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 15:42, 15 October 2017 by Stuart (Talk | contribs) (Layers)

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]


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-like implementation - the canvas map UI is really just a way to display it. [2]

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.[3]


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.[4]

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.[5]

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.[6]


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. [7]


Depending on how we deal with this challenge, the question is whether that means that the usefulness of FlightGear will also gradually taper off. [8]

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.[9]

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.[10]

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.[11]

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. [12]

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)[13]

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.[14]

that would certainly be possible - the code retrieving the data is pretty trivial and porting the Nasal code to python or some other script should be straightforward.[15]

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 [16]


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.[17]


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.[18]

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.[19]

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. Many of these would also be good to have for other avionics/GUI dialogs, including the NavDisplay framework, which is currently re-implementing this functionality separately, i.e. not yet using MapStructure.

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 Page Notes
Flight Plan Route Lines RTE Requires styling 190
Flight Plan Route Waypoints RTE Requires styling 190
Rivers/Lakes VFRChart 148 Currently using downloaded raster from web. Perhaps generate similarly to Atlas, or could be vector data from scenery.
Topography Data VFRChart Synthetic 145 Height-map at chart-resolution. Perhaps generate similarly to Atlas?
International Borders 148 Vector data from scenery?
Track Vector 156 Forward looking display of track. Look-ahead time selectable.
Navigation Range Ring 158 Straightforward extension of APS.
Fuel Range Ring 159 Straightforward extension of APS.
Terrain Data 364 Should be straightforward, with exception of obstacles. Profile view also required.
Traffic TFC 394,423 Various options, each with different iconography and data displayed.
Airways VFRChart 154 Needs to be replaced with vector data
NEXRAD 282 Heaps of weather data with complex symbology.
XM Lightning Data WXR Change to symbol for lightning? 294 Optional
Airports APT, RWY Require re-style based on size 149, 163
Runway Labels RWY Needs to be added to RWY symbol. Should be straightforward
Restricted OpenAIP 182 Currently using downloaded rasters. Would be better replaced with vector data
MOA (Military) OpenAIP 182 Currently using downloaded rasters. Would be better replaced with vector data
User Waypoints
Latitude/Longitude Grid GRID
NAVAIDs APT, VOR, FIX, NDB Requires styling 162
Class B Airspaces/TMA OpenAIP 182 Currently using downloaded rasters. Would be better replaced with vector data
Class C Airspaces/TCA OpenAIP 182 Currently using downloaded rasters. Would be better replaced with vector data
Class D Airspaces OpenAIP 182 Currently using downloaded rasters. Would be better replaced with vector data
Other Airspaces/ADIZ OpenAIP 182 Currently using downloaded rasters. Would be better replaced with vector data
TFRs 310
Obstacles OpenAIP 182 Currently using downloaded rasters. Would be better replaced with vector data
Land/Country Text 148 Currently using raster data from web. Replace with POI?
Cities VFRChart 148 Currently using raster data from web. Perhaps generate similarly to Atlas, or could be vector data from scenery.
Roads VFRChart 148 Currently using raster data from web. Requires vector data from scenery
Railroads VFRChart 148 Currently using raster data from web. Requires vector data from scenery
State/Province Boundaries VFRChart 148 Currently using raster data from web. Requires vector data from scenery
River/Lake Names VFRChart 148 Currently using raster data from web. Replace with POI?
Selected Altitude Intercept Arc 161 Simple extention to APS
SafeTaxi (Optional) RWY, TAXI 493 We don't currently have the data to display taxiway identifier or holding points
ChartView (Optional) 503 Rendering of PDFs. Might be possible to integrate with NaviGraph chart data?
FliteChart (Optional) 521 Rendering of PDFs. Might be possible to integrate with NaviGraph chart data?

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. [20]

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.[21]

Existing work

Avionics / Cockpits

  • zvk1000
  • extra500 / Avidyne Entegra R9000

Nasal / Canvas

C++

  • Synthetic Vision element for rendering viewmgr views to a Canvas
  • Canvas PDF element - for rendering PDF files (think EFB functionality)

Structure

Design

Resources

Related

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