VT Radio Astronomy Interference Mitigation Project

Virginia Tech Radio Astronomy Interference Mitigation Project

Playlist available on
Data repository: Repoman-rfcap

Steve Ellingson, Principal Investigator
Mike Buehrer, Co-PI
Jordan Budhu

Collaborators
Sean Hum, University of Toronto
Brad Davis, VT National Security Institute

Graduate Students
Trisha Bora (MS Thesis)
Joe Esser
William Howard
Hiten Kothari (MS Thesis)
Xinrui Li
Fatemeh Sadr
Ramonika Sengupta (MS Thesis)
Yugma Bharat Thakore
Alec Yip (MS Thesis)
Jet Yu

Undergraduate Research
Tom Anders
Joe Esser
Olivia Leonard
Adam Kimbrough
Alec Yip

SatTrack (2025 Undergrad Project)
L. Heller
J. Santana

RIS Design/Build/Test (2025 Undergrad Project)
A. Jellison
J. Nadeau
S. Squier
A. Tenorio

MOSAIC (2024 Undergrad Project)
J. Andrew
K. Klevar
P. Vangumalla

2023 Senior Design Team
J. Daigle
E. Duval
J. Jamison
S. Taliaferro
C. Van Horn

2022 Undergraduate Program
T. Anders
J. Awad
A. Alonso
Y. Dong
J. DiNiso
J. Velasquez

This is: https://ellingsonvt.info/raim/
Last update: Dec 30, 2025

The Radio Astronomy Interference Mitigation Project was established at Virginia Tech in 2019 to advance the state-of-the-art in techniques for mitigation of interference that affects radio astronomy and other passive uses of the radio spectrum.

Here is a snapshot/overview of the entire project as of Jan 2023: Techniques for Observing in the Presence of Satellite Interference (This video necessarily excludes much detail, which can be found below.)

Interference Canceling for Improved Coexistence Between Passive and Active Radio Systems
This work is supported in part by National Science Foundation Grant ECCS-2029948
Introduction Video (YouTube). Now several years old.
Poster presented at NSF SWIFT PI meeting, May 13, 2024

Electronically-Reconfigurable Surfaces for Improved Coexistence Between Radio Astronomy and Satellite Communications Systems
This work is supported in part by National Science Foundation Grant AST-2128506
Introduction Video (YouTube). Now several years old.
Demonstration of Null Tracking (YouTube)
Poster presented at NSF SWIFT PI meeting, May 13, 2024
Can be implemented using flat panel reflectarrays attached to existing reflectors: Yip Thesis, 2024
System overview & animation by Jordan Budhu and Mike Buehrer, June 2025
Works when the reconfigurable surface is mounted on a subreflector! See arXiv:2512.23530, 2025

News: June 2025
Our paper "Design of Rim-Located Reconfigurable Reflectarrays for Interference Mitigation in Reflector Antennas" was selected for IEEE Trans. Antennas & Propagation's "Special Article Collection on Antennas and Propagation for Space Applications". Here is a nice video summary by IEEE TAP.

Journal Papers (reverse chronological order)

X. Li, R.M. Buehrer, S.W. Ellingson, "Parametric Methods for Coherent Time-domain Canceling of Radio Frequency Interference," Publ. Astron. Soc. Pac., 137, 044502. DOI: 10.1088/1538-3873/ada186. (April 11, 2025)
J. Budhu, S.V. Hum, S.W. Ellingson, R.M. Buehrer, "Design of Rim-Located Reconfigurable Reflectarrays for Interference Mitigation in Reflector Antennas" IEEE Trans. Ant. & Prop., Vol. 72, No. 4, April 2024, pp. 3736-41. DOI: 10.1109/TAP.2024.3352250. Preprint: arXiv:2305.18199 [eess.SY]. (May 29, 2023; Dec 21, 2023)
S.W. Ellingson & R.M. Buehrer, "Coherent Time-Domain Canceling of Interference for Radio Astronomy" (2022), Publ. Astron. Soc. Pac., 134, 114505. DOI: 10.1088/1538-3873/ac9b92.
S.W. Ellingson and R. Sengupta, "Sidelobe Modification for Reflector Antennas by Electronically-Reconfigurable Rim Scattering", IEEE Ant. & Wireless Prop. Let., Vol. 20, No. 6, Jun 2021, pp. 1083-7. DOI: 10.1109/LAWP.2021.3072536. Preprint.

