Synthetic Aperture Radar (SAR), despite being an active microwave imaging sensor, is not immune to RFI, which can significantly compromise the integrity and reliability of acquired data. At the same time, the increasing frequency and severity of natural disasters driven by climate change reinforce the need for continuous, accurate monitoring of the Earth’s dynamic environment. SAR plays a key role here thanks to its ability to operate regardless of weather or lighting conditions. 

In this context, the detection, characterisation, and mitigation of RFI have become critical to ensuring reliable SAR data for disaster prediction, monitoring, and damage assessment.

The approach: a modular RFI simulator

To address this need, we developed a modular software framework that simulates multiple types of RFI at raw data level and injects them into clean Sentinel-1 acquisitions. The simulator serves two purposes.

First, it provides a controlled environment to evaluate the performance of conventional detection and mitigation techniques, identify their limitations, and explore potential improvements.

Second, and equally important, it enables the generation of a synthetically contaminated and accurately labelled dataset, which is essential for training Deep Learning models. Reliable labels are notoriously hard to obtain when working with real-world RFI, and a high-fidelity simulator helps achieve good generalisation while reducing the risk of domain shift when these models are later applied to operational data.

What the project delivered

The thesis combines three contributions in a single framework: a modular implementation of multiple RFI types at raw processing level, a set of detection and mitigation algorithms integrated under a common evaluation framework that enables fair comparison, and a labelled dataset designed to train Deep Learning models capable of detecting RFI before SAR focusing, where mitigation is most effective.

Making it possible at Zenithal Blue

The purpose of a master’s thesis is to push into the borders of knowledge in a specific field. Thanks to Zenithal Blue, I was able to do exactly that: explore new directions for the company while laying the foundation of my own career, at least for the coming years through a PhD. The trust the company placed in me was the main reason I stayed motivated and felt capable of taking the project on.

For a master’s student taking the first steps into the space sector, collaborating with highly skilled professionals is an invaluable experience. Being part of a company involved in top-tier projects and feeling like a real contributor rather than an observer is something not every student gets to experience, and it has made all the difference.

La entrada Simulating radio frequency interference in Sentinel-1 at raw data level se publicó primero en Zenithal Blue.

That’s not true. And I say this from the experience of someone who has spent twenty years in research, who has moved in and out of both the academic world and the private one, and who today works at Zenithal Blue precisely because here he can keep being what he has been his whole life: a scientist.

A scientific vocation isn’t a profession. It’s a way of being

When I say I’m a vocational scientist, I don’t just mean that I work in science. I mean something deeper. University teaches you to think; it teaches you to apply the scientific method. But the vocation comes before that: it’s something you find in your life that defines who you are. For as long as I can remember, I’ve wanted to be a researcher. And even when you dedicate yourself to it professionally, once that vocation has been with you for a long time, you essentially shape your life and your way of thinking around it.

It’s a vocation similar to that of someone who decides to be religious, or who has an artistic or musical calling. You don’t entirely choose it. You recognize it.

Why Zenithal Blue

One of the reasons I enjoy working at Zenithal Blue is that the founder, Roger Oliva, supports a more academic vision of how to do things. We have PhD students, we host master’s theses, and we support academic development while pursuing scientific excellence. That’s not common in a private company, and it shouldn’t be taken for granted.

We work as scientists and engineers with innate curiosity. And we also benefit from a flexibility that other environments, especially public ones, can’t always offer. That combination, academic rigor with the agility of a company, is hard to find, and when you find it, it’s worth taking care of.

On the Earth observation community

There’s no university degree that certifies you as an “Earth observation scientist.” It’s a title that all of us impose on ourselves. Those who, from different disciplines and different countries, have decided to devote our careers to understanding the planet from space.

And within that community there’s something I find especially valuable: a high degree of internationalization, where people from very different cultures and countries find common ground in wanting to work together to address the great challenges. There’s a lot of unity around what the goals are, what we want to achieve, and why it matters.

New Space, satellite constellations, the democratization of access to space… none of that would have been possible without nearly 75 years of intense work, international collaboration, and knowledge transfer between institutions and companies. We’re inheriting an enormous legacy, and we have a responsibility to keep building on it.

What science in a company shouldn’t mean

Working in a company doesn’t mean abandoning rigor, nor that results are predetermined by whoever provides the funding, nor even that curiosity becomes subordinate to the commercial margin. In the best case, it means you can apply that rigor to real problems, with real resources, and with the possibility of seeing results that go further and faster than they would from a public institution with long, uncertain funding cycles.

