Hi fellow wiki editors!

To help newly registered users get more familiar with the wiki (and maybe older users too) there is now a {{Welcome to the wiki}} template. Have a look at it and feel free to add it to new users discussion pages (and perhaps your own).

I have tried to keep the template short, but meaningful. /Johan G

FG1000

From FlightGear wiki
Revision as of 14:54, 15 October 2017 by Hooray (Talk | contribs) (Offline mode)

Jump to: navigation, search
This article is a stub. You can help the wiki by expanding it.
Stuart pushed some changes to fgdata with OpenStreetMap, OpenAIP and VFRMap layers for the Canvas Map Layer system, which can be seen on the canvas map dialog. They use a generic Slippy Map OverlayLayer Map Layer. Additional web-based mapping can be trivially added by creating a new lcontroller. See Nasal/Canvas/map/OpenAIP.lcontroller for an example.Stuart also added a Web Mercator Projection to the Canvas Map support.The wiki will be updated shortly.[1]

Motivation

1rightarrow.png See Canvas_News#Moving_map.2FRNAV_discussion for the main article about this subject.

The enormous variety in current glass flight decks means we really need to think of a new way of defining glass cockpit layouts.[2]


The airspace system is in the process of changing drastically [...] this isn't just a matter of throwing up a canvas showing some GPS waypoints and a magenta line. Modern navigators are astoundingly-complex devices — probably an order of magnitude more lines of code than FlightGear itself — and even their basic flight planning algorithms and databases (e.g. fly-by waypoints vs fly-over waypoints, open vs closed approach procedures, transitions into RNAV approaches, etc.) are far beyond the scope of anything we've tried, and we'd also need an up-to-date database far more complex than the ones we have now. Once you get to the extra features, like FIS-B weather or TIS-B traffic info over ADS-B, or TAWS (terrain alerting), we're probably in way over our heads trying to emulate even the simplest general-aviation IFR GPS.

This may help folks understand what the G1000 is all about: http://static.garmincdn.com/pumac/190-00498-07_0A_Web.pdf Writing a G1000 isn't that hard. Writing a feature complete G1000 is a ton of work. [3]


Depending on how we deal with this challenge, the question is whether that means that the usefulness of FlightGear will also gradually taper off. [4]

Instead of just making one-off tweaks like the consumer sims did, we (as a team) emulated entire systems like the vacuum, pitot-static, and electrical systems, so that failures would be realistic. In the RNAV age, we need to do the same thing; it's just that it's a bigger job. FlightGear will still be great for people who want to practice the mechanical parts of flying (e.g. crosswind wheel landings in a Cub), but will slip further and further behind for people who want to use it for real IFR practice.[5]

Performance

it's a lot of work to code all these displays which someone has to do, but there's no reason to assume it'd be hopeless performance-wise.[6]

we need to be realistic here: The G1000 is a fairly significant piece of computer hardware that we're going to emulate. It's not going to be "free" particularly for those on older hardware that's already struggling. However, hopefully we can offload a chunk of the logic (route management, autopilot/flight director) to the core, and do things like offline generation of terrain maps to minimie the impact.[7]

Background

1rightarrow.png See Complex Canvas Avionics for the main article about this subject.

Challenges

Route Manager

that's exactly the kind of device James hopes the new code can support. He's read the G1000 pilot's manual, and *thinks* that nearly all the functions can be provided by the current GPS code It would be great if people could look over the current GPS features and indicate any pieces you think might be missing - additional commands, additional search features, extra data, or anything really. [8]

tile servers

Please keep in mind that most tile servers discourage bulk downloads. For the whole planet,oomlevel 8 is approx. 67k files, at zoomlevel 9 you have 265k, level 10 has a little over one million tiles. And one would probably want to go up to level 15 (roughly 1e9 files)[9]

Offline mode

would it be possible to provide an offline tool to pre-fetch a region, like TerraMaster, or terrasync.py? Call me old-fashioned or paranoid, but I don't want FG to go online and do stuff automatically, I prefer downloading what I need manually so that I know what gets onto my harddisk. Also - think of all the people with poor home internet which might have larger bandwidth only in a library elsewhere.[10]

Navdata

we need some better data sources, especially with direct routing replacing airways in many areas, and having airspace data would help the map displays, but the current API is specifically designed to support G430, G1000 and similar class devices. Adding RNAV approaches is eminently doable, see the the RNavController base class which the GPS/FMS layer uses to allow new waypoint / route segments to define how they are flown and drive CDIs [11]


Getting the algorithms right, and keeping the data up to date every 7 weeks (we have only a tiny sliver of that data currently), is going to be much more of a challenge. I expect that it's probably an order of magnitude more complicated than our current flight dynamics (etc.), so we'd have to grow our contributor base, and find funding to pay at least Curt (and maybe a couple of others) full time to manage the project. Note that that's what has happened for other complex FOSS projects, like office suites and browsers, which generally end up working through a foundation, rather than our current relaxed circle-of-friends arrangement. The reason it's so much harder now is that the software *is* the product for GPS navigators, FMSs, etc. (unlike with older avionics, where the hardware was the main thing). That means that emulating even a simple unit like the GTN 650 or GNS 430W is almost difficult as building one, so we're trying to keep up with armies of full-time software developers at Garmin, Avidyne, etc.[12]


