A joint report by Sweden and five neighboring countries warns that nearly 123,000 flights were disrupted between January and April by Russian jamming and spoofing of satellite navigation systems, according to EU Today. The countries submitted their report to the International Civil Aviation Organization (ICAO).
The disruptions were traced to Kaliningrad, St. Petersburg, Smolensk and Rostov. They affected flights operated by 365 airlines over Poland, the Baltics, Finland and Sweden. In April, more than 27% of flights in the region experienced interference, with some areas experiencing rates above 40%. Effects range from false position indications to cascading system faults that can persist for the remainder of a flight, even after leaving the most affected zones.
Authorities have issued warnings to airlines, while Sweden’s defence minister said the government is prepared for continued threats.
13 member states of the European Union have called on the European Commission to respond to interference with GNSS in EU countries.
The interference originates in Russia and Belarus, as a result of the ongoing war with Ukraine.
The ministers for transport from 13 countries urged immediate and coordinated action in response, reports the Baltic Times. The joint letter was signed by the ministers of Lithuania, Latvia, Estonia, Germany, Slovakia, Finland, Slovenia, the Czech Republic, Italy, the Netherlands, Spain, Denmark and Romania.
In the joint letter, the ministers emphasize that since 2022, two types of interference to GNSS — jamming and spoofing — have been observed in the airspace of the Baltic Sea Region, posing a threat to various modes of transport, particularly civil aviation and maritime navigation.
The General Secretariat of the Council of the EU responded to the joint letter with an outline of potential actions.
Evaluate and coordinate the possibility to suspend the right to Russia and Belarus in the ITU to register the use of radio resources while GNSS interference is in progress. The lack of procedural legislation cannot be an excuse for deliberately contravening the spirit of the ITU Constitution and its general principles, endangering public health and life, without suffering any consequences.
Based on good practice of EU and NATO cooperation on critical undersea infrastructure, enhance civil-military coordination mechanisms among Member States for shared monitoring, data exchange, and possible response to GNSS interference. Explore the benefits of dual use of various equipment and measures to combat the risks caused by GNSS interference.
Intensify RFI monitoring by eligible national organizations and bodies, e. g. national regulator, police and military, and aggregate non-classified information on observed RFI to a publicly available near real-time monitoring and alert service on European level.
Accelerate the deployment of interference resistant GNSS services, especially the antispoofing features that are part of the Galileo program, e. g. authentication and/or encryption of signals exchanged between stations and user equipment.
Reassess the current reliance on GNSS-based navigation and develop resilient Positioning, Navigation and Timing (PST) services by deploying alternative or complementary systems, including ground-based legacy solutions. Simultaneously, upgrade and modernize conventional navigation infrastructures to serve as robust backups.
Promote industry-manufacturer collaboration for mitigation tools and updates. Support operator-level reviews of backup system readiness, ensuring non-GNSS alternatives are usable and practiced. 2 TREE2B 9198/25 EN
Draw the attention of critical infrastructure operators and unmanned system manufacturers to the risks that may arise from interference with GNSS.
Develop action plans for different domains (space, aviation, maritime, telecommunications) to avoid potential duplication of efforts and coordinate short-term and long-term measures at EU and national level.
Continue cooperation with all relevant stakeholders (ITU, ICAO, IMO, EASA, EMSA, IATA, EUROCONTROL). These actions, among others, could contribute to building the overall resilience of the critical infrastructure and strengthening safety and security in Europe.
The letter highlights the urgent need to accelerate the deployment of interference-resistant GNSS services, enhance the overall resilience of critical infrastructure, and strengthen safety and security across Europe.
“The current security environment demands a unified response to hybrid threats posed by hostile regimes, as well as close cooperation to strengthen Europe’s preparedness and resilience,” said Lithuanian Transport and Communications Minister Eugenijus Sabutis.
“Disruptions to GNSS signals have a direct impact on strategic sectors such as transport, energy, and telecommunications. To prevent potential incidents, we must act swiftly and decisively at the European Union level — not individually, but in a coordinated manner,” Sabutis said.
The interference is not random incidents but a systematic, deliberate action by Russia and Belarus, which can be used as a hybrid attack on strategic radio spectrum, essential for modern technology, regional safety and security, particularly in transportation.
Furthermore, the ministers call on the EU to increase diplomatic efforts to address the interference and apply pressure on the responsible parties, including legal action against responsible individuals and entities involved in the deliberate interference with GNSS signals, to enhance European safety and security.
“So far, the attempts by several Member States to address the problem have not brought any more tangible results,” the EU General Secretariats said. “Therefore, it is necessary to increase diplomatic efforts to address the interference and put the pressure on the responsible parties.”
The ministers propose intensifying radio frequency monitoring and enhance civil-military coordination mechanisms among Member States for shared monitoring, data exchange and possible response to GNSS interference. They also advocate for accelerating the deployment of interference-resistant GNSS services, particularly the anti-spoofing features of the Galileo program, and for upgrading and modernizing conventional navigation infrastructure.
Reports of increased interference include:
Lithuania: starting from 556 cases in March 2024 to 890 in October 2024 and 1185 in January 2025
Latvia: 790 cases in October 2024 to 1288 cases in January 2025
Estonia: 1150 cases in October 2024 and 1085 cases in January 2025
Poland: 1908 cases in October 2024 to 2732 cases in January 2025.
InfiniDome has released GPSdome 2, its newest anti-jamming solution. The cost-effective and lightweight device provides simultaneous dual-frequency protection from three directions of attack.
