Anti-Jamming and Anti-Spoofing Technologies Safeguard Flight Safety

In today’s world, where UAV and manned aviation flight safety is paramount, GNSS jamming and spoofing have become hidden yet severe threats. To ensure the absolute safety of every flight, it is essential to build inherent protection capabilities at the very core of the navigation system—the receiver level. Through deep integration of multi-frequency GNSS technology, intelligent heuristic algorithms, and satellite signal encryption/authentication, Septentrio can distinguish genuine from fake signals at the source in real-time, resist interference, and provide accurate, reliable security alerts when spoofing occurs. With twenty years of technical expertise, Septentrio seamlessly integrates anti-jamming and anti-spoofing capabilities, requiring no additional complex hardware to imbue aircraft with inherent resilience. Choosing comprehensive protection from the core to the system means choosing an uncompromising commitment to safety—ensuring every journey commences and concludes safely within trusted spatiotemporal coordinates.

Analysis of GNSS Jamming and Spoofing

About Jamming

Jamming is a signal disruptor in the field of GNSS navigation. It emits powerful radio noise, acting like an invisible barrier that directly drowns out the weak signals from satellites. When jamming occurs, the receiver does not see an erroneous position but rather a complete loss of signal—the positioning icon freezes, time information is lost, and navigation functions are completely interrupted. Whether caused by unintentional electromagnetic interference or deliberate suppression attacks, the essence of jamming is the violent suppression of signals. Its disruption is direct and rapid, capable of instantly “blinding” systems reliant on GNSS. This attack method is common in military confrontations, privacy protection scenarios, and even frequently appears in civilian areas such as logistics fleets and examination venues due to the misuse of cheap jammers.

About Spoofing

Spoofing, on the other hand, is a master of deception in the GNSS domain. It does not disrupt signals but meticulously forges a set of “cloned” signals almost identical to genuine satellite signals, stealthily “injecting” them into the receiver. The receiver decodes and calculates these fake signals as if they were real, ultimately outputting information—position, velocity, or time—that appears completely normal but is actually entirely wrong. More dangerously, advanced spoofing can achieve gradual “slow-burn” manipulation, causing the target to deviate from its course unknowingly. This attack is highly covert and harmful, ranging from luring autonomous vehicles into traps and hijacking cargo drones to tampering with financial system timestamps. Its essence is a precise betrayal of trust, aiming not to make you “lose your way” but to make you “take a wrong path.”

Spoofing often accompanies jamming. Jamming suppresses GNSS signals with “white noise” to disable them. It breaks the receiver’s lock on GNSS signals, making the receiver more likely to lock onto false signals. Jamming other signals during a spoofing attack eliminates the receiver’s possibility of falling back to other signals. Therefore, the first line of defense against spoofing is built-in robust anti-jamming technology in the receiver, such as AIM+ Advanced Interference Mitigation.

Different Forms of Spoofing

Elementary Imitation – Non-Coherent Attack

Non-coherent attacks are the most basic form of spoofing, akin to creating a crudely forged painting. The attacker uses inexpensive software-defined radio (SDR) equipment and open-source software to directly transmit forged signals with power far stronger than genuine satellite signals. This attack is often accompanied by brief jamming, first breaking the receiver’s original signal lock and then “violently taking over” with stronger fake signals. Although the implementation barrier is low, with costs under a thousand dollars, its flaws are also most apparent—the signals lack precise synchronization, exhibit abnormal power characteristics, and positioning results often show abrupt jumps. Such attacks are common in scenarios like personal device hijacking and location spoofing, representing the most prevalent spoofing threat today.

Precise Camouflage – Coherent Attack

Coherent attacks represent an intermediate form of spoofing technology, comparable to meticulously crafted high-quality forgeries. The attacker uses professional-grade GNSS simulators, first synchronizing the forged signals with genuine satellite signals in time and phase, and then gradually and imperceptibly “pulling away” the receiver’s tracking loops at a slow pace. The entire process is smooth and covert, not triggering traditional jump alarms, causing the target system to deviate from the correct trajectory unknowingly. This “slow-burn” type of attack requires professional knowledge and investment in equipment worth tens of thousands of dollars or more. However, its strong concealment makes it effective against basic detection methods, often used for high-value target attacks such as high-end UAV hijacking or secret modification of ship routes.