According to the Route Manager wiki page, we already have support for SID/STAR data provided from Navigraph, which is released on the AIRAC cycle, and costs a pretty small amount (9 EUR for a single download of FMS data, or 90 EUR per year) Given the relatively low cost, I don't think that we as an organiation want to get into trying to digitize data ourselves just to make it open-source or public domain. Particularly given the low cost of a download. We might want to digitize the STAR/SIDs for the default airport with each release so there are some approaches available for those who don't want to purchase the data.[13]

Plan

Stuart has been in contact with the author (Sébastien MARQUE) of the ZKV-1000. While he himself doesn't plan to implement a G1000, he's very happy for it to be developed in that direction. Stuart's broad plan is to make a copy of this in fgdata or fgaddon, and use it as the basis for a G1000, taking the opportunity to use Richard's MFD code and making as generic pages as possible for other glass cockpit applications.[14]

Layers

Following is the list of layers displayed by the G1000 system (see page 153 of the 190-00498-07 Rev. A), and mapping to the equivalent MapStructure Layer.

Layer MapStructure Layer Status Notes
Flight Plan Route Lines
Flight Plan Route Waypoints
Rivers/Lakes
Topography Data
International Borders
Track Vector
Navigation Range Ring
Fuel Range Ring
Terrain Data
Traffic
Airways
NEXRAD
XM Lightning Data
Airports
Runway Labels
Restricted
MOA (Military)
User Waypoints
Latitude/Longitude Grid
NAVAIDs
Class B Airspaces/TMA
Class C Airspaces/TCA
Class D Airspaces
Other Airspaces/ADIZ
TFRs
Obstacles
Land/Country Text
Cities
Roads
Railroads
State/Province Boundaries
River/Lake Names

Status

1rightarrow.png See Canvas_News#G1000_.26_MapStructure_improvements for the main article about this subject.

Stuart wants to build a set of layers for a G1000 implementation - the canvas map UI is really just a way to display it. [15]

When he gets the chance he's going to write a quick wiki article on the MapStructure layers that need to be implemented for the G1000 implementation. That might help to coordinate efforts as well.[16]


October 2017

Stuart committed some changes to update the Select Airport dialog to use Canvas MapStructure Layers to display airport information, rather than the now deprecated map layers. The change should be largely transparent to end users - the only significant change is that your can display navigation symbols. This is all part of a long-term effort to provide the building blocks for a Garmin G1000 - these layers could be used for the airport display on the MFD, and could easily be combined with the APS layer to show a moving aircraft.[17]

September 2017

Stuart added some new Nasal Canvas MapLayers to support Slippy Maps, as used by most web-based mapping services such as openstreetmap. This allows us to display sectional charts (for the US - vfrmap.com), and airspace information (courtesy of openaip.org), as well as a openstreetmap data. The canvas Map dialog has been updated to support these layers. Map data is retrieved over http and cached locally.[18]

Existing work

Structure

Resources

Related

References
  1. stuart  (Sep 28th, 2017).  Re: Canvas G1000 .
  2. Robin van Steenbergen  (Oct 2nd, 2007).  Re: [Flightgear-devel] Glass cockpit and external gauges. .
  3. geneb  (Jul 3rd, 2017).  Re: [Flightgear-devel] RFD: FlightGear and the changing state of air navigation .
  4. David Megginson  (Jul 3rd, 2017).  [Flightgear-devel] RFD: FlightGear and the changing state of air navigation .
  5. David Megginson  (Jul 4th, 2017).  Re: [Flightgear-devel] RFD: FlightGear and the changing state of air navigation .
  6. Thorsten Renk  (Jul 4th, 2017).  Re: [Flightgear-devel] RFD: FlightGear and the changing state of air navigation .
  7. Stuart Buchanan  (Jul 4th, 2017).  Re: [Flightgear-devel] RFD: FlightGear and the changing state of air navigation .
  8. James Turner  (Oct 22nd, 2009).  Re: [Flightgear-devel] ZKV500 GPS instrument; (New?) GPS code bug .
  9. Torsten Dreyer  (Sep 29th, 2017).  Re: [Flightgear-devel] Canvas MapLayer for OpenStreetMap, OpenAIP, VFR Sectionals .
  10. Thorsten Renk  (Sep 29th, 2017).  Re: [Flightgear-devel] Canvas MapLayer for OpenStreetMap, OpenAIP, VFR Sectionals .
  11. James Turner  (Jul 4th, 2017).  Re: [Flightgear-devel] RFD: FlightGear and the changing state of air navigation .
  12. David Megginson  (Jul 4th, 2017).  Re: [Flightgear-devel] RFD: FlightGear and the changing state of air navigation .
  13. Stuart Buchanan  (Jul 4th, 2017).  Re: [Flightgear-devel] RFD: FlightGear and the changing state of air navigation .
  14. Stuart Buchanan  (Aug 1st, 2017).  [Flightgear-devel] G1000 (was Re: Nasal property lookup performance) .
  15. Stuart Buchanan  (Oct 1st, 2017).  Re: [Flightgear-devel] Canvas MapLayer for OpenStreetMap, OpenAIP, VFR Sectionals .
  16. Stuart Buchanan  (Oct 2nd, 2017).  Re: [Flightgear-devel] Canvas MapLayer for OpenStreetMap, OpenAIP, VFR Sectionals .
  17. Stuart Buchanan  (Oct 13th, 2017).  [Flightgear-devel] Updated Select Airport dialog .
  18. Stuart Buchanan  (Sep 28th, 2017).  [Flightgear-devel] Canvas MapLayer for OpenStreetMap, OpenAIP, VFR Sectionals .