GPSdome 2 is a high-end solution tailored to defend small- to medium-sized tactical UAVs as well as manned and unmanned ground vehicles.
Disruptions in critical positioning, navigation and timing (PNT) data mean loitering munitions that never find their targets, UAVs that fall to the ground, and ground vehicles that cannot be managed.
With a small form factor (500 g, 87 mm x 91 mm x 61.55 mm) and minimal power consumption, GPSdome 2 is suitable for loitering munitions as well as drones and UAVs, increasing resiliency while prolonging mission time and providing a superior return on investment. Fully retrofit and completely standalone, the system is compatible with almost any off-the-shelf GNSS receiver on the market as well as standard active GNSS antennas, meaning that it can be integrated into existing GPS systems or into new product lines, manned or unmanned.
With sophisticated algorithms and a proprietary RFIC, GPSdome 2 analyzes RF interference in the environment and combines multiple antenna patterns to create and dynamically steer three nulls in the direction of any hostile signal.
GPSdome 2 provides simultaneous dual-frequency protection (GPS L1 + L2 or GPS L1 + GLONASS G1), creating up to three nulls, protecting from three jamming directions within each band in real time, making it suitable for PNT applications.
The GPSdome 2 is a dual-use, non-ITAR device and comes with optional mil-spec compliance. It has been chosen by an Israeli defense contractor for integration with its platforms.
AS CAT STEVENS (yes, he’s back to using his old name) famously sang on “Wild World”:
“… take good care Hope you make a lot of nice friends out there But just remember there’s a lot of bad and beware Beware.”
While he was talking about a girlfriend leaving him, the warning can just as well apply to GNSS users — especially those relying on GNSS for safety-of-life navigation and the maintenance of critical public infrastructure systems.
GNSS signals are relatively weak and they are susceptible to unintentional and intentional jamming that can make reception of the signals difficult or impossible. The jamming of radio signals to hinder reception is nothing new. It’s been used by those wanting to interfere with the use of the radio spectrum ever since radio became an important tool for communication and navigation in the early 20th century. Jamming has been used in hot wars to try to defeat military communication as well as in cold wars to try to prevent a perceived enemy from broadcasting to a particular country’s citizens. Notably, the shortwave radio broadcasts from Western countries were jammed by the former Soviet Union. And even today, broadcasts directed at China, Cuba and some other countries are regularly jammed.
GNSS is also being intentionally jammed on a regular basis in some parts of the world for various purposes including the protection of politicians and civilian infrastructure and to foil GNSS-guided munitions. But while directed at supposed threats, the jamming affects all GNSS receivers in a certain radius of the jammer. Such jamming activities are being reported in the popular press with an increasing frequency.
While GNSS jamming is receiving increased attention in our troubled world, even more pernicious is GNSS spoofing. Spoofing is the attempt to mimic GNSS signals to try to trick a receiver into tracking them and thereby compute a wrong position and/or time at the receiver. This can have disastrous consequences if not detected immediately and the use of GNSS deactivated.
So, how do you detect GNSS signal jamming and spoofing? We have discussed this issue in several columns over the years, but in this month’s column, a team of researchers from Stanford University and the University of Colorado describe how they are using relatively inexpensive equipment and sophisticated software and analyses to detect and warn of GNSS jamming and spoofing. Clearly, they are heeding Cat Stevens’ warning.
By Leila Taleghani, Fabian Rothmaier, Yu-Hsuan Chen, Sherman Lo, Todd Walter, Dennis Akos and Benon Granite Gattis
GNSS signals are extremely low power by the time they reach users on Earth and are easily overwhelmed by nearby terrestrial signals. Such signals can interfere with a user’s ability to receive the desired GNSS signals or, even worse, replace them with simulated signals that cause the user to obtain the wrong position or time estimate. Two major types of radio-frequency interference (RFI) threats have been identified: jamming and spoofing. Jamming results from emissions that do not mimic GNSS signals, but interfere with the receiver’s ability to acquire and track GNSS signals. Spoofing is the emission of GNSS-like signals that may be acquired and tracked in combination with, or instead of, the intended signals.
Both threats have been studied at length by researchers, and their presence around the globe has been reported even in the popular press. Some research has been done into the prevalence of spoofing. Even so, there is no well-developed understanding of how widespread these threats are.
Terrestrial interfering signals may be fairly weak and only effective in a limited area. Complex environments with buildings or terrain may further limit their effective area of influence and hinder the ability of external interference detection. To create a better understanding of the presence and characteristics of jamming and even spoofing, we are developing a low-cost RFI detector based on a commercial, off-the-shelf GNSS receiver: the u-blox F9. We are pairing this receiver with a Raspberry Pi computer and are developing custom software to monitor the receiver outputs and store data surrounding interesting events.
We are developing a toolset in MATLAB and C/C++ with the intention of processing and analyzing the u-blox data. The toolset includes functionality to decode selected u-blox messages that contain parameters of interest. These metrics include automatic gain control (AGC), carrier-to-noise-density ratio (C/N0) and spectral power. They also include raw pseudoranges from multiple constellations and internal u-blox interference metrics. With the volume of data that can be gathered from continuous monitoring, we have begun characterizing nominal performance and developing approaches to spoofing and jamming detection. The publicly available code can be accessed through our Git Repository at https://github.com/stanford-gps-lab/navsu.
