By Julian Avisenis
Contents:
1. Introduction
2. Improvements in this version
3. Features
4. Installation
A. Installation of
the system as a replacement of the default Microsoft GPS
B. Installation
where no INS or GPS is already present
C. Note to developers
5. Manual programming
6. “Automatic” programming
7. Operation notes
8. The “fast track” to using the INS
1.
Introduction
This Inertial Navigation System (INS) is especially intended to be of assistance to all those pilots who enjoy flying classic airliners, particularly on long flights. If correctly used, the INS should provide a more realistic means of long-haul navigation than the GPS, which postdates many of these classic aircraft. It may also be installed in more contemporary aircraft. All that is required is for the system to be accurately programmed with all the desired "waypoints" relevant to the desired flight. This may be done the hard way, the coordinates of each waypoint being sequentially entered, checked and saved. In the real world, this certainly takes up a lot of time. Most flight simmers don’t have the assistance of ground staff or a First Officer to help with this task. Such help would be welcome, and I have "simulated" this, allowing automatic programming of the INS directly from a valid flight plan. The unit is loosely based on the well-known Delco Carousels, but has extended waypoint capacity and is easier to operate, allowing long flights without having to monitor or adjust the unit.
2. Improvements in this version
· Accuracy in following flight plans. No INS will consistently guide you exactly through every waypoint. Some are
more accurate than others. This simulated INS now has improved accuracy, particularly in the timing of the
switch from one waypoint to the next.
· FSSound.dll (a part of the sound routine, courtesy of Daniel Steiner) was omitted from the previous version. It is
now included.
3. Features
· Up to 99 waypoints may be entered and stored.
· Entry mistakes are easily corrected.
· Waypoints may be entered manually, or may be automatically converted and entered from a valid FS2004 flight
plan.
· Waypoints are saved to a WAYPOINTS.DAT file for future use.
· Waypoints may be changed or edited, even if they are “active”. This means you can edit a waypoint even while
you are flying towards it using the INS.
· Displays coordinates of current position.
· Displays coordinates of active waypoint.
· Displays current heading in degrees.
· Displays distance to active waypoint in nautical miles.
· Displays ground speed in knots.
· Displays estimated time to active waypoint in hours and minutes.
· Waypoint switching may be set to automatic or manual. See later for details.
· Automatic correction for crosswinds (within reason!) and “drift”. Accuracy is therefore quite high.
· Warning is given when aircraft is approximately 2 minutes from active waypoint.
· If you have not landed by the time the last waypoint is reached (asleep?) the unit will keep the aircraft circling
that last waypoint.
·
Warning is given if unit is operating on battery rather than
generator power.
· The unit is powered by engine number one’s generator, so it works in single or multi-engine aircraft.
· If no generator is available , battery power will suffice.
4. Installation
Please read and follow this carefully. Basic knowledge of windows operations and text editing is needed. I will not be held responsible for mistakes. There are two main scenarios concerning installation. Here are both in detail:
A. Installation of the system as a replacement of the default Microsoft GPS:
· Copy the gauge (JMA_INS.gau) into the “Gauges” folder which is in the main "Flight Simulator 9" folder.
(Usually in "Microsoft Games", in "Program Files").
· Also copy FSSound.dll from the included “FSSound” folder to the “Modules” folder in the main “Flight
Simulator 9” folder if you do not already have it in there.
· Open the “Aircraft” folder which is also in the main "Flight Simulator 9" folder.
· Locate and open the aircraft folder of the particular aircraft which you wish to equip with the INS system.
· Open the panel subfolder and locate
the panel.cfg file. Make a backup of it for
safety/uninstallation.
· Open the panel.cfg file using a text editor such as WordPad or Notepad.
· Search for the Main Panel gauge entry. This is usually under [Window00], but not always. It will have visible=1 in
its parameters.
· Add the following line at the end, making sure that you number it one more than the last gauge number that
was already there, e.g.:
before the addition:
gauge56=SimIcons!Avionics Icon, 72, 111
gauge57=SimIcons!GPS Icon, 86, 111
becomes:
gauge56=SimIcons!Avionics Icon, 72, 111
gauge57=SimIcons!GPS Icon, 86, 111
gauge58=JMA_INS!INS_UPDATE,12,1,1,1 ß This adds an invisible part of the gauge to the main
panel.
Note the numbering as “gauge58” in this case.
· I have included this line in the text file “example.txt” for convenience. Copy and paste it in and change the
xx to the appropriate gauge number.
