Why Satellite Spectrum Monitoring Is Becoming Essential in the Multi-Orbit Era

The rapid expansion of non-geostationary satellite constellations is transforming global communications, bringing new capabilities and connectivity to markets around the world. But as thousands of satellites operate across increasingly crowded frequency bands, ensuring that different networks can coexist without harmful interference is becoming a more complicated challenge.

For decades, satellite operators and regulators have relied on international coordination procedures and technical models to manage interference between geostationary and non-geostationary (NGSO) systems. Those frameworks remain essential, but the scale and complexity of today’s satellite networks are raising questions about whether theoretical calculations alone provide a sufficiently complete picture of what is happening in orbit.

At the International Telecommunication Union’s (ITU) Space Sustainability Forum in 2026, Emmanuel Houdet, director of mission solutions at Kratos, raised a fundamental concern: The satellite industry is developing increasingly sophisticated rules for interference protection without necessarily having enough real-world measurements to understand how well different networks are operating alongside one another.

That concern is shared, in part, by international regulators. Jorge Ciccorossi, head of the Space Strategy and Sustainability Division in the ITU Radiocommunication Bureau, emphasized the growing pressure on both orbital and spectrum resources as satellite deployments accelerate.

“Thousands of new satellites operating in similar altitude ranges and using overlapping frequency bands increase the complexity of avoiding harmful radio-frequency interference,” Ciccorossi told Constellations.

The challenge extends beyond protecting established GSO services. It increasingly involves managing spectrum among multiple NGSO constellations whose transmissions may overlap. As satellite networks grow, monitoring may need to become as important to responsible operations as the regulations governing spectrum sharing.

A New Era of Interference Complexity

Traditional GSO satellites operate from fixed positions relative to Earth, making their transmissions comparatively predictable. NGSO satellites, by contrast, move continuously across the sky, with changing positions, transmission paths and relationships to other satellites and ground stations.

The growth of large low Earth orbit constellations adds another layer of complexity. Modern systems use multiple beams, extensive frequency reuse and dynamic network configurations to deliver capacity across wide geographic areas.

These capabilities improve network performance but also complicate interference management, particularly when multiple NGSO constellations share frequencies with established GSO networks or with one another.

Houdet noted that coordination between increasingly large NGSO constellations and GEO satellites still depends heavily on rules developed before today’s megaconstellations were envisioned. He pointed specifically to equivalent power flux density (EPFD), a regulatory framework established through the ITU to protect certain GSO satellite services from interference generated by NGSO systems.

The framework dates to the late 1990s and early 2000s, when satellite architectures and operating environments were substantially different. At that time, Houdet suggested, the industry could not fully anticipate the scale of the interference-management challenge emerging today.

Recent academic research underscores the complexity. In a September 2026 paper titled Spectrum Sharing Among Broadband LEO Mega-Constellations: Interference Regulations and Coexistence Mechanisms, UCLA researcher Ian P. Roberts examined how multiple broadband constellations operating in overlapping Ku-, Ka- and Q/V-band spectrum face growing coordination challenges. The research highlights the potential for interference between competing NGSO networks, including cases where satellite user links and gateway transmissions occupy overlapping frequencies. As more constellations enter service, coordinating spectrum use becomes increasingly difficult.

When Regulatory Models Meet Operational Reality

EPFD is designed to evaluate the combined interference effect of transmissions from an NGSO system on a protected GSO receiving system, accounting for factors such as satellite positions, transmission power and antenna characteristics.

In practical terms, interference can increase the effective noise experienced by a receiving system, reducing the signal-to-noise ratio and potentially degrading communications performance. The ITU’s Article 22 EPFD limits provide a common technical framework for protecting GSO networks while allowing NGSO systems to share certain frequency bands.

Ciccorossi explained that the ITU Radio Regulations, an international treaty governing the use of spectrum and orbital resources, establish the foundation for interference protection among the organization’s 194 Member States. The framework incorporates frequency allocations under Article 5, EPFD limits under Article 22, coordination procedures under Article 9 and notification requirements under Article 11, along with other technical provisions.