With the raw pseudoranges and downloaded broadcast ephemeris data, we compute navigation solutions using different combinations of constellations and frequencies. When the individual and multi-constellation position solutions are compared to each other, discrepancies can be flagged and investigated for possible interference. We have begun characterizing nominal power metrics such as AGC and C/N0. With the quantity of data that we can get from the RFI monitor, we are working to characterize other receiver-specific parameters such as the u-blox continuous wave (CW) jamming indicator. We leverage data collected under nominal and jammed conditions to understand and identify a threshold for what can be considered interference.
Many different methods have been proposed for GNSS interference detection and mitigation with large-scale data at multiple locations. In this article, we present our data-selection process, our development of thresholds for determining interference, and results from three u-blox receivers set up at different locations in the United States to glean information about nominal (non-spoofed) conditions. We inform our thresholds and analysis tools using datasets from nominal conditions, and then compare their performance to a dataset containing RFI events from a government-sanctioned jamming and spoofing test. Our results display how we leverage simple and powerful metrics informed by a low-cost receiver to understand nominal noise environments and successfully identify jamming and spoofing events.
Data and Metrics
We collect and analyze a variety of data types and metrics to help identify and characterize jamming and spoofing occurrences. The receiver model we started with, u-blox ZED-F9P-02B, can monitor two different RF bands and many signals, including GPS L1C/A, L2C; GLONASS L1OF, L2OF; Galileo E1B/C, E5b; BeiDou B1I, B2I; QZSS L1C/A, L1S, L2C; and SBAS L1C/A. It has 184 channels, which can be configured to sweep through an array of signals to be monitored. We are also developing monitors based on the recently released ZED-F9T-10B, which is capable of L1 and L5 signal reception. TABLE 1 describes which version of the u-blox receivers each dataset comes from.
TABLE 1. Locations of u-blox monitor for nominal noise environment characterization and jam/spoof test. (Data: Authors)
L1 and L5 are the primary frequencies used for aviation, hence a monitor for these frequencies would be more useful for protecting aviation than the F9P, which is only capable of L1 and L2 reception. The available data includes raw measurements such as code and carrier phase, position estimates, power level estimates including C/N0, AGC and spectral power. It also has active CW interference detection. These metrics are all necessary for the consistency checks and power monitoring methods we summarize in this article. Consult our conference proceedings paper for details (see Acknowledgments). By examining all of these signals and measurements, we can observe changes in the RF environment and detect inconsistencies in the received signals.
Data Logging. The u-blox receiver logs messages in a specific format. The message types important to log are selected based on the desired data. Due to limited bandwidth, we prioritized messages that efficiently include all desired parameters for the interference detection methods we describe in this article. We have used both the u-blox F9P and the u-blox F9T.
To characterize nominal noise environments, u-blox receivers were set up at three locations: Stanford University, the University of Colorado (CU) in Boulder, and at the Colorado Springs airport. All measurements from satellites below an elevation angle of 5 degrees were ignored. The results from these locations are summarized below. Results from a jamming/spoofing test sanctioned by the U.S. Department of Homeland Security are presented and labeled with the acronym “GET-CI” (GPS Testing for Critical Infrastructures) in the subsequent discussion. Table 1 describes the parameters of the u-blox receiver at each location.
Positioning Metrics Development.The nominal error of the single- and multi-constellation position solutions is made by noting the difference between the computed position and the known truth. The inter-constellation consistency check is defined as the difference between the positions computed from two constellations, with no reference to a known truth position. To analyze the nominal differences in the north, east and down (NED) directions, we use the position covariance matrix, R, computed in the least-squares solver, to set a covariance-bound threshold. The covariance for each constellation is assumed independent. We present our results using this threshold in our results sections.
Our results in FIGURE 1 show that the Galileo position solution variance is higher than the dual-constellation and GPS-only solution. This is attributed in part to the fact that Galileo, while operational, has not filled out all planned satellite slots and therefore has fewer satellites and worse geometry than GPS.
FIGURE 1a. Map visualization of the comparison among position solutions computed using only GPS, only Galileo and a combined GPS plus Galileo dual-constellation solution at Colorado Springs. (Image: Authors)
FIGURE 1b. Map visualization of the comparison among position solutions computed using only GPS, only Galileo and a combined GPS plus Galileo dual-constellation solution at CU Boulder. (Image: Authors)
FIGURE 1c. Map visualization of the comparison among position solutions computed using only GPS, only Galileo and a combined GPS plus Galileo dual-constellation solution at Stanford. (Image: Authors)
Nominal Noise Results
Here are some of our positioning and power monitoring results under nominal reception conditions.
Positioning. Based on the methods described earlier, we present a selection of our results from the positioning consistency checks. We present several informative visualizations of the error between the computed position solution and the known truth of each u-blox receiver and use the covariance threshold to bound the raw error. The error for dual-constellation, single-constellation and inter-constellation consistency checks are all displayed and compared to one another. The pseudorange residuals and their accompanying chi-squared (χ2) statistic are also evaluated and compared for the GPS and Galileo single-constellation position solutions.
Positioning Consistency Comparison Maps. From the maps in Figure 1, we observe that Galileo has the highest error, followed by GPS, and then the dual-constellation solution. The map also serves as a method to spatially visualize the tails of the error distribution.
NED Time Histories. We compare the time history of the dual-constellation, GPS and Galileo position solution error to the three sigma (3σ) covariance bound computed at each epoch (see FIGURE 2). We also compare the GPS vs. Galileo inter-constellation difference to the 3σ covariance bound. The covariance bound is never crossed, indicating that 3σ threshold is conservative for both the error and the inter-constellation difference between GPS and Galileo.
