Junzi Sun, Ph.D.

My other sites

mode-s.org openap.dev

Aircraft Surveillance

My research interests in aircraft surveillance include topics such as Mode S, ADS-B, and VHF signals. Mode S is a secondary surveillance radar (SSR) system that can acquire aircraft identification, altitude, and other information. ADS-B is a surveillance technology that broadcasts aircraft position and other information to ground stations and other aircraft. VHF signals are used by aircraft to communicate with air traffic control and other aircraft.

Highlights

pyModeS: An Open-source Python Mode-S Decoder
pyModeS is a Python library for decoding and encoding Mode S (including ADS-B) messages. It is an open-source project that receives great support and contributions from the aviation community. This Python package can be imported into an existing Python project, and it is also used as a standalone tool to view and save live traffic data.
The 1090 Megahertz Riddle: A Guide to Decoding Mode S and ADS-B Signals
An open-access book for researchers, engineers, and students on decoding ADS-B and common Mode S messages. It covers the background (primary and secondary radar, Mode A/C, Mode S, ADS-B) and the hardware and software needed to receive the signals. The 17 core chapters walk through each message type in detail, with Python examples throughout.

Related publications

  1. tangram in action – Practical use cases for real-time open aviation research
    Conference 2025
    Olive, Xavier ; Cheung, Yan Lok ; and Sun, Junzi
    In Proceedings of the 15th SESAR Innovation Days, Lake Bled, Slovenia
    Copy Olive, X., Cheung, Y. L., & Sun, J. (2025, December). tangram in action – Practical use cases for real-time open aviation research. Proceedings of the 15th SESAR Innovation Days, Lake Bled, Slovenia.
    Copy 
    @inproceedings{olive2025tangramaction,
  title = {tangram in action -- Practical use cases for real-time open aviation research},
  author = {Olive, Xavier and Cheung, Yan Lok and Sun, Junzi},
  booktitle = {Proceedings of the 15th SESAR Innovation Days, Lake Bled, Slovenia},
  year = {2025},
  month = dec,
  link = {https://www.sesarju.eu/sites/default/files/documents/sid/2025/papers/SIDs_2025_paper_99-final.pdf},
  tag = {surv}
}
  2. OpenSky Report 2023: Low Altitude Traffic Awareness for Light Aircraft with FLARM
    Conference 2023
    Olive, Xavier ; Strohmeier, Martin ; Sun, Junzi ; and Tresoldi, Giorgio
    In Proceedings of the 41th Digital Avionics Systems Conference
    Copy Olive, X., Strohmeier, M., Sun, J., & Tresoldi, G. (2023, September). OpenSky Report 2023: Low Altitude Traffic Awareness for Light Aircraft with FLARM. Proceedings of the 41th Digital Avionics Systems Conference. https://www.cs.ox.ac.uk/files/14442/3052.pdf
    Copy 
    @inproceedings{olive2023opensky,
  title = {OpenSky Report 2023: Low Altitude Traffic Awareness for Light Aircraft with FLARM},
  author = {Olive, Xavier and Strohmeier, Martin and Sun, Junzi and Tresoldi, Giorgio},
  booktitle = {Proceedings of the 41th Digital Avionics Systems Conference},
  year = {2023},
  month = sep,
  url = {https://www.cs.ox.ac.uk/files/14442/3052.pdf},
  tag = {surv},
  award = true
}
  3. Preliminary Design and Capacity Study of Automatic Dependent Surveillance for Drones
    Conference 2022
    Vlaskin, Aleksandr ; Sun, Junzi ; and Hoekstra, Jacco
    In Proceedings of the 12th SESAR Innovation Days, Budapest, Hungary
    Copy Vlaskin, A., Sun, J., & Hoekstra, J. (2022, December). Preliminary Design and Capacity Study of Automatic Dependent Surveillance for Drones. Proceedings of the 12th SESAR Innovation Days, Budapest, Hungary.
    Copy 
    @inproceedings{vlaskin2022preliminary,
  title = {Preliminary Design and Capacity Study of Automatic Dependent Surveillance for Drones},
  author = {Vlaskin, Aleksandr and Sun, Junzi and Hoekstra, Jacco},
  booktitle = {Proceedings of the 12th SESAR Innovation Days, Budapest, Hungary},
  year = {2022},
  month = dec,
  tag = {surv},
  link = {https://research.tudelft.nl/files/151906542/sids22_paper_107.pdf}
}
  4. ADS-B Signal Verification Using a Coherent Receiver
    Conference 2021
    Huygen, Wouter ; Sun, Junzi ; and Hoekstra, Jacco
    In Proceedings of 9th OpenSky Symposium
    Copy Huygen, W., Sun, J., & Hoekstra, J. (2021, November). ADS-B Signal Verification Using a Coherent Receiver. Proceedings of 9th OpenSky Symposium.
    Copy 
    @inproceedings{huygen2021adsb,
  title = {ADS-B Signal Verification Using a Coherent Receiver},
  author = {Huygen, Wouter and Sun, Junzi and Hoekstra, Jacco},
  booktitle = {Proceedings of 9th OpenSky Symposium},
  year = {2021},
