NAV\GPS_operation

Roberts Awesome GPS/NAV Checklist

One tip - it's best not to leave SOXCDI running for more than 20 minutes or so when you are sitting still on the ramp (this usually arises pre-flight). It can lock up in those circumstances, probably due to some subtlety involving graphically rendering a huge number of aircraft positions in almost exactly the same spot. This problem does not occur during flight, only on the ground. it will happily run for 12 hours or more once you're airborne.

One option is to start up SOXCDI during your preflight procedures, get it set up as you want, and then exit the program and start it up again around the time you start engines. When you restart it the second time, it will remember all the settings, including the sequence file you gave it. So if you gave it a sequence file from a thumb drive, best for the thumb drive to still be inserted when you restart. Also, when you restart it, it will usually cause the corruption of the external sound card (Matt knows about this). You fix that by removing the sound card's USB connector for a couple of seconds and then reinserting it. The oscilloscope window gives you the feedback you need to do this.

To setup the Marconi signal generators

• • Power on function generator

  • Push "REC'L" button followed by "01" (push "0" then "1")

    • This should automatically set the right carrier frequency of 108.1 MHz if not the:

    • Push "CARR FREQ" followed by "108.1" and then "MHz"

  • Push "RF LEVEL" followed by "1000" (push "1" followed by "0" three times) and then "uV" (micro-V)

• As a side note, we programmed all the function generators to do the same thing with memory settings "00" or "01". So the user can press "RECL" and then "00" or "01" and get the same result. Oddly, the memory settings do not set the RF level.

Here is an example "sequence file" for input into SOXCDI, SOXMap, and/or SimpleFMS:

PABR 71.2854475 -156.7660019 400 0

PABR 71.2854475 -156.7660019 400 0

PABR 71.2854475 -156.7660019 400 0

SEB1 73.469072 -131.820170 250 0

BGOSC 77.0000000 -140.0000000 250 0

NBGOSD 73.9998000 -140.1076830 400 0

PABR 71.2854475 -156.7660019 400 0

Each sequence file *must* have ".sequence" at the end of the filename. If it does not, SOXMap/SOXCDI/SimpleFMS will not recognize the file.

This flight plan starts and ends at the Barrow, AK airport (ICAO designation PABR), and flies to three waypoints in the pack ice in the southeastern Beaufort Sea named SEB1, BGOSC, and NBGOSD in that order. Sequence files always list a mission's waypoints in the sequential order in which they are intended to be flown. Note that the first waypoint *must* be repeated three times, as in the example above. This reflects a legacy software capability to insert divert airfields, but the simplest approach most of the time is to just repeat the initial waypoint three times.

Each waypoints records consists of 5 words:

1. alphanumeric waypoint name (6 characters or less)

2. decimal latitude in degrees (-90 to 90)

3. decimal longitude in degrees (0 to 360 or -180 to 180 accepted interchangeably)

4. expected groundspeed between this waypoint and the next in the sequence in knots

5. minutes required to execute a maneuver between this waypoint and the next in addition to the direct flight time required. This is generally used to account for 180 turns, stacks, and many other potential maneuvers. Leave at 0 if you don't know what else to do.

SOXCDI, SOXMap and SimpleFMS all allow the user to load sequence files via their "File" menus, similar to most commercial software packages. Thus the user simply needs to select a method to load their waypoints into the navigation computer's filesystem. This can be via the aircraft network, or via a removable USB drive on the computer itself. Another option is to insert the USB drive into the KVM switch's USB port, which in many cases (depending on installation) is more accessible than the USB ports of the computer. If the "focus" of the KVM switch is set to the proper computer (by pressing and holding the selector switch), the computer should mount the USB drive and it should be a normal part of the filesystem, and the sequence files should be visible to SOXCDI/SOXMap/SImpleFMS.