FIGURE 2a. Dual-constellation north-east-down error vs. known truth, bounded by a 3σ threshold, at Colorado Springs. (Image: Authors)
FIGURE 2b. Dual-constellation north-east-down error vs. known truth, bounded by a 3σ threshold, at CU Boulder. (Image: Authors)
FIGURE 2c. Dual-constellation north-east-down error vs. known truth, bounded by a 3σ threshold, at Stanford. (Image: Authors)
Pseudorange Residuals and χ2 Statistic Threshold. Pseudorange residuals have a long history of being used as a consistency check between range measurements. As an example, the pseudorange residuals for the GPS position solutions are shown in FIGURE 3, and their corresponding χ2 statistic is shown in FIGURE 4.
FIGURE 3a. GPS pseudorange residuals at Colorado Springs. (Image: Authors)
FIGURE 3b. GPS pseudorange residuals at CU Boulder. (Image: Authors)
FIGURE 3c. GPS pseudorange residuals at Stanford. (Image: Authors)
FIGURE 4a. GPS χ2 and probability of false alert (PFA) threshold for the nominal noise environments at Colorado Springs. (Image: Authors)
FIGURE 4b. GPS χ2 and probability of false alert (PFA) threshold for the nominal noise environments at CU Boulder. (Image: Authors)
FIGURE 4c. GPS χ2 and probability of false alert (PFA) threshold for the nominal noise environments at Stanford. (Image: Authors)
The χ2 statistic is computed using the finite pseudorange residuals at each epoch, where the degrees of freedom are n − 4, where n is the number of satellites used at that epoch and 4 is the number of variables solved for (x, y, z, and the receiver time offset) when using a single constellation. A p-value is computed using the cumulative distribution function (CDF) of the χ2 statistic, and indicates the probability that the χ2 statistic at each epoch would be greater than the observed value. The statistic is compared to a theoretical 10−9 probability of false alert (PFA) based on the theoretical χ2 and the actual degrees of freedom of each epoch. Very low values for the χ2 statistic, such as those obtained with Galileo, are attributed to regions where very few satellites are in view, thus decreasing the degrees of freedom. Any spikes in the pseudorange residuals are also reflected with a higher χ2 statistic and low p-value, though those residuals are de-weighted in the position solution and ultimately do not trigger the 10−9PFA threshold or the 3σ threshold, thus indicating that a 10−9PFA is a conservative threshold.
Power Monitoring. For each nominal location with a u-blox receiver, we analyze results from the power-monitoring metrics mentioned earlier. We also observe results from the internal u-blox jamming indicators in a region where a possible RFI event was observed.
For power monitoring, we analyze spectral power and programmable gain amplifier (PGA) results.
For the nominal noise environments, the spectral power, PGA and corresponding C/N0 results indicated no significant anomalies.
Threshold and Metric Validation Results
An examination of thresholds and other metrics are important for characterizing RFI.
GPS Testing for Critical Infrastructure. From a DHS-sanctioned RFI testing event, we identify five regions of interference or spoofing. To identify the interference, we use a combination of the power and positioning metrics as well as the thresholds we developed through the characterization of the nominal noise environments described in the previous sections of this article.
We use the thresholds and tests we’ve developed to identify regions of spoofing and RFI events (labeled C I1–C I5) in the GET-CI dataset. For ease of comparison, all regions are labeled on plots that display the full 5.5 hours of data collection. All details as to the truth location and time of the test have been removed. C I1 is identified through the power metrics. C I2–C I5 are identified as regions that the NED difference between GPS and Galileo clearly crossed the 3σ threshold in all three directions, as visualized in FIGURE 5.
FIGURE 5a. Map view of solutions using GPS, Galileo and GPS plus Galileo for the DHS-sanctioned RFI testing event (identifying coordinates and physical features removed). (Image: Authors)
FIGURE 5b. Corresponding log-scale visualization of the GPS vs. Galileo position solution difference in the north-east-down directions. (Image: Authors)
From our pseudorange residuals, it appears as though the most significant interference events happened on the GPS constellation, as indicated by the high pseudorange residuals that fall into the C I2 and C I5 regions. Using the GPS χ2 statistic and p-value computations, we determined that the regions that crossed the 10−9 PFA threshold line are consistent with the regions of interference identified in Figure 5. The Galileo χ2 statistic, p-values and pseudorange residuals all show signs of possible interference. These regions are explored more in the power monitoring discussion below.
Since the GPS pseudorange residuals and χ2 statistic results show more signs of spoofing than the Galileo ones, we explore the Galileo-only position solution. Because the truth position is unknown, we take a point during the non-C I regions and define this as the “truth,” that is, a point in the position solution we believe has not been subject to spoofing. Any references to a truth position are from a position recognized as “truth” through post-processing rather than from a pre-determined and known location.
The p-values dip in each of the C I regions, but are lowest in regions C I5. Combined with the fact that the pseudorange residuals and NED error are the highest in C I5, we identify this as the region that likely experienced a significant spoofing event. We determined from an outlier at the beginning of the C I5 region (see Figure 5) that even the Galileo constellation is not immune to the spoofing in this scenario.
To further check the accuracy of our determination that GPS was spoofed, we evaluated the histograms of the Galileo error. With the biggest outlier in C I5 removed, we saw that the error appears relatively Gaussian, with some outliers and possible multi-modal behavior that were also seen in the nominal locations. The variance was higher than was observed at nominal locations, which could be attributed both to the presence of known RFI events, the fact that the nominal noise environment at the RFI event test has not been characterized (that is, it is possible there is a noisier nominal environment at this location), and that the “truth” position was not a known truth but obtained through post-processing of a dataset with increased RFI. Normalized error indicates that the error does not cross the 3σ threshold in any NED direction, further supporting the assertion that 3σ is a conservative threshold.
