Figur 7-21.  V OR/DME Figure 9-24. VOR/DME RNAV RWY 25 approach (excerpt). Figure 9-25. Aircraft/DME/waypoint relationship. VOR/DME RNAV Errors Advanced Technologies Global Navigation Satellite System (GNSS) RNAV equipment  computes the rate of  descent relative to  the groundspeed; on some installations, it  displays vertical  guidance  information on the GS indicator.  When using this  type of equipment  during an instrument  approach, the  pilot must keep in mind that the vertical guidance information provided is not part  of the nonprecision  approach. Published  nonprecision appr oach altitudes must be o bserved  and  complied with, unless otherwise directed by ATC. To fly to a WP using  RNAV, observe the followi ng proce d ure  [Figure 9-25] : The limitation of this system is the reception volume.  Published approaches have been tested to ensure this is not  a problem. Descents/approaches to airports distant from the  VOR/DME facility may not be possible because, during  the approach, the aircraft may descend below the reception  altitude of the facility at that distance. The Global Navigation Satellite System (GNSS) is a  constellation of satellites providing a high-frequency signal  that contains time and distance that is picked up by a receiver  1.  Select the VOR/DME frequency. 2.  Select the  RNAV mode. 3.  Select the radial of the VOR that passes through the  WP (225°). 4.  Select the distance from the DME to the WP (12 NM). 5.  Check and confirm all inputs, and center the CDI needle  with the TO indicator showing. 6.  Maneuver the aircraft to fly the indicated heading plus or  minus wind correction to keep the CDI needle centered. 7.  The CDI needle indicates distance off course of 1 NM  per dot; the DME readout indicates distance in NM  from the WP; the groundspeed reads closing speed  (knots) to the WP; and the time to station (TTS) reads  time to the WP. 9-24 OBS  N  E S  W  3  33  24  21  15  12  30  6  TO  Waypoint  135 °  225 °  OBS $^{N }$ E  S  W  3  33  24  21  15  12  30  6  TO 33  30  24  2I  I5  I2  6  3  1 2 $_{ }$N M OBS N E S W 3 33 24 21 15 12 30 6 NAV GS Instrument view is  from the pilot’s  perspective, and  the movable card is  reset after each turn E C - 1 ,  E C - 1 ,   1 6  DEC2010to13JAN2011  16DEC2010to13JAN  2 011