These measures are intended to keep interference within acceptable limits while supporting the operation of different satellite services. But Houdet identified an important limitation.

“This works in theory,” he said, explaining that EPFD is a calculated regulatory measure rather than something that can be observed directly in its entirety. These models allow regulators and operators to evaluate proposed networks, assess compliance with applicable requirements and establish common expectations before systems begin operating.

However, simulated results depend on assumptions about satellite behavior, antenna performance, transmission characteristics and other variables. Actual operations introduce additional considerations, including changing satellite geometries, network configurations and the combined effects of multiple systems transmitting within shared spectrum.

This creates a distinction between evaluating compliance through established engineering methods and observing what is happening in the operating environment. Spectrum measurements do not automatically establish whether an operator has violated EPFD limits. The regulatory metric involves calculations and statistical conditions that cannot be replaced by an isolated measurement. Monitoring can provide evidence that helps explain interference events, validate operational assumptions and determine whether further investigation is warranted.

Why Monitoring Matters

Spectrum monitoring provides another dimension to interference management by allowing operators and regulators to observe actual satellite transmissions and investigate unexpected activity. For GSO operators, monitoring can help identify changes in received signal conditions, distinguish potential interference from equipment problems and collect technical evidence when service quality deteriorates. For NGSO operators, it can support the investigation of interactions with other networks and provide information useful for adjusting operating practices or coordinating with affected parties.

Regulators can use monitoring data to investigate complaints, assess observed emissions and support discussions between operators whose systems may be affecting one another. Ciccorossi emphasized that monitoring complements the ITU’s regulatory and technical framework.

“When it comes to satellite operations, spectrum monitoring is the key instrument to assess the actual situation and find solutions for interference mitigation,” he said. “In other words, if you cannot measure it, you cannot manage it.”

He also noted that monitoring helps operators verify that transmitted carriers correspond to authorized frequency assignments recorded in the ITU’s Master International Frequency Register.

By providing objective evidence of actual spectrum use, monitoring can support responsible operations, help resolve harmful interference and protect other satellite services.

Houdet, however, described monitoring as an underused source of information in discussions about GSO and NGSO coexistence. “Nearly nobody is doing measurements,” he said, referring to the limited real-world monitoring activity he had encountered in this area.

He described how observations can quickly reveal interactions that might otherwise remain poorly understood. “I start doing some measurements and immediately I see problems,” he said, citing interference observations involving Starlink and OneWeb transmissions.

Such observations do not, by themselves, establish harmful interference or regulatory violations. They illustrate the value of having observational data available to examine how satellite systems interact in practice.

The UCLA research provides an additional perspective on how monitoring could become more useful. Roberts examined how passive ground-based sensors could observe satellite transmissions to identify spectrum occupancy and beam activity without requiring access to user traffic. By combining these observations with orbital information, operators could potentially anticipate interference and adjust satellite assignments or transmission patterns before conflicts occur.

The research also suggests that ground-based measurements could help regulators evaluate actual satellite behavior, supplementing the simulations traditionally used during licensing. Although these approaches remain areas of ongoing research, they point toward monitoring becoming a more proactive tool for managing interference rather than simply documenting problems after they occur.

The Challenge of Monitoring Moving Targets

Monitoring NGSO constellations is considerably more complicated than observing relatively stationary GSO satellites. A monitoring system must account for satellites constantly changing position, multiple simultaneous transmissions, moving spot beams and varying signal conditions.

The UCLA research illustrates how quickly these conditions can change. Modern LEO networks dynamically steer beams across ground coverage areas and periodically transfer connections between satellites. The paper cites observations of satellite handovers occurring approximately every 15 seconds.

Interference can become particularly difficult to manage when satellites from competing constellations move into close angular alignment from the perspective of a ground receiver. In these circumstances, even highly directional antennas may struggle to distinguish desired transmissions from interfering signals.

The problem becomes more difficult when three or more constellations share overlapping frequencies. Techniques such as dividing spectrum between operators, adjusting beam patterns or selecting alternative satellites can become less effective as the number of competing systems increases.

