Updated Bounding Box Documentation.

@@ -51,31 +51,33 @@
     <struct name="BoundingBox" pack="true">
 
       <comment>Defines a bounding box in WGS84 reference frame.</comment>
-      <comment>Units for latitude and longitude are in units of micro degrees (1e-6 degrees) providing for about 11 cm resolution near the equator.</comment>
+      <comment>
+          Units for latitude and longitude are in units of micro degrees (1e-6 degrees) providing for about 11 cm resolution near the equator. Altitude units are in millimeters.
+      </comment>
       <elem name="latmin" type="Tensor.int32" multiplicity="1" >
-        <comment>Minimum value of the latitude.</comment>
+        <comment>Minimum value of the latitude. Valid range is -90,000,000 <= lat <= 90,000,000. </comment>
         <tag name="unit" value="microdegrees"/>
       </elem>
       <elem name="latmax" type="Tensor.int32" multiplicity="1" >
-        <comment>Maximum value of the latitude.</comment>
+        <comment>Maximum value of the latitude. Valid range is -90,000,000 <= lat <= 90,000,000.</comment>
         <tag name="unit" value="microdegrees"/>
       </elem>
       <elem name="lonmin" type="Tensor.int32" multiplicity="1" >
-        <comment>Minimum value of the longitude.</comment>
+        <comment>Minimum value of the longitude. Valid range is -180,000,000 <= lat <= 180,000,000.</comment>
         <tag name="unit" value="microdegrees"/>
       </elem>
       <elem name="lonmax" type="Tensor.int32" multiplicity="1" >
-        <comment>Maximum value of the longitude.</comment>
+        <comment>Maximum value of the longitude. Valid range is -180,000,000 <= lat <= 180,000,000.</comment>
         <tag name="unit" value="microdegrees"/>
       </elem>
 
       <elem name="altmin" type="Tensor.int32" multiplicity="1" >
-        <comment>Minimum value of the altitude.</comment>
-        <tag name="unit" value="microdegrees"/>
+        <comment>Minimum value of the altitude.  Valid range is +- 1,000,000,000 cm.</comment>
+        <tag name="unit" value="cm"/>
       </elem>
       <elem name="altmax" type="Tensor.int32" multiplicity="1" >
-        <comment>Maximum value of the altitude.</comment>
-        <tag name="unit" value="microdegrees"/>
+        <comment>Maximum value of the altitude. Valid range is +- 1,000,000,000 cm.</comment>
+        <tag name="unit" value="cm"/>
       </elem>
 
     </struct>