multi: removed frame_ids and improved documentation

msg/axis_state.msg

@@ -1,7 +1,5 @@
 # Reports the instantaneous state of an axis.
 
-float64 position            # The current position of the axis in radians.
-float64 velocity            # The current velocity of the axis in radians/second.
-float64 acceleration        # The current acceleration of the axis in radians/second^2.
-
-string frame_id             # The id of the measurement's frame.
+float64 position            # The current position of the axis [rad]
+float64 velocity            # The current velocity of the axis [rad/s]
+float64 acceleration        # The current acceleration of the axis [rad/s^2]

msg/gnss_position.msg

@@ -1,12 +1,10 @@
 # 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).
+float64 altitude            # Altitude above MSL [m]
 
 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

@@ -4,6 +4,5 @@ uint8 reference                       # The direction that the heading is in ref
 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.
+float64 heading                         # The global heading of the track w.r.t. the reference [rad].
+float64 velocity                        # The scalar velocity of the track, [m/s]

msg/time_reference.msg

@@ -1,4 +1,3 @@
 # A time measurement from a timing source.
 
-string source       # The timing source generating the measurement.
 time utc_time       # The measured UTC time.