Meaningful monitoring therefore involves more than detecting an unexpected signal. It requires understanding the operating context in which that signal was observed. That may involve correlating measurements with satellite orbital data, transmission characteristics and the timing of network activity. As satellite networks become more dynamic, the ability to interpret that information could become increasingly important to maintaining reliable services.

The Regulatory Framework Faces New Questions

The expansion of NGSO services is prompting renewed examination of international spectrum-sharing rules. The ITU’s EPFD framework provides an established basis for interference protection, but regulators are considering whether it should evolve to reflect advances in satellite technology and the changing scale of NGSO operations.

UK regulator Ofcom has proposed reforms to the international EPFD framework, seeking to improve spectrum-sharing efficiency while maintaining appropriate protection for GSO networks.

The debate reflects a difficult balance. Regulations must protect existing satellite services without unnecessarily restricting new systems that may deliver significant connectivity benefits.

Houdet compared interference rules to highway speed limits: A common standard helps establish expectations for everyone using the same environment. But establishing the rules is only part of the challenge. Operators and regulators also need a reliable understanding of actual system behavior. He questioned whether approaches that place greater responsibility on GSO operators to identify interference problems could create difficulties, particularly when coordination depends on operators exchanging technical information and resolving disputes directly.

Ciccorossi emphasized that international coordination remains central to maintaining compatibility between satellite systems. The ITU framework combines technical interference limits with procedures governing frequency assignments, coordination and notification. Monitoring adds an operational dimension to that framework by helping operators verify transmissions and investigate potential interference.

As constellations increasingly operate across national boundaries, those differences can complicate network planning and interference management. These questions are particularly relevant as the industry prepares for the 2027 World Radiocommunication Conference (WRC-27), where satellite spectrum-sharing issues remain part of the broader international regulatory discussion.

Toward More Automated Spectrum Coordination

Looking ahead, the challenge may extend beyond improving monitoring capabilities to developing new ways for satellite operators to coordinate their networks. The UCLA research examines whether approaches used for orbital collision avoidance could provide a model for more automated spectrum coordination.

Under such an approach, operators could potentially exchange information about satellite positions, coverage areas and planned operations to identify upcoming interference conditions.

Centralized information registries or direct coordination interfaces could help operators anticipate conflicts and adjust satellite assignments or transmission characteristics before harmful interference occurs.

However, these approaches would introduce their own complications, including protecting commercially sensitive operational data and determining which operator should modify its transmissions when competing systems have comparable spectrum rights.

For now, they remain potential approaches rather than established industry practices.

Nevertheless, they suggest that spectrum management may increasingly depend on combining regulatory models, real-world monitoring and more dynamic coordination mechanisms.

Monitoring as Part of Space Sustainability

Space sustainability is often associated with orbital debris, collision avoidance and responsible spacecraft disposal. But the reliable and equitable use of radio spectrum is another essential component of sustainable satellite operations.

Unlike physical orbital congestion, radio-frequency interference is not always visible or persistent. Yet its consequences can be significant when it affects communications, navigation or other services that depend on reliable satellite links.

As the industry moves toward increasingly interconnected, multi-orbit architectures, effective spectrum sharing will become more important to both commercial and government operations.

International regulations will remain central to that effort. But monitoring can complement those frameworks by providing evidence of actual operating conditions, supporting technical investigations and informing future policy discussions.

Ciccorossi described monitoring as an important contributor to “more efficient, reliable and sustainable use of increasingly congested spectrum-orbit resources.” It can also help establish a shared factual basis when operators disagree about the causes or effects of interference.

The challenge is not to replace models and coordination procedures with measurements, but to combine them more effectively. The UCLA research reinforces that direction, suggesting that passive monitoring, predictive analysis and improved coordination could help operators manage interference in environments involving multiple large constellations.

For Houdet, the central issue is straightforward: Before the industry can determine whether its rules adequately address today’s satellite environment, it needs a clearer understanding of what is happening in the sky.

As GSO and NGSO networks continue to expand, that distinction between predicted interference and observed operations may become one of the defining issues in satellite spectrum management. The future of sustainable satellite communications will depend not only on establishing effective rules for sharing spectrum, but also on understanding how well those rules work in practice.