Papers in Conferences & Other Meetings (reverse chronological order)

F. Sadr, N.-R. Hui, J. Budhu, S.V. Hum, and S.W. Ellingson, "Applications of Reflectarray Technology for Radio Astronomy Interference Mitigation", European Conference on Antennas and Propagation (EuCAP), Stockholm, Sweden, March 2025. DOI: 10.23919/EuCAP63536.2025.10999892.
X. Li, R.M. Buehrer, S.W. Ellingson, "An Improved Weight Selection Algorithm for Interference Mitigation in Paraboloidal Reflector Antennas with Reconfigurable Rim Scattering", 2024 IEEE Military Communications Conference (MILCOM), Washington, DC, Oct 2024. DOI: 10.1109/MILCOM61039.2024.10773626.
J. Budhu, S.V. Hum, S. Ellingson, and R.M. Buehrer, "Loading Rims of Radio Telescopes with Reconfigurable Reflectarrays for Adaptive Null-Steering", URSI National Radio Science Meeting, Boulder CO, Jan 2024. DOI: 10.23919/USNC-URSINRSM60317.2024.10464936. Video.
S.W. Ellingson, R.M. Buehrer, T. Anders, X. Li (2024). "New Results on Mitigation of Satellite Interference by Coherent Time-Domain Canceling". URSI National Radio Science Meeting, pp. 276. doi:10.23919/USNC-URSINRSM60317.2024.10464804.
R. Sengupta & S.W. Ellingson, "Adaptive Antenna Pattern Modeling for Interference Mitigation in Radio Astronomy", IEEE Int'l Conf. on Antenna Measurements & Applications (CAMA), Genoa, Italy, Nov 2023, DOI: 10.1109/CAMA57522.2023.10352823.
S.V. Hum, S.W. Ellingson & R.M. Buehrer, "Toward Electronically Reconfigurable Rims for Reflectors in Radio Astronomy", URSI General Assembly & Sci. Sym., Sapporo, Japan, Aug 2023.
S.V. Hum, S.W. Ellingson & R.M. Buehrer, "Reflectarray Concept for Interference Mitigation in Radio Astronomy", IEEE Int'l Ant. & Prop. Sym., Portland OR, July 2023. DOI: 10.1109/USNC-URSI52151.2023.10237818.
R. Sengupta & S.W. Ellingson, "Effect of Antenna Pattern on Time-Domain Canceling of Interference from Satellites", IEEE Int'l Ant. & Prop. Sym., Portland OR, July 2023. DOI: 10.1109/USNC-URSI52151.2023.10237408.
R.M. Buehrer & S.W. Ellingson, "Weight Selection for Pattern Control of Paraboloidal Reflector Antennas with Reconfigurable Rim Scattering", IEEE Aerospace Conf., Big Sky, MT, March 2023. DOI: 10.1109/AERO55745.2023.10115669. Presentation.
S.W. Ellingson & R.M. Buehrer, "Techniques for Observing in the Presence of Satellite Interference", URSI National Radio Science Meeting, Jan 2023, Video.
R.M. Buehrer & S.W. Ellingson, "Pattern Control for Reflector Antennas Using Electronically-Reconfigurable Rim Scattering", 2022 IEEE Ant. & Prop. Sym., July 2022. DOI: 10.1109/AP-S/USNC-URSI47032.2022.9886543. Video.

