flight routes? potential bug or (ahem) pilot error

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gariac
Posts: 31
Joined: Sun Jan 13, 2013 6:25 am

flight routes? potential bug or (ahem) pilot error

Post by gariac » Thu Jul 03, 2014 9:30 pm

First the background. Lately I have been getting odd ICAO codes. These codes have very slow speed and are always on the ground. They use the callsign OPS. It is a guess that perhaps KSFO has put some mode-s on ground vehicles. Nobody is really sure. The reason KSFO is suspected is all the ICAO/registrations are reserved by KSFO. If anyone really cares, here they are:
OPS11
http://registry.faa.gov/aircraftinquiry ... rtxt=308QX

OPS8
http://registry.faa.gov/aircraftinquiry ... rtxt=306QX

OPS12
http://registry.faa.gov/aircraftinquiry ... rtxt=309QX

OPS4
http://registry.faa.gov/aircraftinquiry ... rtxt=303QX

OPS1
http://registry.faa.gov/aircraftinquiry ... rtxt=300QX

OPS2
http://registry.faa.gov/aircraftinquiry ... rtxt=302QX

OPS9
http://registry.faa.gov/aircraftinquiry ... rtxt=307QX

OPS3
http://registry.faa.gov/aircraftinquiry ... rtxt=305QX
The callsigns and ICAO are consistent. The altitude is always on the ground.

Now for the weird part. I noticed a callsign FM1. It goes to a reserved registration, but not at KSFO. There are a few FM callsigns:
FM1
http://registry.faa.gov/aircraftinquiry ... rtxt=103XB

FM2
http://registry.faa.gov/aircraftinquiry ... rtxt=104XB

FM3
http://registry.faa.gov/aircraftinquiry ... rtxt=105XB

FM6
http://registry.faa.gov/aircraftinquiry ... rtxt=108XB

FM10
http://registry.faa.gov/aircraftinquiry ... rtxt=112XB

FM11
http://registry.faa.gov/aircraftinquiry ... rtxt=113XB

FM14
http://registry.faa.gov/aircraftinquiry ... rtxt=116XB

So lets say all these FM callsigns are just gibberish from a dump1090 that went mad. How does VRS then assign flights to these planes at don't exist as far as the FAA is concerned?

For example, ICAO A0247B is FM6. VRS found this route:
OJAM Amman-Marka, Amman, Jordan
LFPV Villacoublay-Vélizy (BA 107) Air Base, Villacoublay/Vélizy, France

For another example, ICAO A0448C is FM14. VRS found this route:
LFPV Villacoublay-Vélizy (BA 107) Air Base, Villacoublay/Vélizy, France
HDAM Djibouti-Ambouli, Djibouti City, Djibouti

CharlieAlpha
Posts: 63
Joined: Sat Mar 15, 2014 6:41 pm

Re: flight routes? potential bug or (ahem) pilot error

Post by CharlieAlpha » Fri Jul 04, 2014 7:49 pm

I am sure people will correct if I am wrong but I suspect VRS is being 'clever'.

Andrew has implemented some logic to help match callsign variations to routes - handling when leading zeros are omitted or added, for example so "ETD020" and "ETD20" resolve to the same correct route. I am sure there are other "fuzzy logic" matching rules implemented.

I guess in the case of "FM14" VRS is assuming "FM" refers to "Shanghai Airlines", because "FM" is the IATA code for that airline. It is then matching "FM14" with the callsign "CSH14" (because "CSH" is Shanghai Airlines ICAO code) and returning the route you list.

Hope this helps

Charlie

gariac
Posts: 31
Joined: Sun Jan 13, 2013 6:25 am

Re: flight routes? potential bug or (ahem) pilot error

Post by gariac » Sat Jul 05, 2014 6:05 am

I see what you mean, but callsigns can be just about anything, at least in the US. Occasionally they are a bit vulgar. I suppose a refinement would be to not add callsigns for aircraft that don't exist in the database.