Perfect Replication – Meaconing Attack

Meaconing (signal rebroadcast) attacks are a special advanced form of spoofing technology. They do not “forge” but “replicate” genuine signals, akin to creating an exact replica displayed separately from the original. The attacker receives genuine satellite signals, rebroadcasts them after a short delay, causing the receiver to calculate an erroneous position (re-broadcast antenna location + delay error). Most dangerously, since the rebroadcast signal content is completely genuine, conventional code pattern analysis and message validation cannot identify this attack. This technique may be used in specialized fields such as military deception or equipment testing, but can also cause unintentional regional interference due to accidental leakage of test signals. It is the most challenging to detect and defend against among the three types of spoofing.

Types of Interference Protected by AIM+ (Adaptive Interference Mitigation Software+)

Spurious Peaks from Radio Amateurs and Digital TV

Non-malicious signal-emitting devices (e.g., amateur radio stations, TV transmitters) may generate unintended strong signal peaks (spurious emissions) outside their operating bands due to design flaws or malfunctions. These strong peaks can overwhelm weak satellite navigation signals, causing receiver loss of lock. The built-in AIM+ advanced anti-jamming and anti-spoofing technology in the Mosaic P3H provides robust navigation signal security for PX4 systems.

Signals from Inmarsat and Iridium Satellite Systems

The frequency bands used by Inmarsat and Iridium satellite systems are adjacent to or partially overlap with GNSS bands. Their powerful downlink signals can cause out-of-band blocking interference or adjacent-channel interference to nearby GNSS receivers.

DME (Distance Measuring Equipment) Pulse Interference Around Airports

DME is an aeronautical navigation device operating in the 960-1215 MHz band, overlapping with the GPS L5 band. The high-power pulse pairs it emits severely interfere with satellite signals. This can cause frequent satellite loss and unreliable positioning for receivers near airports. Septentrio mosaic-G5 supports RTK high-precision positioning mode, enabling PX4 to achieve centimeter-level autonomous flight and precise operations.

Wideband Interference from “Chirp” Jammers

“Chirp” jammers are a common type of malicious jamming device. They rapidly and periodically scan a wide frequency band (e.g., the entire GNSS band), generating powerful, transient interference covering the full band. Traditional static filters struggle to cope, effectively paralyzing most commercial receivers.

Septentrio Solutions

Core Protection Philosophy: Endogenous, Multi-Layered, Full-Stack

Septentrio’s protection philosophy emphasizes that “spoofing protection capability begins at the receiver core,” opposing post-hoc remedial “patchwork” solutions. Its core tenet is that the most efficient and cost-effective protection must be built into the receiver chip and firmware level, constructing native resilience at the very front end of signal processing. This philosophy permeates its entire solution system.

Four-in-One Core Technology System

Septentrio has built a four-layer collaborative protection system from the signal reception source to the system application layer:

Multi-Frequency/Multi-Constellation Technology

Principle: Simultaneously receives and processes signals from multiple frequency bands (e.g., GPS L1/L2/L5, Galileo E1/E5) and multiple satellite systems.

Role: Forces attackers to simultaneously and consistently forge signals across all frequency bands, greatly increasing the technical difficulty and cost of spoofing. It also provides rich signal redundancy; when some signals are under attack, it can automatically fall back to other healthy signals, ensuring continuous and reliable positioning.

Advanced Heuristic Algorithms

Principle: Develops proprietary intelligent algorithms based on massive data accumulated from over 20 years of field operation, continuously monitoring hundreds of signal parameters (power, timing, consistency, etc.) to detect the subtlest abnormal patterns.

Role: Acts like an experienced art authenticator, effectively detecting complex spoofing, including covert “pull-off” attacks. The algorithms can set precise thresholds, generate “true and trustworthy spoofing flags,” minimizing false positives and false negatives, providing accurate threat alerts to upper-layer systems.

Cryptographic Authentication Support

Principle: Supports and integrates future satellite signal authentication services, such as Galileo’s OSNMA and GPS’s Chimera. Verifies the digital signatures from satellites to confirm signal authenticity at the source.

Role: Provides a theoretically fundamental anti-spoofing method, adding a layer of cryptography-based trust anchor to the system.

System-Level Sensor Fusion Interface

Principle: Designs open interfaces for the receiver to facilitate deep integration and data comparison with other navigation sources like Inertial Measurement Units (IMU), visual sensors, and LiDAR.

Role: Adds a cross-sensor verification layer on top of the receiver’s internal protection, building deeper defense, especially suitable for high-safety-requirement scenarios like autonomous driving.