· Now locate the GPS entry (in this case it is [Window02] but it will vary from aircraft to aircraft) and replace the
lines below the [Windowxx] entry with the new entry (also in the “example.txt” file), e.g.:
before alteration:
[Window02]
size_mm=456,378
window_size=0.5
position=8
BACKGROUND_COLOR=0,0,0
VISIBLE=0
ident=GPS_PANEL
gauge00=fs9gps!gps_500,0,0 ß The gauge which is to be replaced.
becomes:
[Window02] ß This remains unchanged.
size_mm=175,160 ß New code from
here on.
window_size=1.0
position=8 ß You can
experiment with different numbers here, from 0 to 8. Usually 7 or 8 will be
best.
BACKGROUND_COLOR=0,0,0
VISIBLE=0 ß If you change
this to VISIBLE=1, this window will be visible on loading the panel.
ident=GPS_PANEL ß Note that the
GPS identity remains unaltered.
gauge00=JMA_INS!INS,0,0,175,160 ß This adds the gauge itself to the panel.
· The main reason for using the existing GPS
entry and identity is so that you can use the existing GPS SimIcon
on your panel
to display or hide the INS gauge.
· Save the changes and exit.
· All done!
B. Installation where no INS or GPS is already present:
· This is not as easy as replacing a GPS with the INS, and some trial and error will be needed.
· Copy the gauge (JMA_INS.gau) into the “Gauges” folder which is in the main "Flight Simulator 9" folder.
(Usually in "Microsoft Games", in "Program Files").
· Also copy FSSound.dll from the included “FSSound” folder to the “Modules” folder in the main “Flight
Simulator 9” folder if you do not already have it in there.
· Open the “Aircraft” folder which is also in the main "Flight Simulator 9" folder.
· Locate and open the aircraft folder of the particular aircraft which you wish to equip with the INS system.
· Open the panel subfolder and locate the panel.cfg file. Make a backup of it for safety/uninstallation.
· Open the panel.cfg file using a text editor such as WordPad or Notepad.
· Add a new window entry to the [Window Titles] section near the top of the page (provided in the “example.txt”
file), e.g.:
before the addition:
[Window Titles]
window00=Main Panel
window01=Radio Stack
window02=Throttle Quadrant
window03=Compass
becomes:
[Window Titles]
window00=Main Panel
window01=Radio Stack
window02=Throttle Quadrant
window03=Compass
window04=GPS ß This adds a new window for
the INS to occupy. Note the numbering as “window04”, i.e. one more
than the last entry number prior to the
addition.
· Now search for the Main Panel gauge entry (usually under [Window00], but not always. It will have visible=1 in
its parameters).
· First, add a default GPS SimIcon to your aircraft main
panel. This will be needed to display or hide the INS
gauge as required. (Otherwise you have to display/hide it by
pressing Shift-5 on your keyboard in this case, or
Shift-(window number+1) in general).
It is possible that the panel already has some SimIcons
or SimIcons1024 (either may be used, the SimIcons1024
are larger), as shown in this example from the end of a Main Panel section of a panel.cfg file:
gauge21=SimIcons1024!Electrical Panel Icon,
716, 748
gauge22=SimIcons1024!Other Controls Icon,
741, 748
gauge23=SimIcons1024!Clock Icon,
766, 748
Note the columns of numbers. The first gives the position of each SimIcon in pixels from the left hand side of
the panel. In this case they are 25 pixels
apart. The second gives the position of each SimIcon
in pixels from
the top of the panel. Add the GPS SimIcon as follows (provided in the “example.txt”
file):
gauge21=SimIcons1024!Electrical Panel Icon,
716, 748
gauge22=SimIcons1024!Other Controls Icon,
741, 748
gauge23=SimIcons1024!Clock Icon,
766, 748
gauge24=SimIcons1024!GPS Icon,
791, 748 ß Added line.
In this example I have placed the GPS SimIcon
in line with the others, 748 pixels from the top of the panel and
25 pixels to the right of its neighbour (766+25=791).
You may have to experiment to find the best position. If
there are no SimIcons
on the panel at all, even more experimentation and adjustment will be needed to
find a
good position for the icon.
· Now add the following line at the end, making sure that you number it one more than the last gauge number
that was already there, e.g.:
before the addition:
gauge21=SimIcons1024!Electrical Panel Icon,
716, 748
gauge22=SimIcons1024!Other Controls Icon,
741, 748
gauge23=SimIcons1024!Clock Icon,
766, 748
gauge24=SimIcons1024!GPS Icon,
791, 748 ß The line which you have already added.
becomes:
gauge21=SimIcons1024!Electrical Panel Icon,
716, 748
gauge22=SimIcons1024!Other Controls Icon,
741, 748
gauge23=SimIcons1024!Clock Icon,
766, 748
gauge24=SimIcons1024!GPS Icon,
791, 748 ß Already added line.
