diff --git a/libraries/AP_GPS/AP_GPS_SIRF.cpp b/libraries/AP_GPS/AP_GPS_SIRF.cpp
index 9daceafb4a..97e686e9e6 100644
--- a/libraries/AP_GPS/AP_GPS_SIRF.cpp
+++ b/libraries/AP_GPS/AP_GPS_SIRF.cpp
@@ -170,7 +170,9 @@ AP_GPS_SIRF::_parse_gps(void)
 		longitude		= _swapl(&_buffer.nav.longitude);
 		altitude		= _swapl(&_buffer.nav.altitude_msl);
 		ground_speed	= _swapi(&_buffer.nav.ground_speed);
-		ground_course	= _swapi(&_buffer.nav.ground_course);
+		// at low speeds, ground course wanders wildly; suppress changes if we are not moving
+		if (ground_speed > 50)
+			ground_course	= _swapi(&_buffer.nav.ground_course);
 		num_sats		= _buffer.nav.satellites;
 		break;
 	}
diff --git a/libraries/AP_GPS/examples/GPS_406_test/GPS_406_test.pde b/libraries/AP_GPS/examples/GPS_406_test/GPS_406_test.pde
index 72ecab4df6..8ffadd5680 100644
--- a/libraries/AP_GPS/examples/GPS_406_test/GPS_406_test.pde
+++ b/libraries/AP_GPS/examples/GPS_406_test/GPS_406_test.pde
@@ -18,8 +18,10 @@ AP_GPS_406 gps(&Serial1);
 
 void setup()
 {
-	Serial.begin(38400);
-	Serial1.begin(57600);
+	tone(A6, 1000, 200);
+
+	Serial.begin(38400, 16, 128);
+	Serial1.begin(57600, 128, 16);
 	stderr = stdout;
 	gps.print_errors = true;