Preprints (reverse chronological order)

S.W. Ellingson & A.J. Yip, "Sidelobe Modification for an Offset Gregorian Reflector System using a Reconfigurable Intelligent Surface-Equipped Subreflector". Preprint: arXiv:2512.23530, [astro-ph.IM] (Dec 29, 2025).
X. Li & R.M. Buehrer, "Neural Network-Assisted RIS Weight Optimization for Spatial Nulling in Distorted Reflector Antenna Systems". Preprint: arXiv:2512.21253, [eess.SP] (Dec 24, 2025).
X. Li & R.M. Buehrer, "On the Limits of Coherent Time-Domain Cancellation of Radio Frequency Interference". Preprint: arXiv:2512.18427, [eess.SP] (Dec 20, 2025).
X. Li, R.M. Buehrer & S.W. Ellingson, "RIS-Aided Spatial Nulling: Algorithms, Analysis, and Nulling Limits". Preprint: arXiv:2512.18426, [eess.SP] (Dec 20, 2025).
J.M. Santana, L. Heller & R.M. Buehrer, "SatTrack: Software for Evaluating Satellite Interference and Rim-Based Interference Mitigation Using a Reconfigurable Parabolic Antenna". Preprint: arXiv:2512.17016, [astro-ph.IM] (Dec 18, 2025; Dec 22, 2025).
H.P. Kothari & R.M. Buehrer, "Interference Mitigation using U-Net Autoencoder based system". Preprint: arXiv:2512.13844, [eess.SP] (Dec 15, 2025).
T. Anders, H.P. Kothari & R.M. Buehrer, "On the Ability of Deep Learning to Detect Signals with Unknown Parameters". Preprint: arXiv:2512.13542, [eess.SP] (Dec 15, 2025).
H.P. Kothari & R.M. Buehrer, "Interference Mitigation Recommender System using U-Net Autoencoders". Preprint: arXiv:2512.13533, [eess.SP] (Dec 15, 2025).
S. Ellingson, "A Simple L-Band Spectrum Measurement System", Zenodo, Jan 2025, https://doi.org/10.5281/zenodo.14711769.
W. Howard, R.M. Buehrer & S.W. Ellingson, "Open and Closed-Loop Weight Selection for Pattern Control of Paraboloidal Reflector Antennas with Reconfigurable Rim Scattering". Preprint: arXiv:2308.16339, [eess.SP] (Aug 30, 2023; 27 Feb 2024).
S.W. Ellingson, "Characterization and Mitigation of Sinusoidal Carrier Modulation Signals by Short-Term Sinusoidal Analysis", arXiv:2004.03649 [eess.SP]. (Apr 7, 2020)

Theses (reverse chronological order)

H.P. Kothari, On the Use of Deep Learning Models for Interference Detection and Mitigation, MS thesis, Dec 2025, ETD.
A. Yip, Rim-Mounted Reconfigurable Surfaces for Interference Nulling in Focus-Fed Axisymmetric Reflector Antenna Systems, MS thesis, May 2024, ETD, Video.
T. Bora, Multi-Layered Dual-Band Dual-Polarized Reflectarray Design Toward Rim-Located Reconfigurabable Reflectarrays for Interference Mitigation in Reflector Antennas, MS thesis, May 2024, ETD.
R. Sengupta, Adaptive Pattern Modeling for Large Reflector Antennas, MS thesis, July 2022, ETD, Video

Memos, Reports, etc. (reverse chronological order)

A. Jellison, J. Nadeau, S. Squier & A. Tenorio, "Reconfigurable Intelligent Surface" (undegraduate design project report), Tech. Rep., Aug 2025. Contact Brad Davis for access.
F. Sadr, J. Budhu & S. Ellingson, "Dual-Band Reflectarray Project Report: Spring 2025", Tech. Rep., May 2025, PDF.
R. Sengupta & S. Ellingson, "A Fast Approximate Method for Calculating the Gain and Pattern of an Axisymmetric Circular Prime-fed Paraboloidal Reflector Antenna", Tech. Rep., Aug 28, 2021. PDF
S. Ellingson, "Satellite Tracking Data via the Command Line Interface of PREDICT", Tech. Rep., Aug 15, 2021. PDF

"EM Spectrum Science and Management: Science Fundamentals" course module playlist

"EM Spectrum Science and Management: Engineering Fundamentals" course module playlist