Important to note is that the major outlier around T+3.5 hours is visible in the NED plot (Figure 5), but the corresponding histograms do not contain that outlier. This indicates that the covariance also increases at that point. It dictates a need to monitor the covariance bound itself, as well as the positioning error. The NED time history plot and the raw error histograms serve this purpose, since it is clear that if we were to be only looking at the error normalized by 3σ, we would not have found significant evidence of the outlier, since the normalized error barely passes the 3σ threshold. This further supports our methods of combining multiple metrics, thresholds and visualizations rather than relying on a single metric to identify jamming and spoofing.
From the Galileo solution analysis, we increase our confidence that we have identified the regions with interference. We removed those areas and looked at the GPS vs. Galileo inter-constellation consistency difference. The normalized differences were now mostly within the 3σ threshold, and the raw error displayed some Gaussian behavior and is no longer on the order of the 105-meter error we were seeing in Figure 5. While these regions still have a higher error than nominal conditions and thus still display signs of interference, we are able to use our spoofing analysis to identify epochs in which we should not trust the GNSS. Using times outside those regions, we are able to figure out a reasonable truth position within 20 meters rather than 200 kilometers.
Positioning analysis using the inter-constellation consistency check is a powerful tool for determining the reliability of a position solution, even when the truth location is unknown. With the power metrics, we can further corroborate the positioning results, as well as find events indicating interference that the positioning metrics were unable to track.
FIGURE 6a. GPS pseudo range residuals for position solutions computed using only the GPS constellation. (Image: Authors)
FIGURE 6b. Galileo pseudorange residuals for position solutions computed using only the Galileo constellation for the DHS-sanctioned RFI testing event. (Image: Authors)
Next Steps and Summary
Leveraging the raw data collected by u-blox receivers in multiple locations with different nominal noise environments, we have developed the toolsets to do inter- and intra-constellation consistency checks to monitor for jamming and spoofing. Many further observables usable for RFI detection are being recorded by the u-blox receivers. Several power monitoring metrics have been evaluated in a preliminary analysis. The next step is to further characterize metrics such as C/N0, AGC and u-blox internal jamming metrics under nominal conditions.
In summary, the tools we have developed so far show that the u-blox receiver will allow for many different consistency checks on a variety of parameters to be running simultaneously. It would be difficult for a spoofer to interfere with all the dimensions we have covered in our detector. Continuously monitoring a wide variety of parameters will increase the chance that we are able to detect interference, thus lowering the chance that a spoofer is able to evade detection.
Acknowledgments
We gratefully acknowledge the support of both the FAA Satellite Navigation Team and The Aerospace Corporation under their university partnership program. We especially wish to thank Steve Lewis of Aerospace for his support and guidance throughout the development of this project. This article is based on the paper “Low Cost RFI Monitor for Continuous Observation and Characterization of Localized Interference Sources” presented at ION ITM 2022, the 2022 International Technical Meeting of the Institute of Navigation, Jan. 25–27, 2022.
LEILA TALEGHANI recently graduated with her MS degree from Stanford University in aeronautics and astronautics and is now a navigation engineer at Trimble.
FABIAN ROTHMAIER is a navigation research and development engineer at Airbus Defence and Space in Munich, Germany, and a former a Ph.D. student at the Stanford GPS Laboratory.
YU-HSUAN CHEN is a research associate at the Stanford GPS Laboratory.
SHERMAN LO is a senior research engineer at the Stanford GPS Laboratory.
TODD WALTER is a research professor in the Department of Aeronautics and Astronautics at Stanford University.
DENNIS AKOS is a professor with the Aerospace Engineering Sciences Department at the University of Colorado, Boulder.
BENON GRANITE GATTIS is a laboratory assistant and undergraduate student in the Aerospace Engineering Sciences Department at the University of Colorado, Boulder.
The U.S. Department of Defense wants help making sense of commercially and publicly available information that could be used to detect GNSS disruptors, especially over large areas.
Obtaining the ability to detect and geolocate GNSS disruptions has been cited as an unmet need in a number of U.S. national policies and plans dealing with positioning, navigation and timing.
The recently posted solicitation calls the project “HARMONIOUS ROOK – Situational Awareness for Intentional Disruption of Global Navigation Satellite System (GNSS) Users.” The solicitation says:
“The Department of Defense (DoD) seeks commercial solutions leveraging machine-driven analytics and datasets derived from publicly/commercially available information (PAI/CAI) to provide a situational awareness capability for intentional global navigation satellite system (GNSS) disruptions. This solicitation is particularly focused on persistent, large-area coverage of falsified GNSS emitters that result in localized spoofing phenomenology.”
Studies and analyses by non-profit organizations and commercial entities have demonstrated the ability of non-governmental organizations to do this kind of work and produce remarkable results. In 2017, our Resilient Navigation and Timing Foundation detected and reported on widespread GPS spoofing in the Black Sea.
This acquisition is being led by the Defense Innovation Unit, or DIU. The unit was specifically created to accelerate the adoption of commercial technology and services by the defense and national security establishments. While letting a traditional DoD contract for a prototype can often take up to 18 months, DIU aims to award contracts within 60 to 90 days of identifying the problem.
To do this, DIU uses the government’s “commercial solutions opening” process, which is designed to be simple and quick.
