ADS-B reception in the kitchen: lovely!

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jan_olieslagers
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Joined: 24 Jun 2006, 08:34
Location: Vl.Brabant
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ADS-B reception in the kitchen: lovely!

Post by jan_olieslagers » 19 Mar 2019, 17:23

After much hesitation, I ordered the required hardware, and - after setting it up - installed the dump1090 software. This was not a trivial exercise, but the results are nice.

* set up the Raspberry and its Raspbian O/S was a trivial exercise, but then I am a Linux sysadmin by trade, and have a nice hardware environment running, including a DHCP server.
* attaching the RTL stick was the easiest of all - literally plug and play.
* installing the dump1090 software was a bit of work, and might be hard on some. It involved using the much-dreaded "make install" and "make" commands; but - contrary to several earlier experiences - everything went as smooth as could be. I basically followed the instructions on https://www.satsignal.eu/raspberry-pi/dump1090.html, they're not perfect but quite quite good
* the result is enchanting, even if it takes some effort to unearth the full potential. As it is, I get an http page with a little map (with Google Maps for a background) of received information, and a text-mode overview which I much prefer. But that is just me, of course, an old-fashioned command-line-oriented sysadmin :)

First observations:
* located more or less on a long final to EBBR 25R, I receive information from inbound planes as far away as Dendermonde or Liege; and that is with the receiver antenna in the house, though on the first floor; might get better if I can manage an outdoor location for it but it will not be for tomorrow
* remarkable how busy the skies are in early morning, and how calm otherwise; writing this at 16:16 UTC, I see only 5 planes reported; this morning there were more than 20
* some planes show up with very very little information, and I think these are the most interesting, at least to some
* for one example, I observed a BAF999 (it was not 999 but it did be BAF) which I suspect to be Belgian Air Force; it did not show up on FlghtRadar24 - I presume they filter these flights, like they filter many more
* what fascinated me most is the many occurrences of Squawk 1000 - KLM flights using this very often, but I also saw it on BEL, AUA, AFR, and several more. Is there a special meaning to squawk 1000?

modeS
Posts: 15
Joined: 19 Jun 2018, 10:55

Re: ADS-B reception in the kitchen: lovely!

Post by modeS » 19 Mar 2019, 18:59

Mode A 1000 is one of the non-discrete mode A codes (others being 2000, 7000,...) and this one can only be assigned by ATC if the aircraft is equipped with a mode S transponder and the filed route from current position until parking position at destination will completely take place in mode S operational airspace.

It makes the ATM system correlate the aircraft track and filed flightplan based on the mode S aircraft identification transmitted by the mode S transponder instead of correlating by means of a discrete mode A code. This technique has been implemented years ago because there are not enough discrete mode A codes available to manage the air traffic in Europe.

It basically goes as follows:
  • Company files flightplan
  • Eurocontrol processes the flightplan and checks for the necessary conditions for mode A 1000 eligibility (mode S transponder, filed route in mode S operational airspace,...)
  • If all necessary conditions are fulfilled, Eurocontrol adds the flag 'IFP/MODESASP' in field 18 of the flightplan
  • Eurocontrol distributes the flightplan to all applicable ANSPs
  • If the flight is eligible for mode A 1000 the ATS unit giving IFR clearance at the origin will see the flag IFP/MODESASP in the flightplan and hence be able to assign mode A 1000 instead of a discrete mode A code.
EBBU airspace was among the first in Europe to be mode S operational. On aerodrome level Brussels EBBR is currently the only Belgian airport where mode 1000 can be assigned. The regional airports will likely follow in future. Airports like Schiphol, Frankfurt, Munich, Vienna and several more including their airspaces are mode S operational as well, hence the several mode 1000 transmits you are tracking.

jan_olieslagers
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Re: ADS-B reception in the kitchen: lovely!

Post by jan_olieslagers » 20 Mar 2019, 08:32

Thanks!

jan_olieslagers
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Re: ADS-B reception in the kitchen: lovely!

Post by jan_olieslagers » 23 Mar 2019, 11:30

More questions come up as I try to decode the received data. Subject of today: flight designators. As I understand it, an ICAO flight designator consists of
* the icao identification of the operator, always in 3 characters A-Z
* 1, 2 or 3 digits 0-9
* 1 or 2 characters A-Z
The reason I ask is that there are 2 more formats possible: either the registration - as is common for smaller craft - or a mix of airline identification and (part of) registration - I've not seen this as yet. So that any flight designator received that does not match the above pattern would be a registration.

Could anyone confirm - or improve?

modeS
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Joined: 19 Jun 2018, 10:55

Re: ADS-B reception in the kitchen: lovely!

Post by modeS » 24 Mar 2019, 13:33

Below are the regulations for civil aircraft in Belgium and Luxembourg (for detailed info please check AIP ENR 1.10 §1.5.2). Aircraft identification (maximum 7 characters) on the ATC flightplan and thus the one that shall be transmitted by the mode S transponder consists of one of the following two options:
  • operating agency ICAO designator followed by minimum one and maximum four alphanumeric characters (e.g. JAF6KG)
  • aircraft registration (only alphanumeric characters) (e.g. OOSFG)

When it comes to radiotelephony there are several options (the last format you mention being one of them):
  • JAF6KG - BEAUTY SIX KILO GOLF (radiotelephony designator being used, most common)
  • JAF6KG - JULIETT ALFA FOXTROT SIX KILO GOLF (not common, but valid)
  • OOSFG - OSCAR OSCAR SIERRA FOXTROT GOLF (common, can be abbreviated to OSCAR FOXTROT GOLF on initiation by ATC)
  • OOSFG - BEELINE OSCAR OSCAR SIERRA FOXTROT GOLF (not common, but valid, provided that OPR/BEL is in field 18, can be abbreviated as well by ATC)

DIBO
Posts: 530
Joined: 28 Mar 2009, 14:54

Re: ADS-B reception in the kitchen: lovely!

Post by DIBO » 24 Mar 2019, 13:47

modeS wrote:
24 Mar 2019, 13:33
  • OOSFG - BEELINE OSCAR OSCAR SIERRA FOXTROT GOLF (not common, but valid, provided that OPR/BEL is in field 18, can be abbreviated as well by ATC)
Used to be way that Sabena used it callsigns for many years, even when all other airlines had long switched to flightnos.: SABENA OSCAR OSCAR SIERRA TANGO ALFA (ex. for the first of the 727 series).

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