Added uncertainty to the sparse tile RfData structure using the reserved field.

@@ -132,10 +132,10 @@
           <comment>index of the Position element.</comment>
         </elem>
         <elem name="value" type="Tensor.byte" multiplicity="1">
-          <comment>The RF signal strengh value in scaled units where unscaled scaled value = (value + dataOffset)/dataScale.</comment>
+          <comment>The RF signal strengh value in scaled units where  the value = (Vunscaled*dataScale - offset), or Vunscaled = (value + offset)/dataScale.</comment>
         </elem>
-        <elem name="reserved" type="Tensor.byte" multiplicity="1">
-          <comment>Reserved storage space.</comment>
+        <elem name="uncertainty" type="Tensor.byte" multiplicity="1">
+          <comment>Uncertainty of the RF measured value in scaled units such that  uncertainty = Uunscaled*dataScale, or Uunscaled= uncertainty/dataScale.</comment>
         </elem>
       </struct>