<param xml:id="vo2_b_urartn_phi">
    <get>
      <amdaParam name="vo2_b_urartn" />
    </get>
    <process>180+RAD2DEG*atan2(-$vo2_b_urartn[1],-$vo2_b_urartn[0])</process>
    <output />
  </param>