Companies who provide analytic services and those who have unique data sets are both encouraged to apply. The deadline is August 23.
Dana A. Goward is president of the Resilient Navigation and Timing Foundation
An Interim Armored Vehicle “Stryker” and AH-64 Apache helicopters with Battle Group Poland move to secure an area during a lethality demonstration as part of Saber Strike 18 in June 2018. (Photo: U.S. Army/Spc. Hubert D. Delany III, 22nd Mobile Public Affairs Detachment)
A surveillance system is demonstrated during a Naval Information Warfare Systems Command (NAVWAR) exercise. (Photo: Rick Naystatt/U.S. Navy)
The U.S. Defense Innovation Unit (DIU) is asking for commercial solutions to fight GNSS disruptions, including jamming and spoofing.
DIU is particularly asking for “solutions leveraging machine-driven analytics and datasets derived from publicly/commercially available information to provide a situational awareness capability” against intentional disruptions.
Responses to “HARMONIOUS ROOK — Situational Awareness for Intentional Disruption of Global Navigation Satellite System (GNSS) Users” are due by Aug. 22.
DIU is a Department of Defense organization focused exclusively on fielding and scaling commercial technology across the U.S. military to help solve critical problems.
The solicitation is focused on “persistent, large-area coverage of falsified GNSS emitters that result in localized spoofing phenomenology.”
It cites intentional manipulation of GNSS signals as enabling “nefarious activities, to include narcotics trafficking, unapproved operation of autonomous vehicles, illegal fishing and sea-borne piracy.”
“Additionally, nation-state use of GNSS jamming or spoofing systems may extend beyond the area of conflict, causing deleterious effects on civilian populations,” the solicitation states. “Such activities degrade or deny critical geolocation capabilities and further introduce hazards to safety-of-life-navigation, critical infrastructure, and emergency response services. “
The U.S. Army’s Assured Positioning, Navigation and Timing/Space Cross-Functional Team has approved the Navigation Warfare Situational Awareness Abbreviated Capability Development Document (A-CDD), signed March 25.
The A-CDD validates the operational need and enables experimentation and rapid prototyping for NAVWAR-SA capabilities for the warfighter.
NAVWAR is deliberate offensive and defensive actions to assure friendly use and prevent adversary use of positioning, navigation and timing information. NAVWAR supports Multi-Domain Operations as an enabler to precision fires, movement and maneuver, force tracking, and a host of data networks that tie personnel and weapon systems together into a joint or coalition force.
NAVWAR-SA provides the capability to detect, identify and locate sources of interference that deny or degrade reception of PNT. It is intended to validate PNT signal integrity and provide users with indication and warnings of the presence and intensity of interference.
NAVWAR-SA will also characterize the operating environment through the integration of multiple sensors that are able to detect, identify and geolocate sources of intentional and unintentional interference.
William Nelson, Director, APNT CFT
“This A-CDD will enable us to accelerate critical NAVWAR technology development and streamline the process of expediting an operationally relevant system to our warfighters,” said Willie Nelson, director for the APNT/Space CFT. “This capability will enhance our ability to provide real-time situational awareness of PNT reliability to soldiers and commanders on the battlefield, which will enable Long-Range Precision Fires and support freedom of maneuver of large scale ground combat operations.”
NAVWAR-SA will give the Army Forces the ability to “sense” the PNT environment in real-time, allowing commanders and units to maneuver with confidence and with precision when the global positioning system is degraded or denied. This is critical element of NAVWAR operations.
The APNT CFT coordinated with organizations across the modernization enterprise to get the NAVWAR-SA A-CDD approved. The Army Capability managers for Space and High Altitude played a major role in developing the written requirement and getting it through the approval process.
“The requirements provided in the NAVWAR-SA A-CDD are a first step in developing dedicated NAVWAR capabilities for our soldiers and are a key enabler in enhancing lethality in combat operations,” said Col. Tim Dalton, Army Capability manager for Space and High Altitude director.
The A-CDD details methods to leverage new and existing solutions for rapid prototyping, testing and soldier assessment. The APNT/Space CFT will utilize the “buy, try and decide” process to accelerate the development of critical enabling technologies and streamline the process of transitioning a scalable, interoperable and agile capability to the field. This process will inform NAVWAR-SA requirements for current and future Army systems.
“NAVWAR-SA will strengthen the Army’s ability to conduct military operations in PNT-challenged environments,” said David Pinckley, NAVWAR director for the APNT/Space CFT and chairman of the NATO NAVWAR Capabilities Team. “The unfortunate reality is that our systems will continue to be challenged by our adversaries so we are working with our joint and coalition partners to preserve military capabilities while mitigating impacts of interference.”
NAVWAR is one of the three APNT/Space CFT Signature Efforts, which will deliver offensive and defensive NAVWAR capabilities in conjunction with existing Department of Defense NAVWAR policies.
Joint and coalition forces conducting military operations will employ NAVWAR-SA to coordinate and implement mitigating actions to overcome PNT challenged environments.
The APNT/Space CFT plans to assess and test NAVWAR-SA prototypes later this year, during Project Convergence 21 and the CFT’s annual PNT Assessment Exercise at the White Sands Missile Range, New Mexico.
In its closing days, the Trump administration issued several new policy documents affecting positioning, navigation and timing (PNT) issues.
Some have questioned the long-term impact of these, given the significant policy differences between the previous and current administrations. Yet policies in relatively non-controversial areas such as PNT are generally developed by career personnel who tend to remain in place from administration to administration. While they must adhere to the philosophical tenets of extant elected officials, these policies tend to endure longer than others.
