[Scan-DC] Interesting "test" airplane showing up on ADS-B

[Andrew Clegg]

Hey Eric --


Thanks for the info. I'm still learning a lot about ADS-B, and experimenting with the raw message output from dump1090. I had no idea the rate of messages that would be received. I'm getting a message decode about every 14-20 milliseconds during the day, covering out to over 250 nm. Not bad for my antenna in the windowsill. Anyway, thanks for the additional details.


Andy


________________________________
From: Eric C. Carlson <ecarlson at gmail.com>
Sent: Sunday, October 23, 2016 3:32 PM
To: Andrew Clegg
Cc: Scan-DC at mailman.qth.net
Subject: Re: [Scan-DC] Interesting "test" airplane showing up on ADS-B

They are a big FAA contractor for NextGen ATC, ADS-B, etc. so it could
be a lot of things.  The Mode S specification includes categories for
identification of ground vehicles, fixed positions/tethered
obstructions, etc. (even parachute/skydivers).  At least at airports
with ground surveillance, you will see Mode S codes assigned to the
ground-based surface monitoring equipment (the locations of which are
emitted in the FAA's ASDE-X data feed).  The FAA does multilateration
as one of several methods for tracking ground targets so this may be
related.  The hex code ADFC2C is above the range allocated for civil
aircraft but still in the USA range.  I see similar codes used for the
fixed ground positions on airfields and ground vehicles that are Mode
S equipped (there are a number of codes that are reused between
different airports).

-Eric

On Sat, Oct 22, 2016 at 9:46 AM, Andrew Clegg
<andrew_w_clegg at hotmail.com> wrote:
> I just started running ADS-B on my Raspberry Pi and feeding data to Flightaware.com. One of the interesting decodes is a "plane" with the Ident of "MTRTEST3," which is stationary, and corresponds in Google Earth to a location coincident with one of MITRE's office buildings in Tysons. The ICAO hex code is ADFC2C.
>
>
> I guess MITRE is running an experimental ADS-B transmitter on its roof? Anyone know what specifically they're experimenting with?
>
>
> I checked the FCC's experimentals and there's nothing registered for that site at 1090 MHz. MITRE could be working off an NTIA authorization, which wouldn't show up in the FCC's database. Looks like they've been pretty active in developing the whole ADS-B technology, so it makes sense they would have an experimental system. Kind of odd to have a stationary airplane show up in the data though!