Jamming and Spoofing: Differences and Impact
on GNSS Positioning
Shykie Zhong, Tersus GNSS 18 April, 2025
Introduction
Global Navigation Satellite Systems (GNSS), such as GPS, GLONASS, Galileo, and BeiDou, play a crucial role in modern navigation, timing, and positioning applications. However, GNSS signals are vulnerable to intentional and unintentional interference, with jamming and spoofing being the two primary threats. Understanding the differences between the two attacks and their effects on GNSS positioning is essential for developing effective countermeasures.
Jamming vs. Spoofing: Key Differences
1. Jamming
Jamming refers to the deliberate transmission of radio frequency (RF) noise or signals at the same frequency as GNSS signals to overpower and disrupt reception.
•Objective: Deny GNSS service by making the receiver unable to acquire or track satellite signals.
•Method: Emits high-power noise (e.g., white noise, swept tones) across GNSS frequency bands (L1, L2, L5).
•Impact: Causes a complete loss of positioning or degraded accuracy.
•Detection: Sudden loss of signal strength, increased noise floor, or failure to compute a position.
2. Spoofing
Spoofing is a more sophisticated attack where fake GNSS signals are broadcast to deceive a receiver into calculating an incorrect position or time.
•Objective: Mislead the GNSS receiver by providing false but believable signals.
•Method: Generates counterfeit satellite signals with manipulated timing and navigation data.
•Impact: The receiver computes a wrong position or time without realizing it is under attack.
•Detection: Difficult to detect without advanced anti-spoofing techniques (e.g., signal authentication, consistency checks).
Effects on GNSS Positioning
1. Impact of Jamming
•Complete Signal Loss: In strong jamming scenarios, the GNSS receiver may lose all signals, leading to a total positioning failure.
•Degraded Accuracy:Weak jamming increases noise, reducing signal-to-noise ratio (SNR) and causing position drift.
•Application Disruptions:Affects critical systems like aviation, maritime navigation, and military operations.
2. Impact of Spoofing
•False Position Fixing:The receiver may display a manipulated position, leading to navigation errors (e.g., misleading a drone or ship).
•Time Spoofing:GNSS is widely used for time synchronization (e.g., in power grids, financial systems). Spoofing can cause severe timing errors.
•Security Risks:Spoofing can be used in military deception, drone hijacking, or autonomous vehicle sabotage.
Mitigation Strategies
1. Anti-Jamming Techniques
•Adaptive Filtering: Use of notch filters to suppress jamming frequencies.
•Beamforming Antennas: Directional antennas (e.g., Controlled Reception Pattern Antennas - CRPAs) to nullify jammers.
•Inertial Navigation Systems (INS): Integration with INS provides backup positioning during GNSS outages.
2 Anti-Spoofing Techniques
•Signal Authentication:Galileo’s Open Service Navigation Message Authentication (OSNMA) ensures signal legitimacy.
•Multi-Frequency & Multi-Constellation:Using multiple GNSS bands (L1, L5) and systems (GPS + Galileo) makes spoofing harder.
•Receiver-Level Detection:Monitoring signal strength, Doppler shifts, and consistency checks to identify anomalies.
Conclusion
While both jamming and spoofing pose significant threats to GNSS reliability, they differ in methodology and impact. Jamming disrupts service outright, whereas spoofing deceives the receiver subtly. Mitigation requires a combination of advanced signal processing, multi-system redundancy, and authentication mechanisms. As GNSS applications expand, developing robust anti-jamming and anti-spoofing solutions remains critical for ensuring secure and resilient positioning.
About Tersus GNSS Inc.
Tersus GNSS is a leading Global Navigation Satellite System (GNSS) solution provider. Our offerings and services aim to make centimeter-precision positioning affordable for large-scale deployment.
Founded in 2014, we have been pioneers in design and development GNSS RTK products to better cater to the industry’s needs. Our portfolios cover GNSS RTK & PPK OEM boards, David GNSS Receiver, Oscar GNSS Receiver, MatrixRTK [GNSS CORS Systems] and inertial navigation systems.
Designed for ease of use, our solutions support multi-GNSS and provide flexible interfaces for a variety of applications, such as UAVs, surveying, mapping, precision agriculture, lane-level navigation, construction engineering, and deformation monitoring.
Sales inquiry: sales@tersus-gnss.com
Technical support: support@tersus-gnss.com