Gauge25=JMA_INS!INS_UPDATE,12,1,1,1 ß This adds an invisible part of the gauge to the main
panel.
Note the numbering as “gauge25” in this case.
· I have included this line in the text file “example.txt” for convenience. Copy and paste it in and change the
xx to
the appropriate gauge number.
· Finally, add the GPS (actually our INS) entry (provided in the “example.txt” file) after the last of the [Windowxx]
entries (before any [Fixed Windowxx] or other entries such as [Vcockpitxx], [Color], etc.), e.g.:
[Window04] ß Make sure the
number corresponds to the [Window Titles] number (see above), 04 in this
case.
size_mm=175,160
window_size=1.0
position=8 ß You can
experiment with different numbers here, from 0 to 8. Usually 7 or 8 will be
best.
BACKGROUND_COLOR=0,0,0
VISIBLE=0 ß If you change
this to VISIBLE=1, this window will be visible on loading the panel.
ident=GPS_PANEL ß We will use
the GPS identity to make things easier.
gauge00=JMA_INS!INS,0,0,175,160 ß This adds the gauge itself to the panel.
· Save the changes and exit.
· Done!
C. Note
to developers:
· Should you decide to use this gauge in a panel, you are free to install it as you like. Please note that it has
two subgauges. INS_UPDATE must always be on a panel which is permanently open, usually the main panel, or
else the gauge will not work. INS itself can go on any panel.
5. Manual programming
Start by running FS2004. Create a flight plan using the flight planner which
is part of FS2004. If you don't know how to do this, it is well explained in
the "
· Select "WPT", or waypoint mode, using the mode selection knob at the left of the instrument.
· Push "SET". The display will flash.
· If the INS already contains waypoints, you will now be overwriting them.
· Enter the coordinates of the first waypoint, checking that it is the first waypoint, and not your point of departure,
or you will be flying round in circles! Enter very carefully (easy to make mistakes!) using the keypad at the lower
right corner of the instrument. The order is vital: first "N" or "S" for North or South, then the digits in order, not
forgetting zeros. (Example: S0092102. This is South 9 degrees, 21 minutes and 2 seconds.) Continue by entering
"W" or "E" and the required digits. If you make a mistake, use the "CLEAR" key to erase one digit at a time.
· Please note that some keys have both a letter and a number. Don’t worry about this. Selection of letter or number
is automatic as appropriate.
· Push "INSERT" to save, but only once you have checked your entry.
· Push "WPT INC" to move to the second waypoint, push "SET" and enter and save the next pair of coordinates as
above. Continue the process until all waypoints are entered.
· If you discover a mistake once you have saved a waypoint, you will have to enter that whole waypoint again. (But
fortunately, not the whole plan!)
· Use the "LAST WPT" key followed by "WPT INC" to return to the first waypoint. (Simply, "WPT INC" moves ahead
one waypoint at a time, "LAST WPT" followed by "WPT INC" takes you back to the beginning. So, you can
advance one waypoint at a time, but can only go back to the first waypoint.)
6. “Automatic” programming
As above, you need a saved flight plan created with the aid of the flight
planner which is part of FS2004. Again, if you don't know how to do this, it is
well explained in the "
· Minimise (Alt+Tab keys) or exit FS2004.
· Open your "My Documents" folder and then open the "Flight Simulator Files" subfolder. Locate the desired saved
plan. It is always a ".PLN" file.
· Copy and paste (not cut and paste!) the plan to the main "Flight Simulator 9" folder. (Usually in "Microsoft
Games", in "Program Files").
· Rename the plan "PLAN" (in upper case as shown, but without the quotation marks). Don't change the ".PLN"
extension, or the plan will be unusable.
· Open the plan using WordPad. Be sure to tick the "Always use the selected program to open this type of file" box
for future ease of use. Ensure that the first waypoint (waypoint.0) is the first waypoint, and not your point of
departure. If it is the departure point, simply delete that entire line and save.
· Now go back to your aircraft and double click on the lower left screw on the faceplate of the INS unit. Voila! The
plan is entered.
· The coordinates will automatically be saved in the main "Flight Simulator 9" folder in the correct format as a "WAYPOINTS.DAT" file. The "PLAN.PLN" file may therefore be deleted if you wish. I often save the "WAYPOINTS.DAT" files of "favourite" flight plans in a separate folder (with saved maps, charts, weather or ".WX" files, the .PLN file etc.) for backup and later use. When required, simply copy the appropriate "WAYPOINTS.DAT" file to the main "Flight Simulator 9" folder (overwriting any previous one). Occasionally, I may have both a "WAYPOINTS.DAT" file for the outbound flight and a "PLAN.PLN" for the return in the "Flight Simulator 9" folder at the same time. The INS will always use the "WAYPOINTS.DAT" file. When I start the return trip I simply double click on that "active" screw as above and the "WAYPOINTS.DAT" file will be overwritten with the new coordinates for the return flight. Theoretically, in this way, you could have up to 198 waypoints available for the same session! However if you find that you are doing this, you are probably in urgent need of psychotherapy.