When you operate SOXCDI, most of it's going to be pretty straightforward. Two things, both under the "Nav" menu, are a bit more complex:

1. The "Navigation technique" always defaults to "Great circle". Leave it there, do not select "rhumb line" unless you really understand what that means.

2. The "Waypoint mode" always defaults to its setting the last time the program was run. This setting governs the manner in which the current waypoints are activated. I strongly suggest you operate this in the "Manual" mode, meaning that the active waypoints (the white ones and the ones that are providing the steering signal to the autopilot) are always exactly as you set them via the "Prev WP" and "Next WP" buttons at top right. The other settings auto-update the active waypoints according to different algorithms and the plane's position and heading, and that can get you into trouble in many circumstances.

Startup

1. Turn on overhead power source (60 Hz) and verify light is on.

2. Plug in UPS for GPS and NAV racks. Move white cords so they won’t accidentally be pulled.

3. Turn on UPS for GPS and NAV racks. Wait for green light to stop blinking.

4. Turn on Sorensen AC/DC converter for GPS and NAV racks.

5. Check Sorensen to make sure no current is being drawn.

6. Put toggle on rear of station to ‘on’ position for GPS and NAV racks.

7. Turn on Javad receivers on GPS rack.

8. Turn on Ashtech and Eurocard receivers on the GPS rack.

9. Make sure KVM switch on GPS rack is set to ‘1’.

10. Boot computer on left side of GPS rack. Wait until it has booted before going to next step.

11. Switch KVM switch on GPS rack to ‘2’.

12. Boot computer on right side of GPS rack. Do not switch the KVM switch until computer has booted.

13. Make sure KVM switch on NAV rack is set to ‘2’.

14. Boot computer on right side of NAV rack. Do not switch the KVM switch until computer has booted.

15. Wait until red light goes away and start data collection on both Javad receivers on GPS rack.

16. Turn on signal generator on rear of NAV rack.

17. Press ‘RECL’ button, then ‘00’. Display should then say: ‘108.1 MHz, 55% smaller window’.

18. Press ‘RF level‘ button.

19. Type ‘1000’.

20. Push ‘µV’.

21. On GPS rack, set KVM switch to ‘1’ and start linlogger for Computer 1.

22. For location, type ‘dc8z’.

23. Press start. Check other tabs to make sure it is working.

24. On GPS rack, set KVM switch to ‘2’ and start linlogger for computer 2.

25. For location, type ‘dc8e’.

26. Press start. Check other tabs to make sure it is working.

27. On Computer 2 for the NAV rack, start SOXCDI.

Shutdown

1. On Computer 2 for the NAV rack, stop and close any running NAV programs.

2. Shut down Computer 2 on NAV rack.

3. Turn off signal generator on rear of NAV rack.

4. If spare Ashtech on NAV rack is on, turn it off.

5. Wait for ~1 hour for data collection.

6. Make sure KVM switch on GPS rack is set to ‘1’.

7. Stop linlogger on Computer 1 on GPS rack.

8. Make sure KVM switch on GPS rack is set to ‘2’.

9. Stop linlogger on Computer 2 of GPS rack.

10. Stop Javad data collection on GPS rack.

11. Pull data from both Javads to portable medium(s).

12. Pull data from Asthtech and Eurocard to portable medium(s).

13. Turn off both Javads on GPS rack.

14. Turn off Ashtech and Eurocard receivers on GPS rack.

15. Make sure KVM switch on GPS rack is set to ‘1’.

16. Shut down Computer 1 on GPS rack.

17. Make sure KVM switch on GPS rack is set to ‘2’.

18. Shut down Computer 2 on GPS rack.

19. Put toggles on backs of GPS and NAV racks to the ‘off’ position.

20. Make sure amp reading is 0 for Sorensens on GPS and NAV racks.

21. Turn off Sorensens on GPS and NAV racks.

22. Turn off UPS on GPS and NAV racks.

23. Unplug UPS on GPS and NAV racks.

24. Turn off overhead ship’s power.