Even if this weren’t the case, considering the wealth of other issues the new administration is grappling with, these new policies could remain in force for some time, even if the new regime ultimately decides to change them.
Several themes run through many of the documents. These include:
Space-based PNT is vulnerable and must be protected.
The first of these late-term documents to be published was the National Space Policy issued on Dec. 9, 2020. Highlights and possible impacts for the PNT community include:
A goal to “Promote and incentivize private industry” could have implications for low-Earth orbit (LEO) PNT services.
A goal to “Increase the assurance of national critical functions” could include GPS/PNT resilience.
A pledge to “Safeguard space components of critical infrastructure” undoubtedly includes GPS. The section also has ominous statements about U.S. responses to purposeful interference and tasks the Defense and Homeland Security secretaries with having those responses ready.
Another pledge to “Maintain and Enhance Space-based Positioning, Navigation and Timing (PNT) Systems” is followed by eight explanatory paragraphs, many of which repeat previous policy. One new item is a promise to invest in detection and mitigation of harmful interference. A mention is also made of the need for multiple and diverse PNT sources, and responsible use of PNT, echoing the February 2020 Executive Order on the subject. Both of the latter two mentions were in the context of critical infrastructure and mission essential functions versus the security of the nation and economy as a whole.
Congress mandated a GPS backup technology demonstration in 2017, and $10 million was subsequently provided for that purpose. Various internal government delays resulted in the project not getting underway until March 2019. It concluded about a year later.
While some people have been critical, it is important to remember the report documents 11 vendor demonstrations, not engineering tests. Technologies were demonstrated in different locations and under differing conditions.
There is no silver bullet for meeting the nation’s needs. It must be a system of systems.
Also, the amount of effort and equipment in the demonstrations depended in some cases upon infrastructure available and the amount of money the government and vendors were able to spend. This meant that at least one technology was “demonstrated” mostly by explaining the concept, and other vendors were able to only partially demonstrate their technologies.
All of that said, the report offers valuable information about how America should make its national PNT much more resilient and reliable. First, it reinforces DOT’s message that there is no silver bullet for meeting the nation’s needs. It must be a system of systems. Second, the report goes further and says what that system of system should look like: “Those technologies are LF and UHF terrestrial and L-band satellite broadcasts for PNT functions with supporting fiber-optic time services to transmitters/control segments.”
From a policy perspective, this is a huge step forward. It resolves previous ambiguity and positions the nation to establish a resilient PNT architecture, one that will do more than be a “GPS backup.” It will be an architecture that will better support current applications and better enable emerging ones like autonomy, 5G and “NextG.”
Published one hour and fourteen minutes before the end of the administration on inauguration day, this plan was mandated as part of the February 2020 Executive Order on responsible use of PNT. By taking a comprehensive look at how we can do better, it provides an interesting outline of the challenges associated with America’s current over-reliance on GPS. While not a policy or directive document, it does suggest two or three departments and agencies that might be tasked with addressing each challenge.
It also addresses the need for interference detection and monitoring, and diverse sources of PNT.
This directive was published five days before the end of the administration and replaced the previous policy, 2004’s NSPD-39.
While the old policy calls for performance monitoring of GPS signals, the new one also has investment in interference detection and monitoring as a goal.
Perhaps the most significant change in the new policy was the absence of the words “backup capability” and the lack of a mandate for DOT to lead its establishment. Yet the policy hammers home multiple times the need for more than GPS as a source of PNT. And it doesn’t abandon the idea of government involvement in making that happen.
In addition to reinforcing Executive Order 13905 on responsible use of PNT, the directive defined a new (for presidential policies) term. “Alternative PNT Service” was described as “a PNT service that has the capability to operate completely independent of, or in conjunction with, other PNT services.” The directive goes on to say that “Multiple, varied PNT services used in combination may provide enhanced security, resilience, assurance, accuracy, availability and integrity. An alternative PNT service allows a user to transition from the primary source of PNT signals in the event of a disruption or manipulation.”
And while the policy does not say the government will establish or support an alternative PNT service, it comes pretty close. One of its goals is “Invest in… as appropriate, alternative sources of PNT for critical infrastructure, key resources, and mission-essential functions.”
It goes on to task the departments of Defense, Homeland Security and Transportation with making that happen.
So “backup” is out, “alternative PNT” is in. We agree words are important and are happy to have the new words. Let’s hope the new administration will match the new words with action (as appropriate).
Raytheon Intelligence & Space, a Raytheon Technologies business, delivered its 3,000th MAGR 2000-S24 GPS system to the U.S. Air Force. The MAGR2K is a secure, resilient GPS receiver that allows the warfighter to navigate the battlespace with protection against interference and jamming.
The MAGR2K is an upgrade to the legacy miniaturized airborne GPS receivers and is in service aboard 20 types of fixed-wing and rotary-wing platforms from Department of Defense and Foreign Military Sales customers.
“In the battlespace, disruptions to navigation are not an option,” said Eric Ditmars, vice president of Secure Sensor Solutions at RI&S. “Our MAGR2K GPS receivers enhance GPS acquisition and performance ensuring military forces reliable and assured GPS data they can act on. Delivery of the 3,000th unit is a significant milestone for our team.”
Raytheon Intelligence & Space continues to upgrade the MAGR2K technology to stay current with the evolving battlespace. Development is underway for the MAGR-2K-M, which uses the company’s M-code technology.
The first production readiness units are undergoing platform integration on the U.S. Air Force’s B-2 platform.