7. Operation notes
Selector in DIS/GS position Selector in HDG/TIME position
Here are some explanations concerning the buttons and selectors of this unit.
The mode selector in the "WPT" position displays the coordinates of the selected active waypoint as explained above. In "POS" the coordinates of the current aircraft position are displayed. "DIS/GS" gives the distance in nautical miles (left quartz display) to the selected or active waypoint (this must be less than 1000 nautical miles away) and the current ground speed in knots (right quartz display) of the aircraft towards the same waypoint. "HDG/TIME" displays the heading in degrees (left quartz display) to the selected waypoint, and an estimated time in hours and minutes (right quartz display) to that waypoint (this must be less than 1000 nautical miles away). Please note that the heading will vary slightly during the flight between waypoints, depending on drift due to winds aloft and other factors.
The remaining selector in the "AUTO" position will cause the INS to sequentially and automatically advance through all the waypoints. If "MAN" is selected, the waypoints have to be manually advanced using the "WPT INC" button. In this mode, the pilot has to judge the best time to switch to the next waypoint, allowing for the rate of turn of the aircraft. This will vary under different conditions. This facility may be useful if waypoints are relatively close together, but obviously, while navigating in this manner, the unit will need your constant attention. Please note that in this mode the INS will disengage if you do not advance the waypoint before you are within 0.5 nautical miles of the active waypoint. If this happens you will have to push the “HOLD” button to re-engage the unit.
The "WPT INC" button may be used to "skip ahead" at any stage of the flight, even in "AUTO" mode. Waypoint numbers may be advanced by left-clicking the "WPT INC" button or by using the mouse wheel while hovering over the button.
The "HOLD" button engages/disengages the INS. It will only engage the INS if the autopilot is on and in heading mode. This is most important. The unit will not operate in any other autopilot mode. The green light will illuminate when the INS is successfully engaged. Please note that if you should switch the autopilot off or disengage it from heading mode, the INS will automatically and immediately disengage. It is possible to plan the last stages of a flight so that the last leg crosses/intercepts an ILS signal at an appropriate angle (usually about 25 to 30 degrees) and suitably far out from the runway threshold (usually 15 nm or more). Simply switch the autopilot to approach mode just before the intercept, the INS will automatically disengage and the ILS/glide slope should be captured as usual.
The "LAST WPT" button will illuminate if pressed. Pressing the "WPT INC" button thereafter will extinguish the "LAST WPT" button and will take you back to the first waypoint.
The “SET” button will illuminate when pushed. Pushing it a second time will extinguish it. Waypoints may be entered while it is illuminated and the unit is in waypoint mode (selector on “WPT”).
The “CLEAR” button will erase one character at time while a waypoint is being entered.
Pressing the “INSERT” button will store waypoints once entered.
The number and letter buttons are self-explanatory. Please note that letters (N or S and E or W) are entered first on each quartz display and subsequent presses will automatically enter the numbers associated with those buttons rather than the letters.
The "BAT" light indicates that battery rather than generator power is being used. It will extinguish once the generators are "on line". This unit operates off battery power or generator number 1. (For developers: it uses the MASTER_BATTERY and GENERAL_ENGINE1_GENERATOR_ACTIVE token variables.)
The "ALERT" light will automatically illuminate when the aircraft is approximately 2 minutes from the selected waypoint.
8.
The “fast track” to using the INS
By now you have enough information to be able to use the INS. In summary, for the automatic method of use:
· Create a valid FS2004 flight plan. This will be a “.PLN” file, usually stored in the "Flight Simulator 9" subfolder in
the “My Documents” folder of your computer.
· Copy and paste this plan into the main
"Flight Simulator 9" folder.
· Rename the plan “PLAN” (without quotation marks). Be sure not to lose the “.PLN” extension.
· Open the plan using WordPad. Check that the first waypoint (waypoint.0) is the first waypoint, and not your point
of departure. Delete the whole line it if it is.
· Back in FS2004, double click on the lower left screw on the faceplate of the INS instrument. The plan should now
be automatically converted and entered.
· In order to engage the INS, first engage the autopilot and set it to heading mode.
· Engage the INS by pressing the "HOLD" button on the INS panel. Make sure the green light illuminates.
· The aircraft should now follow the programmed route.
· Disengage the INS by pressing "HOLD", disengaging heading mode on the autopilot or switching the autopilot off.