Update osi_object.proto

Author: ThomasNaderBMW

osi_object.proto

@@ -443,7 +443,7 @@ message MovingObject
         //
         repeated WheelData wheel_data = 7;
 
-        // \brief Information for a single wheel.
+        // \brief Description of a single wheel.
         //
         message WheelData
         {
@@ -461,14 +461,17 @@ message MovingObject
             //
             optional uint32 index = 2;
 
-            // The coordinates are given globally.
-            // Reference point is the center of the wheel.
+            // Position of the wheel (geographical center of the wheel).
+            // The reference system is the vehicle frame (center of bounding box).
+            // Right-handed, x-axis shows into driving direction "forward".
+            // Rough Approximation: The z-value shows the damping.
             //
             optional Vector3d position = 3;
 
-            // The orientation is given globally.
-            // E.g. a calculation of the steering angle can then be done by:
-            // moving_object.yaw - wheel.yaw
+            // Orientation of the wheel.
+            // The reference system is the vehicle frame (center of bounding box).
+            // Right-handed, x-axis shows into driving direction "forward".
+            // Rough Approximation: The yaw-value shows the steering angle.
             //
             optional Orientation3d orientation = 4;