That’s what I try to do. And it’s what, at Zenithal Blue, I have the freedom to do.

La entrada Being a vocational scientist in a private company se publicó primero en Zenithal Blue.

Our main client to date has been the European Space Agency (ESA), an organization with a clear scientific and industrial vocation and a well-defined goal: to transfer the knowledge generated in academia and specialized industry to a broader cross-section of society. That approach has worked so well that Europe is now home to some of the organizations with the deepest expertise in aerospace technology in the world.

Working in that environment forces you to think beyond the quarter. And that fits perfectly with who we are.

Small companies have something that can sometimes get diluted in large ones

Zenithal Blue is a relatively small company. And that’s an advantage in what matters most to us: the strength of conviction about what you do. In our case, we share that conviction as a team, which is the desire to work on projects that genuinely have an impact on society.

This isn’t an empty statement of intent. The kind of projects we seek out, and the ones we decide not to take on, prove it. We work on projects that provide vital information for better understanding the global climate and the impact of climate change. We work on the design of future missions to observe the Earth and solve problems that are critical for society. And we work on developing dual-use technologies to protect European interests and values.

These are areas of work that we actively pursue because we believe in them.

Economic profit is not the enemy of purpose

It’s important to make one thing clear: the pursuit of purpose isn’t incompatible with economic viability. Publicly traded companies have shareholders who expect a return on their investment, and that’s legitimate. But that doesn’t exhaust or define the full spirit and actions of a company, nor its purpose toward society.

At Zenithal Blue, economic sustainability is a necessary condition for being able to do the work we want to do. It isn’t the end goal. The end goal is impact.

A highly qualified team in service of what we believe matters

Every member of the team holds a very high level of academic qualification: PhDs and engineers, with experience accumulated across long-term projects. We put that experience in service of what we believe we can do best for society.

And in a sector as competitive and as oriented toward technical excellence as aerospace, that’s not a luxury. It’s a decision we make every time we choose a project.

La entrada A company with purpose: why we do science from within a startup se publicó primero en Zenithal Blue.

An idea that was born in 2018

The idea for this project was co-developed with the Institut de Ciències del Mar in Barcelona in 2018. The central question was whether it was possible to combine salinity and temperature measurements from satellite to measure variations in heat content in the upper layer of the ocean, and from there to better understand the physical processes of exchange between the two fluids: the ocean and the atmosphere.

In 2024 we submitted the proposal to ESA. In 2025 we were told we had won it. We have now been working on it for a year, and it has proven to be a very compelling project.

Why these exchanges matter so much

Since my university days I have been convinced that the interrelationships between heat exchanges between the atmosphere and the ocean — occurring at different times, at different scales and in different places — are behind many of the extreme climate events we are experiencing. And also behind the long-term scaling of climate variation: heatwaves, droughts, changes in the water cycle.

These phenomena represent very serious threats to a large part of the world’s population, even though we still do not seem to be placing enough emphasis on understanding their long-term consequences.

What makes this project special is that, for the first time, satellites are being used to systematically observe these exchanges at the ocean surface. It is a new use of already existing data, applied to a question that has gone without a sufficiently precise answer for decades.

The value of finding new uses for existing data

Much of what we do at Zenithal Blue is exactly this: discovering new uses for satellite data that is already available. A new satellite is not always needed to advance knowledge. Sometimes the answer lies in data we already have, waiting to be read in a different way.

At the same time, when we identify gaps in available information that cannot be resolved with current satellites, those gaps become the seed for the next generation of Earth observation missions. This is how the cycle works: exploit what exists, identify what is missing, propose what comes next.

The ocean as a climate regulation system

The ocean is not a passive backdrop against which things happen. It is an active system that absorbs, stores and redistributes heat on a global scale. Understanding how it does this — with what intensity, in which areas, and in response to what conditions — is fundamental to improving climate models and to better anticipating what lies ahead.

This is the kind of scientific question that, back in my university days, already struck me as essential. Being able to work on it now, with the resources and independence we have at Zenithal Blue, is precisely the kind of research that makes building this company worthwhile.

La entrada The ocean and the climate: why measuring heat exchange between the sea and the atmosphere matters se publicó primero en Zenithal Blue.