IEEE - Aerospace and Electronic Systems - July 2023 - 54

dump1030: Open-Source Plug-and-Play Demodulator/Decoder for 1030 MHz Uplink
Figure 8.
Conceptual design using single-station (GS0) or multiple-station (GS0+GS1) deployments of dump1030 for finding direction (SSR1) and
exact GPS location (SSR2) of 1030-MHz interrogators using sectoral antennas and Multilateration MLAT (GS0+GS1)-in this example in
the center is depicted a 6-sector antenna ofGS0, and depiction ofGS1 is minimized.
we present a high-level conceptual model of achieving,
implementing, and using free and open-source (FOSS)
implementation ofTCAS.
IMPROVED LOCALIZATION OF 1030-MHZ STATIONS
AND SSRS
dump1030 coupled with multiple RTL-SDR connected
to sector-directed array antenna (e.g., six sectors 60each)
could be an effective tool to detect the exact location of
" hidden " SSR stations. Such " hidden " SSR stations could
be either clandestine or belong to a military adversary;
therefore, their detection could be helpful in certain situations.
Moreover, several ground stations (GS), implemented
on Raspberry Pi or laptops, could be used
essentially to perform multilateration (MLAT) on 1030MHz
signals, hence accurately pinpointing the location of
such 1030-MHz SSR interrogation stations. In Figure 8,
we present a high-level conceptual model on how single
and multiple GS (coupled with GPS and numerous sectoral
antennas connected to individual dump1030 instances)
can be used to achieve precise localization of 1030MHz
SSR interrogation stations.
To demonstrate and evaluate this approach in practice,
we have tried to acquire a 6-sector antenna supporting
Mode S bands 1030 and 1090 Mhz,6 however it proved to
be prohibitively expensive for a research lab experiment.
Therefore, the current pricing and limited offerings
prompt further research on open-hardware and open6The
" 6 Sector Squitter, Ground Station Antenna Part Number:
530300-100 " costs around US$60,000. Available: https://www.
dbsant.com/antennas/6-sector-squitter-ground-station-antenna/.
54
firmware active antennas that could potentially allow
research labs, such as ours to build these antennae at a
price range of several hundred and no more than a couple
of thousand USD/EUR.
COMPLIANCE CHECKS OF 1090-MHZ TRANSPONDERS
As part of dump1030 project, besides the source codes,
we also release reference 1030-MHz interrogation signals.
In very well-controlled labs (such as detailed in [12]), the
researchers can send the interrogation signals to some particular
1090-MHz transponder under test, and then
observe its compliance to functional (i.e., responds or
not), performance (e.g., response within required timeslot,
is response signal correct and compliant), and cybersecurity
[28], requirements. Moreover, dump1030 can play
the receiving end of the response to a 1030-MHz interrogation,
thus assisting the compliance test and validation,
both from functional, operational, and cybersecurity perspectives.
For example, the inclusion of dump1030 into
an avionics test lab, such as the one proposed by Strohmeier
et al. [12] could be immediate and straightforward. In
summary, in this context our dump1030 project (including
reference 1030-MHz interrogation signals) is a valuable
all-in-one 1030-MHz toolset.
APPLICATIONS IN LOW-COST DRONES AND UAV/UAS
SYSTEMS
Industry-grade aerospace vehicles and aircraft will likely
rely on commercial-grade and certified implementations
of 1030-MHz receivers and decoders (e.g., certified
TCAS). However, such TCAS systems cost tens (and
IEEE A&E SYSTEMS MAGAZINE
JULY 2023

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