B-2 Spirit multi-role bomber capable of delivering both conventional and nuclear munitions. In December 2017, the Air Force completed a series of successful flight tests of M-code GPS using a Raytheon Company receiver on board a B-2 Spirit at Edwards Air Force Base, California. (Photo: U.S. Air Force/Bobby Garcia)
NovAtel’s GPS Anti-Jam Technology (GAJT) product lines achieved a milestone of thousands of units shipped worldwide in 2020. Despite COVID-19, 2020 has proven to be one of NovAtel’s most successful years in protecting positioning, navigation and timing (PNT) from cyber electromagnetic activities (CEMA) for military and civil organizations, the company stated in a press release.
Jamming and interference are growing threats, from a crowded RF spectrum to malicious jamming attempts. However, the GNSS market is responding with anti-jam technologies. Across the world — on land, in the air and at sea — NovAtel customers use GAJT to protect their GNSS navigation and precise timing receivers from intentional jamming and unintentional interference.
The GAJT portfolio includes commercial off-the-shelf solutions with short order lead times for rapid deployment. The range of products can be readily integrated into new platforms or retrofitted into legacy fleets.
Photo: Hexagon | NovAtel
The GAJT-710, its smaller counterpart GAJT-410 and the GAJT-AE variants are used worldwide to protect PNT against jamming and interference no matter the environment.
Beyond defense, GAJT enables users to be proactive against cyber electromagnetic activities using situation awareness technology to indicate the presence and direction of jamming signals.
“Jamming and interference are growing threats worldwide. GAJT protects our customers no matter where they operate,” said Steve Duncombe, executive VP of Aerospace and Defense at NovAtel. “We’re proud to achieve this milestone during a challenging 2020 and will continue delivering assured positioning in our customers’ critical applications with extremely short delivery times.”
Schematic of the GNSS interference detection and analysis system GIDAS. (Image: OHB Digital Solutions)
In September 2020, the first GIDAS monitoring stations were installed at the Czech airport in Brno.
GIDAS — GNSS Interference Detection and Analysis System — enables continuous 24/7 monitoring of the GNSS frequency bands within a defined region to automatically detect, classify and localize intentional interference from jamming and spoofing.
GIDAS can raise the alarm in real time, identify the type of interference, and then pinpoint the location of these dangerous portable devices causing the interference so the authorities can take immediate remedial action. It considerably improves safe and robust operation of GNSS receivers, terminals and applications.
GIDAS was developed by OHB Digital Solutions and Joanneum University of Applied Sciences through ESA’s Navigation Innovation and Support Programme (NAVISP).
The system works autonomously and is designed to be easily deployed. It is scalable and flexible; it can be used as a standalone monitoring station or upgraded to a network of stations.
Recent GNSS interference attacks include:
shutdown of navigation equipment at Newark airport
GNSS attacks of North Korea against South Korea
117 incidents within one day at Kaohsiung airport in Taiwan
a U.S. military drone forced to land
a 65-meter yacht drifting off course during field trials
failure of emergency pagers, traffic management systems and ATMs in San Diego caused by U.S. Navy jamming.
“In recent years, GNSS applications have increasingly become the target of intentional interference attacks, since GNSS is widely used in safety and value-critical applications,” said Andreas Lesch, CEO of OHB Digital Solutions. “GIDAS detects, classifies and localizes GNSS interference signals and thus reduces the already existing threat of receiving worse accuracies or even denial of service.”
The GIDAS system user interface helps to pinpoint interference. (Image: OHB Digital Solutions)
GIDAS monitors the GNSS L1/E1 frequency band and reliably detects and classifies intentional and unintentional interference sources using sophisticated algorithms. GIDAS consists of a high performance data processing unit including antenna and RF front-end, and a sophisticated software solution.
GIDAS is able not only to monitor GNSS-based position, velocity and time solutions, it monitors the received signal and baseband processing.
The system is composed of the following software modules:
Software-defined GNSS radio
Position, baseband and C/N0 monitoring
Jammer and spoofing parameter estimation
Localization capabilities through synchronization of several GIDAS systems
Graphical user interface
Initial GIDAS reports show an average of seven GNSS interference events per day. GIDAS was able to successfully classify the signal type in 96% of jamming cases that have occurred.
The document covers a number of details regarding the Ligado Networks and the advancement of 5G.
According to the document, former NASA Administrator Daniel Goldin claims that FCC’s approval of the proposal by Ligado Networks to repurpose satellite spectrum in the L-Band for high-power terrestrial use should be upheld because it will help advance American leadership in 5G technologies.
“Winning the race to 5G — against China and other countries — is important, but Ligado’s proposed network is largely irrelevant to 5G,” the GPS Innovation Alliance said in response. “The availability of Ligado’s spectrum for terrestrial use will not contribute to the advancement of 5G but will instead undermine U.S. Global Positioning System receivers and devices that are foundational to wireless technology in general, including 5G.”
In addition, the GPS Innovation Alliance’s stated in its ex party that the use of L-Band spectrum is not critical for 5G services.
Other points mentioned in the document include that Ligado’s spectrum is not internationally harmonized, significantly diminishing its effectiveness as a 5G band, and that Ligado’s proposed network simply will not offer a 5G service. According to the GPS Innovation Alliance, Ligado merely proposes to offer limited internet of things services, primarily delivered over custom private networks to specific geographic areas for limited vehicular and utility operations. Not only is this not a 5G service offering, but similar services are already being provided by wireless service providers, the alliance added.
