obstacle_distance: update distances description according to latest...

obstacle_distance: update distances description according to latest obstacle_distance mavlink message

msg/obstacle_distance.msg

@@ -7,7 +7,7 @@ uint8 MAV_DISTANCE_SENSOR_ULTRASOUND = 1
 uint8 MAV_DISTANCE_SENSOR_INFRARED = 2
 uint8 MAV_DISTANCE_SENSOR_RADAR = 3
 
-uint16[72] distances # Distance of obstacles in front of the sensor starting on the left side. A value of 0 means that the obstacle is right in front of the sensor. A value of max_distance +1 means no obstace is present. A value of UINT16_MAX for unknown/not used. In a array element, each unit corresponds to 1cm.
+uint16[72] distances # Distance of obstacles around the UAV with index 0 corresponding to local North. A value of 0 means that the obstacle is right in front of the sensor. A value of max_distance +1 means no obstacle is present. A value of UINT16_MAX for unknown/not used. In a array element, one unit corresponds to 1cm.
 
 uint8 increment # Angular width in degrees of each array element.