def get_ipts_13
      recl = 4

      begin
        ipts = (0..2).map do |i|
          File.binread(@bin_path, recl, @pos + recl * i).unpack("I*")[0]
        end
        @pos += recl * 3
        return ipts
      rescue => e
        raise
      end
    end
def get_ipts_13
      recl = 4

      begin
        ipts = (0..2).map do |i|
          File.binread(@bin_path, recl, @pos + recl * i).unpack("I*")[0]
        end
        @pos += recl * 3
        return ipts
      rescue => e
        raise
      end
    end
=========================================================================
 IPT_13(Month's libration)

 @param:  <none>
 @return: Array of IPT
=========================================================================