The Global Positioning System (GPS) is a satellite-based navigation system made up of a network of 24 satellites placed into orbit by the U.S. Department of Defense. GPS was originally intended for military applications, but in the 1980s, the government made the system available for civilian use.

The signals travel by line of sight, meaning they will pass through clouds, glass and plastic but will not go through most solid objects such as buildings and mountains. GPS satellites circle the earth twice a day in a very precise orbit and transmit signal information to the onboard receiver which takes this information and use triangulation to calculate the aircraft's exact location. The GPS receiver compares the time a signal was transmitted by a satellite with the time it was received. The time difference tells the GPS receiver how far away the satellite is. When this is combined with distance measurements from 4 or more satellites, the receiver can determine the aircraft's exact location (latitude, longitude and altitude) and display it on the unit's electronic map.


Satellite Navigation




1. The left and right of the rocker switch is used to select between the various pages within one of the groups.

2. The top and bottom of the rocker switch is used to select between the various page groups: NAV, WPT, FPL, or NRST. With the on-screen cursor enabled, the rocker switch allows you to move the cursor about the page.

3. The Procedures button allows you to add instrument approaches to your flight plan. When using a flight plan, available procedures for your arrival airport are offered automatically. Otherwise, you may select the desired airport, then the desired procedure.

4. The QUIT button is used to erase information or cancel an entry. Press and hold this button to immediately display the Default NAV page, regardless of which page is currently displayed.

5. and 6. The IN and OUT buttons allows you to select the desired map scale (i.e. zoom the view in or out.)

7. The DIRECT TO button provides access to the direct-to function, which allows you to enter a destination waypoint and establishes a direct course to the selected destination.

8. The ROUTE button allows you to see and follow a flight plan created using the Flight Planner, and to access instrument approaches.

9. The TERRAIN button allows you to add a graphical depiction of the terrain to the Default NAV page and to the Map page.

10. The ENTER button is used to approve an operation or to complete data entry.

11. The CURSOR button displays the on-screen cursor. The cursor allows you to enter data and/or make a selection from a list of options.

12. The NEAREST button displays the Nearest Airports page. The Left rocker switch (1) steps through the other NRST pages.

13. The WAYPOINT indicator. Regardless of whether it is an en-route waypoint or your final destination, your next waypoint on your flight plan will be shown here

14. The BEARING indicator shows the direction from your current position to the next waypoint.


15. The COURSE TO STEER indicator gives the recommended direction to steer in order to reduce course error or stay on course. This, in helicopter flight, should correspond to your Bearing.

16. The ESTIMATED TIME OF ARRIVAL indicator provides the estimated time at which you should reach your destination waypoint, based upon current speed and heading.

17. The VERTICAL SPEED REQUIRED indicator provides you with the vertical speed necessary to descend or climb from current position and altitude to a defined target position and altitude, based upon your current ground speed.

18. The TRACK ANGLE ERROR (TKE) indicators shows the angle difference between the desired track and your current track.

19. The CROSS-TRACK ERROR (XTK) indicator shows you the distance you are off a desired course, left or right.

20. The DESIRED TRACK (DTK) indicator shows the desired course between the active from and to waypoints.

21. The TRACK (TRK) indicator shows you your ground track.

22. The DISTANCE (DIS) indicator shows the distance from where you are to your next waypoint. This uses the great circle distance, which in helicopter flight, has a negligible difference from straight line distance.

23. The FLIGHT MAP.

24. The map ZOOM factor, displayed in nautical miles.

25. Your aircraft position relative to the flight map.

26. Your GROUND SPEED.

27. This indicator displays whether the DTK is to your left or right.

28. The ESTIMATED TIME ENROUTE indicator displays the expected time for you to reach your next waypoint at current speed and heading.


You can find out a lot more about using FS2004 GPS in the Learning Center that is a part of FS2004. For further study you can download a selection of GPS simulators to see how they work in the real world. Garmin provides several for their product line. You can obtain them from http://www.garmin.com/include/SimulatorPopup.html.