GNSS-RO Satellites as a Tool for Identifying GNSS Interference, Jamming, and Spoofing

Global Navigation Satellite Systems (GNSS) underpin everything from smartphone navigation to aviation safety and emergency response. As reliance on GNSS grows, so does the vulnerability of these signals to interference, both accidental and deliberate. In recent years, intentional disruption techniques such as jamming and spoofing have become more frequent and more sophisticated, creating a pressing need for reliable detection and monitoring tools.

One emerging and underutilized capability in this space is GNSS Radio Occultation (GNSS-RO) satellites. Traditionally used for atmospheric sounding, GNSS-RO satellites also offer an added benefit and unique vantage point for detecting interference at a global scale.

Understanding GNSS Interference

Interference affecting GNSS signals broadly falls into two categories:

Unintentional interference, such as radio frequency (RF) noise from TV station signals, electronic devices, etc
Intentional interference, which includes:
- Jamming: broadcasting noise to overwhelm GNSS signals and degrade or deny receiver performance
- Spoofing: transmitting counterfeit GNSS signals that imitate authentic ones to mislead receivers

As highlighted in prior research, GNSS has long been recognized as susceptible to interference, making it an attractive target for both cyber and electronic warfare actors [1]. These threats are no longer hypothetical, they are actively impacting real-world operations across aviation, maritime navigation, and critical infrastructure.

Recent reporting highlights how GPS interference is being used in modern conflict environments, affecting both civilian and military systems. For example, a CNN report on GPS disruption during the Iran conflict describes how commercial aircraft and ships experienced degraded navigation due to widespread jamming activity [2]. Similarly, coverage from RCR Wireless News details how jamming incidents are increasingly targeting critical sectors, including transportation and communications infrastructure [3].

Additional international reporting reinforces the scale of the issue. Analysis published by RTÉ explains how aviation systems are being directly affected by both jamming and spoofing [4], while High North News highlights the economic risks associated with satellite outages in northern regions [5]. Broader coverage aggregated by MSN further emphasizes that GPS jamming is becoming a widespread and increasingly normalized tool in modern electronic warfare [6].

Key takeaways from recent incidents include:

Increased frequency of GNSS interference in geopolitical conflict zones
Direct impacts on commercial aviation safety and maritime navigation
Growing risk to critical infrastructure and emergency services
Expanding use of jamming as a low-cost, high-impact warfare tactic

Why Detection Is Challenging

GNSS signals arriving at Earth are extremely weak, making them inherently difficult to protect. Detecting interference requires distinguishing between legitimate satellite transmissions and malicious or anomalous signals.

One approach explored in the literature is Radio Frequency Fingerprinting (RFF), a technique designed to identify unique characteristics of signal transmitters. Subtle hardware-specific features embedded in GNSS signals can, under high signal-to-noise conditions, enable identification of individual satellites or anomalous transmitters [7].

However, achieving this level of precision typically requires specialized equipment (e.g., high-gain antennas) and is often limited to localized or receiver-based applications.

Enter GNSS Radio Occultation (GNSS-RO) Satellites

GNSS-RO is a space-based remote sensing technique that measures how GNSS signals bend as they pass through Earth’s atmosphere. These measurements are widely used in weather forecasting and climate science.

But importantly, GNSS-RO satellites also capture signal amplitude and phase characteristics across a global network of satellites, creating an opportunity to detect anomalies that may indicate interference.

A Unique Detection Opportunity

Under normal conditions, GNSS-RO signals become extremely weak when the transmitting satellite is geometrically obscured by the Earth (deep occultation). At these points, signal levels approach background noise.

This creates a powerful detection mechanism:

Expected condition: near-zero signal amplitude
Anomalous condition: elevated signal amplitude → potential interference source

Using this principle, recent research has demonstrated that GNSS-RO data can be used to detect and monitor jamming activity over time and across large geographic regions [8].

Real-World Evidence from GNSS-RO

Analysis of GNSS-RO datasets, including data from missions like COSMIC-2 and PlaneiQ’s commercial constellation, has revealed measurable patterns of interference:

Persistent increases in signal anomalies over known conflict zones such as the Mediterranean, Middle East, and Central Africa
Long-term trends indicating growing jamming activity starting around 2017
Noticeable changes in interference patterns tied to geopolitical events

These findings highlight GNSS-RO’s ability not just to detect interference, but to track its evolution over time and geography, a capability that is difficult to achieve with ground-based systems alone [8].

Complementing Existing Countermeasures

Traditional approaches to GNSS interference mitigation include:

Signal processing techniques
Antenna array systems
Cryptographic authentication
Machine learning-based detection

These methods are typically implemented at the receiver level and focus on either detecting or mitigating interference locally [1].

GNSS-RO adds a complementary layer:

Global monitoring instead of local detection
Independent sensing from space-based platforms
Passive observation, requiring no modification to user equipment
High Signal-to-Noise (SNR) sensing techniques, like those deployed on PlanetiQ’s Pixis RO receiver, help with jamming and spoofing situational awareness and source geolocation

In combination with receiver-based techniques such as RFF, GNSS-RO can enable a more comprehensive and resilient interference detection architecture.

Implications for Aviation and Autonomous Systems

The stakes are particularly high in safety-critical applications. Aviation, including the rapidly growing use of unmanned aerial vehicles (UAVs), depends heavily on reliable GNSS signals.

Interference can degrade navigation accuracy or lead to complete signal loss, posing risks to:

Aircraft navigation and landing systems
Emergency response operations
Autonomous vehicle guidance

Robust detection capabilities are essential, not only to identify interference events, but to support timely mitigation and ensure operational safety [1][7].

Looking Ahead

GNSS interference is not going away; in fact, the evidence suggests it is increasing in both frequency and sophistication. Addressing this challenge will require layered solutions that combine:

Receiver-level intelligence (e.g., RFF and signal authentication)
System-level resilience (e.g., multi-sensor fusion)
Global monitoring capabilities like GNSS-RO

By leveraging its unique geometry and sensitivity to signal anomalies, GNSS-RO has the potential to play a critical role in identifying and characterizing interference worldwide.