added gnss and time reference messages

CMakeLists.txt

@@ -10,6 +10,10 @@ add_message_files(
   axis_state.msg
   proximity.msg
   analog_voltage.msg
+  time_reference.msg
+  gnss_fix.msg
+  gnss_position.msg
+  gnss_track.msg
 )
 
 # Add service files.

msg/gnss_fix.msg

@@ -0,0 +1,19 @@
+# Describes the status of a GNSS receiver's fix.
+
+uint8 type                            # The current fix type.
+uint8 TYPE_NO_FIX = 0
+uint8 TYPE_FIX = 1
+uint8 TYPE_DIFFERENTIAL = 2
+uint8 TYPE_RTK_FIXED = 4
+uint8 TYPE_RTK_FLOAT = 5
+
+uint8 mode_selection                  # The selection type for the operating mode.
+uint8 MODE_SELECTION_MANUAL
+uint8 MODE_SELECTiON_AUTOMATIC
+
+uint8 mode                            # The current operating mode.
+uint8 MODE_NONE = 0
+uint8 MODE_2D = 1
+uint8 MODE_3D = 2
+
+uint8 n_satellites                     # The number of satellites used in the fix solution.

msg/gnss_position.msg

@@ -0,0 +1,12 @@
+# A global position measurement from a GNSS sensor.
+
+string frame_id             # The ID of the GNSS coordinate frame.
+
+bool fix_3d                 # Indicates if the fix is 3-dimensional (includes altitude).
+
+float64 latitude            # Degrees latitude (positive = N, negative = S).
+float64 longitude           # Degrees longitude (positive = E, negative = W).
+float64 altitude            # Altitude above MSL (in meters).
+
+bool has_covariance         # Indicates if a covariance matrix is provided in this measurement.
+float64[9] covariance       # The covariance matrix of the measurement for lat,lon,alt.

msg/gnss_track.msg

@@ -0,0 +1,9 @@
+# An instantaneous velocity track as measured by a GNSS receiver.
+
+uint8 reference                       # The direction that the heading is in reference to.
+uint8 REFERENCE_TRUE_NORTH = 0
+uint8 REFERENCE_MAGNETIC_NORTH = 1
+
+float64 heading                         # The global heading of the track, in degrees from reference north.
+                                        # This can be in reference to TRUE or MAGNETIC north.
+float64 velocity                        # The scalar velocity of the track, in m/s.

msg/time_reference.msg

@@ -0,0 +1,4 @@
+# A time measurement from a timing source.
+
+string source       # The timing source generating the measurement.
+time utc_time       # The measured UTC time.