AIM+ (Advanced Interference Mitigation and Anti-Spoofing) Technology

The aforementioned multi-layer technologies are integrated into its core product, AIM+ (Advanced Interference Mitigation and Anti-Spoofing) Technology:

-Anti-Jamming First: Recognizing that “jamming often accompanies spoofing,” AIM+ first possesses robust anti-wideband and narrowband jamming capabilities, ensuring the receiver maintains lock on genuine signals in complex electromagnetic environments. This is the first solid line of defense against spoofing.

-Deep Hardware-Software Integration: As a built-in technology, AIM+ requires no additional hardware, calibration, or special antennas, reducing system complexity, cost, and integration difficulty while avoiding potential side effects like latency from external devices.

-Comprehensive Response: Can simultaneously utilize multi-frequency detection, heuristic algorithms, and cryptographic information for real-time detection and mitigation of various spoofing attacks, from simple to complex.

Summary of Core Solution Advantages

-Resilience from Core to System: Protection begins at the receiver chip level, ensuring the foundation of the entire positioning system is solid.

-Validated by Twenty Years of Experience: Algorithms and thresholds are trained based on long-term real-world operational data, not just laboratory theory, ensuring high reliability.

-High-Accuracy Threat Awareness: Capable of generating accurate spoofing flags, avoiding safety risks caused by false positives (disrupting the system) or false negatives (missing attacks).

-Optimal Cost-Effectiveness: Built-in design avoids expensive additional hardware, providing the highest cost-performance system-level protection.

-Future-Oriented: Proactively supports next-generation security standards like satellite signal authentication, protecting customers’ long-term investment.

Conclusion

In the era of booming UAV and manned aircraft development, flight safety has become a non-negotiable bottom line. However, invisible radio waves harbor real threats—GNSS jamming and spoofing attacks are becoming increasingly common and sophisticated. From simple signal suppression to meticulously designed “pull-off” attacks, these threats are sufficient to misdirect navigation, disrupt formations, or even cause catastrophic consequences. In the face of these challenges, passive protection is no longer sufficient. True safety begins at the core of perception. As advocated by Septentrio, “protection capability begins at the receiver core,” we firmly believe that advanced multi-frequency GNSS technology, intelligent heuristic algorithms, and satellite signal encryption/authentication (e.g., OSNMA) must be deeply integrated into the receiver chip and firmware. This built-in, multi-layered protection system can distinguish genuine from fake signals at the signal level in real-time, lock onto genuine signals amidst interference, provide trustworthy alert flags when spoofing occurs, and ensure flight control systems always make decisions based on authentic and reliable position and time information.

Why is it said that “the first line of defense against spoofing is robust anti-jamming capability”? How does AIM+ technology reflect this?

Because spoofing attacks often occur alongside jamming. Jamming first suppresses genuine GNSS signals with noise, causing the receiver to lose lock and become more susceptible to takeover by false signals. If the receiver itself has weak anti-jamming capability, it will be unable to hold onto genuine signals during a spoofing event and will also lose the possibility of falling back to other healthy signals.

AIM+ technology fully embodies the principle of “anti-jamming first.” It features built-in powerful anti-wideband and narrowband jamming capabilities, effectively resisting various interferences from “chirp” jammers, DME pulses, adjacent-band systems, etc., ensuring the receiver maintains lock on genuine signals in complex electromagnetic environments. This lays a solid foundation for subsequent spoofing detection and mitigation, constituting a robust first line of defense against spoofing.

Which application scenarios are most vulnerable to spoofing attacks?

UAVs/Drones: Can be lured into no-fly zones or misled to specific landing points via spoofing, causing crashes or theft.

Maritime Navigation: Spoofing a ship’s AIS system can lead to deviation, collisions, or cover for smuggling.

Data Centers & Financial Systems: Rely on GNSS for high-precision timing. Spoofing can cause network outages or errors in financial transaction timestamps, leading to system chaos and economic risks.

Autonomous Vehicles: Spoofing can cause sudden deceleration or lane deviation, leading to traffic accidents.

Spoofing attacks often accompany jamming. Why is it said that “anti-jamming is the first line of defense against spoofing”? What synergistic relationship exists between the two?

Because jamming typically precedes or accompanies spoofing attacks. Its role is to suppress genuine GNSS signals, causing the receiver to lose lock on them. Once the receiver loses lock due to jamming, it becomes more susceptible to takeover by subsequently injected false signals. If jamming is implemented simultaneously during a spoofing attack, the receiver will be unable to fall back to other available signals, thus falling completely under the spoofer’s control. Therefore, built-in robust anti-jamming technology (like AIM+ Advanced Interference Mitigation) is foundational to ensuring the receiver maintains signal lock in complex electromagnetic environments, thereby enabling effective detection and resistance against spoofing attacks.