CharlieAlpha
Posts: 63
Joined: Sat Mar 15, 2014 6:41 pm

Re: flight routes? potential bug or (ahem) pilot error

Post by CharlieAlpha » Sat Jul 05, 2014 2:59 pm

I guess the problem is two-fold
1) callsigns aren't tied to specific aircraft. Here in the uk (and I guess it is the same elsewhere) if, for example, an aircraft is on the London - Manchester shuttle route it may make 8 or more trips a day; each trip will have a different flight number and a different call-sign. If tomorrow a different aircraft is used on that route it will almost certainly use the same flight number(s) / call sign(s) as today's aircraft used.

2) as for excluding aircraft not in the database. VRS uses the basestation database installed on your machine as it reference for aircraft details. If there is a new aircraft it won't be in your database until you add it - be that manually, downloading an updated basestation file, using an automatic updater etc. I get my updates from the "Man TMA Overflights group" website but that issues updates at approximately month intervals (the most recent was 1 July). I will generally see 6 - 10 aircraft a month that aren't found in my version of the database. I either do web searches to find the details and add manually or wait for the update to populate the data.

Charlie

agw
Posts: 2248
Joined: Fri Feb 17, 2012 3:20 am

Re: flight routes? potential bug or (ahem) pilot error

Post by agw » Sat Jul 05, 2014 5:24 pm

It's cool if SFO are equipping ground vehicles with ADS-B :)

CharlieAlpha is correct - if it sees a callsign of FM1 then it will work backwards from that to a route, even though there's no route for FM1, by taking the steps he's outlined. It has to do this, pilots are not consistent in how they enter callsigns.

In 2.0.2 I added support for marking which aircraft are ground vehicles in BaseStation.SQB. I've just checked and unfortunately I still show routes for ground vehicles, I'll fix that for 2.0.3 - however it's still worth marking the ground vehicles as such in your BaseStation.sqb because they'll be shown with the correct marker on the map (assuming that they're transmitting positions) and be given a species of "Ground Vehicle". Their markers will not show the route, even if you have configured the markers to show routes. The route will only appear in the aircraft detail and list panels.

Ground vehicles are identified by their ICAO8643 code, which is in the IcaoTypeCode field in BaseStation.sqb. If you set this to -GND then VRS will assume that the aircraft is a ground vehicle, and similarly a code of -TWR tells it that it's a radar beacon.

If you are using a program to populate BaseStation.sqb, and that program is setting the IcaoTypeCode to something else for ground vehicles and radar beacons, then you can configure VRS to tell it what to look for. You need to create a text file in the VRS configuration folder called FakeModelCodes.txt and then copy & paste this into it:

Code: Select all

[GroundVehicleCodes]
-GND

[TowerCodes]
-TWR
Add your new codes to the appropriate section, one code per line. Anything after a # symbol is a comment, so if your code contains a hash then you're out of luck.

Ground vehicles are not shown on the map until you zoom in quite close. Large airports often have more ground vehicles than aircraft, showing the vehicles when you're zoomed out leads to the airport just becoming a maggot farm of follow me car icons.

gariac
Posts: 31
Joined: Sun Jan 13, 2013 6:25 am

Re: flight routes? potential bug or (ahem) pilot error

Post by gariac » Wed Jul 09, 2014 7:15 am

Actually I haven't got one position hit on any of the ground vehicles. I can't "see" SFO, though it isn't like I have a mountain between me and the airport. More like a molehill. I don't know how I'm getting the ground vehicle signals. I do get velocity and bearing, and some of these drivers have a lead foot, presuming they are actually on the tarmac.

I do plan on a road trip to get a better sniffing location.

I presume the ground vehicle transmitters are not as powerful as the aircraft transmitters. Well, let's hope so.

While the OPS callsigns have a FAA link to SFO, that is not the case for the FM tail numbers. But I have no position data on the FM hits either. Some of the sessions have hundreds of ADS-B hits, but never a position.

agw
Posts: 2248
Joined: Fri Feb 17, 2012 3:20 am

Re: flight routes? potential bug or (ahem) pilot error

Post by agw » Mon Jul 14, 2014 12:34 am

Have you set a receiver location that's reasonably close to your position (or the airport)? Ground positions are unlike airborne positions in that they can decode to one of 8 positions on the globe, so VRS needs to know the receiver location to decide which position to use. It just uses the one closest to the receiver. If you can see aircraft on the ground at the airport after they've landed but you don't see aircraft taking off until they're airborne then you're probably missing the receiver location.

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