Franck Marchis

🚀✨ New publication alert! Excited to share our latest work on advancing drone-borne Ku-band #SAR #interferometry 🚁📡 📄 The paper “Accurate residual motion error estimation for high-frequency drone-borne #SAR interferometry” by Gerard Ruiz Carregal, Luis Eduardo Yam Ontiveros, G. Masalias, Eduard Makhoul Varona, PhD, Ruben Iglesias González, Marc Lort Cuenca, Antonio Heredia Moreno, Álex González Fabián, Giuseppe Centolanza, Azadeh Faridi, Dani Monells Miralles, Carlos López-Martínez and Javier Duro, a collaboration between DARES TECHNOLOGY and Universitat Politècnica de Catalunya, has just been published in IEEE Geoscience and Remote Sensing Society (GRSS) Transactions on Geoscience and Remote Sensing (TGRS). 🖥 Access the full paper here 👉 https://lnkd.in/dJFRPg2b 🔍 What’s it about? One of the biggest challenges for airborne and drone-borne repeat-pass #SAR #interferometry is the accurate knowledge of the flight trajectory. #GNSS errors are often comparable to radar wavelengths, especially at X-band and higher, making residual motion error (RME) estimation essential to achieve precise image coregistration and generate high-quality interferograms. 📊 Key contributions of our work: 1️⃣ We propose an enhanced version of the multisquint technique, solving RME estimation in the complex domain 2️⃣ The method refines motion estimates using the entire interferometric dataset, increasing robustness against large errors and decorrelation 3️⃣ Validation on a Ku-band drone-borne #SAR dataset demonstrates significant improvements in coregistration accuracy 4️⃣ Quantitative evaluations confirm the approach as a robust solution for high-precision interferometric applications 🌍 In short: this work helps bring drone-borne #SAR one step closer to delivering reliable, high-resolution #interferometric products, unlocking new opportunities for #EarthObservation at local scales. #SAR #DroneSAR #InSAR #RemoteSensing #EarthObservation #IEEE #TGRS #PolSAR #Innovation

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Today Geneva Ecola presented our work “SARLink: Satellite Backscatter Connectivity using Synthetic Aperture Radar” at ACM SenSys! In this paper we explore how we can use spaceborne SAR satellites not just to image Earth, but also enable passive wireless communication. We present a new approach to enabling satellite backscatter connectivity by modulating a corner reflector on the ground and present a data processing algorithm that utilizes subaperture processing to demonstrate that bits of information can be extracted from SAR images generated by Sentinel-1. Congrats to Geneva on a great presentation, and thanks to our amazing collaborators: Bill Yen, Anna B., Bodhi Priyantha, and Ranveer Chandra

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Over the past 12 years, the Stanford Space Rendezvous Laboratory has developed and deployed several #algorithms to perform provably #optimal #control of the #RelativeMotion between #satellites with computational performance superior to conventional #convex optimization. The key strategy has been to use #ReachableSetTheory as an indirect optimization method. This led to both closed-form solutions and to very efficient numerical techniques. For the first time at the 2025 AAS/AIAA Astrodynamics Specialist #Conference, Boston, Massachusetts, August 10-14 2025 (https://lnkd.in/dGs4-JD4), we are presenting the application of the methodology to the restricted three body problem. The paper titled: "Optimal Impulsive Control of Cislunar Relative Motion using Reachable Set Theory" by Matthew Hunter, Walter Manuel, and Simone D'Amico is available for download as draft: https://lnkd.in/d8E5m8vN This work presents the first application of the state-of-the-art Koenig-D’Amico reachable set theory solver to cislunar, chaotic relative motion in the CircularRestricted Three-Body Problem (CR3BP). The relative motion dynamics of two spacecraft, a chief and a deputy, in the CR3BP are formulated as a Linear TimeVariant (LTV) system, allowing the solver to find an optimal impulsive control maneuver plan. This methodology demonstrates robust and accurate control performance for both small and large reconfigurations over different CR3BP orbits and control windows. These capabilities are enhanced by a Model Predictive Control (MPC) architecture to reject all sources of control, navigation, and dynamic error. The performance of the proposed approach is validated by unit testing, Monte Carlo simulations, and comparisons to baseline models for spacecraft relative motion. Overall, this work demonstrates an optimal control methodology with the computational efficiency to be used on-board spacecraft, enabling the safe, effective, and efficient operation of Distributed Space Systems in cislunar space.

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New journal paper, “Space Logistics Analysis and Incentive Design for Commercialization of Orbital Debris Remediation”, on Journal of Spacecraft and Rockets. With #spacedebris posing a significant threat to the burgeoning space economy, the need for active remediation is more critical than ever. However, current studies often lack the detailed operational and economic analysis required to build a viable business case for commercial cleanup services. This paper, for the first time, develops a #spacelogistics framework to conduct a comprehensive analysis of active space debris remediation methods. By integrating a network-based logistics model (for space mission design and costs) with game theory (for bargaining), our research provides a quantitative basis for designing incentive mechanisms that foster mutually beneficial partnerships between space operators and debris remediators. These findings represent a significant step toward creating a safe, sustainable, and profitable commercial market for keeping our orbits clear. Many thanks to the support of NASA Office of Technology, Policy and Strategy (OTPS) on this project. Special recognition and thanks to my former Ph.D. student Dr. Asaad Abdul-Hamid, Ph.D. for an outstanding work as the first author, and to co-authors Brycen Pearl and Dr. Hang Woon Lee for their contributions. https://lnkd.in/e4P2rZXM #spaceconomy #sustainablespace

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Enabling Earth Observation: TI’s Role in ISRO-NASA’s NISAR Satellite #satellite Texas Instruments (TI) and SAC-ISRO collaborated on the technology behind the NISAR #satellite mission, now in orbit above Earth. As the world’s first dual-band synthetic aperture radar satellite, NISAR is designed to monitor ecosystems, natural disasters, and climate patterns. Mark Toth, who is in charge of marketing and applications for Space Power Products at TI, told Embedded.com that the company’s extensive selection of space-qualified ICs was vital for helping engineers satisfy the mission’s performance and #reliability criteria. #space #electronics Full Article: https://lnkd.in/g9Z5swA5

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Back to the fundamentals of radar geometry… Last week, one of my students showed me a figure about SAR geometry, which I… simply couldn’t interpret 😅 I couldn’t tell in which plane the cross-range axis was defined — or how it fit within the rest of the radar geometry. So I decided to revisit the 3D geometry of radar imaging, especially what happens when we move away from the classic broadside configuration toward a squinted geometry. To get my ideas straight, I wrote a small Python script to visualize in 3D: - the main planes of the local radar frame (ground plane, slant plane, incidence plane, image plane), - the radar look direction, - the platform trajectory, - and those elusive range and cross-range axes. From that little exercise came a new Medium article, where I explain step by step how the geometry of a squinted SAR image actually works — and why the cross-range axis is often misunderstood (and misnamed). 👉 The post includes the full Python code to explore SAR geometry interactively in 3D — a simple but powerful way to see what the equations describe. #student #SAR #radar #geometry #squint #3D

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