GPS satellite being manipulated by a shadowy figure, symbolizing GNSS spoofing.

Is Your GPS Safe? How to Spot and Stop GNSS Spoofing Attacks

Rhea Morgan in Tech & Innovation December 2025 • 4 min read.

"A simple guide to understanding and defending against GNSS spoofing with field-recorded data techniques."

In our increasingly connected world, Global Navigation Satellite Systems (GNSS) have become integral to various applications, from navigation apps on our smartphones to critical infrastructure management. This widespread reliance, however, makes GNSS vulnerable to malicious attacks, particularly spoofing. Spoofing involves transmitting false signals to mislead GNSS receivers about their location, time, or both. This poses significant risks to industries reliant on accurate positioning data.

The threat of GNSS spoofing is not merely theoretical. Successful spoofing attacks can disrupt transportation systems, compromise financial transactions, and even endanger lives. For instance, a manipulated GPS signal could reroute autonomous vehicles, leading to accidents. As such, understanding the mechanisms and countermeasures against GNSS spoofing is crucial for professionals and everyday users.

While sophisticated spoofing techniques are often studied in controlled, simulated environments, a recent study published in MethodsX offers a practical approach to generating realistic spoofing data. This method leverages field-recorded signals and cost-effective technology to analyze vulnerabilities and develop robust defenses against potential attacks. This article breaks down this innovative approach, making it accessible to readers seeking to protect their GNSS-dependent systems.

Understanding GNSS Spoofing: How Does It Work?

GPS satellite being manipulated by a shadowy figure, symbolizing GNSS spoofing.

GNSS spoofing attacks hinge on exploiting the relatively weak signals broadcast by satellites. By transmitting stronger, yet fabricated, signals, an attacker can gradually steer a victim's receiver towards an incorrect position or time. This manipulation often occurs in distinct phases, each designed to subtly undermine the receiver's integrity without raising immediate alarms.

The MethodsX paper details a method that simulates these real-world conditions by simultaneously recording GNSS signals with two separate receivers. One receiver represents the 'victim' under attack, while the other mimics the 'spoofer,' generating deceptive signals. By merging and analyzing these recordings, researchers can create realistic spoofing scenarios and test various detection methods.

Alignment Phase: The spoofer estimates the user's current state without transmitting any interfering signal.
Control Phase: The spoofer gradually increases its signal power, subtly nudging the target receiver to lock onto the false signal instead of the authentic one.
Pull-Off Phase: The spoofer slowly manipulates the receiver's reported position or time, guiding it towards the attacker's desired incorrect location.
Capture Phase: The spoofer has complete control over the target receiver, allowing it to feed completely fabricated data without the user realizing it.

This approach is significant because it incorporates real-world disturbances and environmental factors that are often difficult to replicate in simulations. As a result, the generated spoofing data is more authentic, providing a better foundation for developing effective anti-spoofing techniques.

Protecting Your Systems: How to Detect and Prevent GNSS Spoofing

While the MethodsX paper focuses on generating spoofing data for analysis, its insights can inform practical strategies for detecting and preventing attacks. By understanding the subtle manipulations that occur during a spoofing attempt, users and developers can implement more robust security measures. One of the methods is analyzing the signal patterns of the GNSS. This is achieved through ACF plots, which can detect multiple peaks indicating a spoofing attempt. Also, shape distortion of the signals can be used to detect spoofing.

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Everything You Need To Know

What exactly is GNSS spoofing, and why should I be concerned about it?

GNSS spoofing is a type of attack where false signals are transmitted to a Global Navigation Satellite System (GNSS) receiver. The goal is to mislead the receiver about its location, time, or both. This is important because many systems, from smartphone navigation to critical infrastructure, rely on GNSS for accurate positioning. Successful spoofing can disrupt transportation, compromise financial transactions, and endanger lives by providing incorrect location data. The implications of GNSS spoofing are far-reaching, potentially affecting any system dependent on accurate GNSS data.

Can you walk me through how a GNSS spoofer actually takes control of a receiver?

A GNSS spoofer manipulates the receiver in distinct phases. First in the Alignment Phase, the spoofer estimates the user's state. Then during the Control Phase, the spoofer gradually increases its signal power to get the target receiver to lock onto the false signal. After that, in the Pull-Off Phase, the spoofer slowly manipulates the receiver's reported position or time. Finally, in the Capture Phase, the spoofer has complete control. By understanding these phases, security measures can be developed to detect and prevent attacks. This includes looking at the real-world disturbances and environmental factors that are incorporated during an attack.

What is the significance of the MethodsX paper, and how does it help in understanding spoofing attacks?

The MethodsX paper offers a practical approach to generating realistic spoofing data. This is achieved by leveraging field-recorded signals and cost-effective technology to analyze vulnerabilities. By recording GNSS signals with two separate receivers, one mimicking the 'victim' and the other the 'spoofer,' researchers can merge and analyze these recordings to create realistic spoofing scenarios. This method is significant because it incorporates real-world disturbances that are often difficult to replicate in simulations. The generated spoofing data is more authentic, providing a better foundation for developing effective anti-spoofing techniques.

Besides the MethodsX paper, are there practical ways to detect and prevent GNSS spoofing?

Signal pattern analysis helps in detecting and preventing GNSS spoofing attacks. This can be done using methods such as ACF plots to detect multiple peaks, indicating a spoofing attempt. Shape distortion of the signals can also be used to detect spoofing. While other methods exist, signal pattern analysis offers a viable way to identify potential spoofing attempts by understanding subtle manipulations during the phases of a spoofing attack.

What are the different stages of a GNSS spoofing attack, and what happens during each one?

The four phases of a GNSS spoofing attack are the Alignment Phase, Control Phase, Pull-Off Phase, and Capture Phase. During the Alignment Phase, the spoofer estimates the user's current state without interference. In the Control Phase, the spoofer increases its signal power to lock the receiver onto the false signal. The Pull-Off Phase involves slowly manipulating the receiver's reported position or time. Finally, the Capture Phase gives the spoofer complete control over the receiver's data. Awareness of these phases is crucial for implementing effective countermeasures and detecting anomalies that indicate a spoofing attempt.