josm.io.IGpxReader;
 import org.openstreetmap.josm.tools.Logging;
+import org.openstreetmap.josm.tools.date.DateUtils;
 import org.xml.sax.SAXException;
 
@@ -61,4 +62,5 @@
     public RtkLibPosReader(InputStream source) throws IOException {
         this.source = Objects.requireNonNull(source);
+        dateTimeFmt.setTimeZone(DateUtils.UTC);
     }
 
Index: /trunk/src/org/openstreetmap/josm/tools/date/DateUtils.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/tools/date/DateUtils.java	(revision 15249)
+++ /trunk/src/org/openstreetmap/josm/tools/date/DateUtils.java	(revision 15250)
@@ -36,5 +36,5 @@
      * The UTC time zone.
      */
-    public static final TimeZone UTC = TimeZone.getTimeZone("UTC");
+    public static final TimeZone UTC = TimeZone.getTimeZone(ZoneOffset.UTC);
 
     /**
Index: /trunk/test/unit/org/openstreetmap/josm/io/rtklib/RtkLibPosReaderTest.java
===================================================================
--- /trunk/test/unit/org/openstreetmap/josm/io/rtklib/RtkLibPosReaderTest.java	(revision 15249)
+++ /trunk/test/unit/org/openstreetmap/josm/io/rtklib/RtkLibPosReaderTest.java	(revision 15250)
@@ -55,12 +55,12 @@
 
         List<WayPoint> wayPoints = new ArrayList<>(in.getGpxData().tracks.iterator().next().getSegments().iterator().next().getWayPoints());
-        assertEquals(DateUtils.fromString("2019-06-08T06:23:12.000Z"), wayPoints.get(0).get(GpxConstants.PT_TIME));
-        assertEquals(DateUtils.fromString("2019-06-08T06:23:12.300Z"), wayPoints.get(1).get(GpxConstants.PT_TIME));
-        assertEquals(DateUtils.fromString("2019-06-08T06:23:12.600Z"), wayPoints.get(2).get(GpxConstants.PT_TIME));
+        assertEquals(DateUtils.fromString("2019-06-08T08:23:12.000Z"), wayPoints.get(0).get(GpxConstants.PT_TIME));
+        assertEquals(DateUtils.fromString("2019-06-08T08:23:12.300Z"), wayPoints.get(1).get(GpxConstants.PT_TIME));
+        assertEquals(DateUtils.fromString("2019-06-08T08:23:12.600Z"), wayPoints.get(2).get(GpxConstants.PT_TIME));
         assertEquals(wayPoints.get(0).getDate(), wayPoints.get(0).get(GpxConstants.PT_TIME));
 
-        assertEquals("2019-06-08T06:23:12.000Z", iso8601.format(wayPoints.get(0).getDate()));
-        assertEquals("2019-06-08T06:23:12.300Z", iso8601.format(wayPoints.get(1).getDate()));
-        assertEquals("2019-06-08T06:23:12.600Z", iso8601.format(wayPoints.get(2).getDate()));
+        assertEquals("2019-06-08T08:23:12.000Z", iso8601.format(wayPoints.get(0).getDate()));
+        assertEquals("2019-06-08T08:23:12.300Z", iso8601.format(wayPoints.get(1).getDate()));
+        assertEquals("2019-06-08T08:23:12.600Z", iso8601.format(wayPoints.get(2).getDate()));
 
         assertEquals(new LatLon(46.948881673, -1.484757046), wayPoints.get(0).getCoor());