  month = nov,
  tag = {surv},
  link = {https://doi.org/10.3390/engproc2021013004}
}
  5. OpenSky Report 2021: Insights on ADS-B Mandate and Fleet Deployment in Times of Crisis
    Conference 2021
    Sun, Junzi ; Olive, Xavier ; Strohmeier, Martin ; Schäfer, Matthias ; Martinovic, Ivan ; and Lenders, Vincent
    In Proceedings of the 40th Digital Avionics Systems Conference
    Copy Sun, J., Olive, X., Strohmeier, M., Schäfer, M., Martinovic, I., & Lenders, V. (2021, October). OpenSky Report 2021: Insights on ADS-B Mandate and Fleet Deployment in Times of Crisis. Proceedings of the 40th Digital Avionics Systems Conference.
    Copy 
    @inproceedings{sun2021opensky,
  title = {OpenSky Report 2021: Insights on ADS-B Mandate and Fleet Deployment in Times of Crisis},
  author = {Sun, Junzi and Olive, Xavier and Strohmeier, Martin and Sch{\"a}fer, Matthias and Martinovic, Ivan and Lenders, Vincent},
  booktitle = {Proceedings of the 40th Digital Avionics Systems Conference},
  year = {2021},
  month = oct,
  link = {https://www.cs.ox.ac.uk/files/12934/dasc_2021_adsb_mandate_fleet_deployment.pdf},
  tag = {surv}
}
  6. The 1090 Megahertz Riddle: A Guide to Decoding Mode S and ADS-B Signals
    Book 2021
    DOI: 10.34641/mg.11
    Sun, Junzi
    TU Delft OPEN Publishing
    Copy Sun, J. (2021). The 1090 Megahertz Riddle: A Guide to Decoding Mode S and ADS-B Signals (2nd ed.). TU Delft OPEN Publishing. https://doi.org/10.34641/mg.11
    Copy 
    @book{sun1090mhz,
  author = {Sun, Junzi},
  title = {The 1090 Megahertz Riddle: A Guide to Decoding Mode S and ADS-B Signals},
  publisher = {TU Delft OPEN Publishing},
  year = {2021},
  month = may,
  edition = {2},
  isbn = {978-94-6366-402-8},
  doi = {10.34641/mg.11},
  tag = {surv},
  link = {https://doi.org/10.34641/mg.11}
}
  7. Mode S Transponder Comm-B Capabilities in Current Operational Aircraft
    Conference 2020
    DOI: 10.3390/proceedings2020059004
    Sun, Junzi ; Vû, Huy ; Olive, Xavier ; and Hoekstra, Jacco
    In Multidisciplinary Digital Publishing Institute Proceedings
    Copy Sun, J., Vû, H., Olive, X., & Hoekstra, J. (2020). Mode S Transponder Comm-B Capabilities in Current Operational Aircraft. Multidisciplinary Digital Publishing Institute Proceedings, 59(1), 4. https://doi.org/10.3390/proceedings2020059004
    Copy 
    @inproceedings{sun2020modes,
  title = {Mode S Transponder Comm-B Capabilities in Current Operational Aircraft},
  author = {Sun, Junzi and V{\^u}, Huy and Olive, Xavier and Hoekstra, Jacco},
  booktitle = {Multidisciplinary Digital Publishing Institute Proceedings},
  volume = {59},
  number = {1},
  pages = {4},
  year = {2020},
  month = nov,
  doi = {10.3390/proceedings2020059004},
  link = {https://doi.org/10.3390/proceedings2020059004},
  tag = {surv}
}
  8. Analyzing Aircraft Surveillance Signal Quality at the 1090 Megahertz Radio Frequency
    Conference 2020
    Sun, J ; and Hoekstra, JM
    In Proceedings of the 9th International Conference for Research in Air Transportation
    Copy Sun, J., & Hoekstra, J. M. (2020, September). Analyzing Aircraft Surveillance Signal Quality at the 1090 Megahertz Radio Frequency. Proceedings of the 9th International Conference for Research in Air Transportation.
    Copy 
    @inproceedings{sun2020rf,
  title = {Analyzing Aircraft Surveillance Signal Quality at the 1090 Megahertz Radio Frequency},
  author = {Sun, J and Hoekstra, JM},
  booktitle = {Proceedings of the 9th International Conference for Research in Air Transportation},
  year = {2020},
  month = sep,
  link = {https://research.tudelft.nl/files/85733420/ICRAT2020_paper_25.pdf},
  tag = {surv},
  award = true
}
  9. pymodes: Decoding Mode S Surveillance Data for Open Air Transportation Research
    Journal 2019
    DOI: 10.1109/TITS.2019.2914770
    Sun, Junzi ; Vû, Huy ; Ellerbroek, Joost ; and Hoekstra, Jacco
    IEEE Transactions on Intelligent Transportation Systems
    Copy Sun, J., Vû, H., Ellerbroek, J., & Hoekstra, J. (2019). pymodes: Decoding Mode S Surveillance Data for Open Air Transportation Research. IEEE Transactions on Intelligent Transportation Systems. https://doi.org/10.1109/TITS.2019.2914770
    Copy 
    @article{sun2019pymodes,
  title = {pymodes: Decoding Mode S Surveillance Data for Open Air Transportation Research},
  author = {Sun, Junzi and V{\^u}, Huy and Ellerbroek, Joost and Hoekstra, Jacco},
  journal = {IEEE Transactions on Intelligent Transportation Systems},
  doi = {10.1109/TITS.2019.2914770},
  year = {2019},
  month = may,
  publisher = {IEEE},
  tag = {surv},
  link = {https://research.tudelft.nl/files/103003967/08718517.pdf}
}

© Copyright 2026 Junzi Sun