Signal Jammer Tech

Is it possible that networking phones collectively to operate as a comprehensive distributed antenna could provide a solution against Russian electronic warfare?

A company based in the United States, which is working on a system in Ukraine, indicates that networked cell phones with tailored software could represent an inexpensive and readily deployable response to the complex electronic warfare methods utilized by Russian forces.

Russian electronic warfare capabilities, which encompass signal jamming and GPS spoofing, pose significant challenges for Ukrainian troops in their operational effectiveness, particularly regarding the use of drones and advanced U.S. weaponry. The ability to detect and pinpoint enemy jamming devices often relies on sophisticated software-defined radios, which are typically provided to the United States and other well-funded military forces. Conversely, smaller militaries, such as Ukraine's, struggle to obtain these vital resources in large quantities due to budgetary restrictions.

The potential creation of an inexpensive system to detect enemy jamming apparatus could assist Ukrainian operators in regaining an edge over their better-equipped adversaries. This innovation could also transform the approaches taken by cellphone network providers to ensure their devices are resilient against sophisticated forms of attack.

Around the Christmas period of the previous year, the Ukrainian military made contact with Sean Gorman and his associates at Zephr, a company that specializes in reinforcing devices against GPS-signal interference. Zephr swiftly delivered six Android Pixel phones, equipped with their software, to Ukraine, and in April, they began conducting field tests near the frontlines in Donetsk.

In an interview with Defense One, Gorman explained that the phones were attached to drones, integrated into vehicles, and established on stationary platforms. They have also carried out controlled experiments utilizing their own signal jammerss to ascertain the precise location.

The foremost objective was to assess whether typical consumer smartphones, operating in unison within a network, could expose the existence of an entity attempting to interfere with GPS location data. The study revealed that by evaluating the GPS reception from various phones, they could identify when one or more devices were subjected to an attack.

Gorman remarked, "We are effectively taking advantage of the sensors found in mobile phones. The most significant sensor is the raw measurements from the global navigation satellite system (GNSS) that the device supplies. This includes automatic gain control (AGC), Doppler sensor data, carrier phase, code phase, and other metrics that smartphones gather regarding their distance from satellites, cell towers, and various network apparatus."

Manufacturers embed these sensors in cell phones to facilitate performance optimization, such as locating the nearest cell tower. The data collected from these sensors is integral to the GPS-processing software that enables phones to provide users with their precise location. By obtaining this information from a wide array of devices, it is possible to determine which phones may be compromised.

Gorman remarked that the computational AI operating in our backend, paired with the advanced techniques for processing signals and software, opens up numerous possibilities. Rather than depending exclusively on sensors or high-cost antenna arrays, one can achieve a great deal by networking mobile phones to act as a unified distributed antenna.

The evaluations also brought to light new findings concerning Russian electronic warfare.

Russia is engaging in the spoofing of GPS signals in the Baltic Sea, which results in receivers displaying false location information. NATO officials have indicated that this creates an unsafe scenario for passenger aircraft. A common strategy to mitigate drone threats involves GPS spoofing, which misleads the drone into thinking it is over an airport, necessitating a landing or retreat from no-fly zones.

On the frontlines in Donetsk, reports from Ukrainian soldiers frequently mention spoofing attacks on their drones. However, Gorman and his team have determined that a large portion of these incidents classified as "spoofing" are, in reality, high-powered jamming attempts. Since these jamming efforts operate within the same frequency bands as GPS or GNSS, they can mimic satellite signals, thereby creating the illusion of phantom or ghost satellites in locations where they cannot feasibly exist and still provide a signal, such as below the horizon.

Gorman articulated in a write-up for Defense One that the noise observed does not align with the usual characteristics of a GNSS signal; nevertheless, it does exhibit energy at the frequencies where the receiver is searching for satellite signals. The receiver employs signal-processing algorithms that utilize correlation techniques to identify and monitor satellite signals. The presence of a strong jamming signal can result in false correlations, misleading the receiver into believing it is detecting satellites that are not truly present.

The organization, now contracted by the Ukrainian government, is working to progress their research to not only detect cell phone jammer but also to accurately triangulate their positions, which would allow for their avoidance or removal.

Gorman indicated in an email that the advanced techniques being created will assess the location of signals of interest through three distinct inputs: 1. range-based localization inferred from power; 2. localization by area of effect; and 3. triangulation of jammers based on the angle of arrival. Each smartphone will detect the interference signal, log the last known position, and timestamp the reception, thus providing data points throughout the network. By centralizing and processing these signals, the system will effectively triangulate the position of the jammer.

The military of the United States is heavily investing in alternatives to GPS, which are generally referred to as alternative position, navigation, and timing, or Alt PNT, to assist people, drones, and other systems in ascertaining their geographical positions. However, these investments have frequently failed to produce significant returns.

Gorman remarked that the functionality of the system relies on an initial known position, and acquiring this position is almost unattainable without GPS assistance.

This networked approach is not intended to replace existing, more expensive military systems that are used for detecting and locating jammers. Instead, it offers a quick and cost-efficient solution for military forces like Ukraine and other groups vulnerable to jamming activities, including first responders. Furthermore, while it will not supplant the development of alternative positioning, navigation, and timing techniques, it could enhance their effectiveness.

Gorman proposed that there may be a significantly different way to approach this issue. Rather than concentrating all resources on Alt PNT and GNSS resilience, which are highly beneficial, it might be worthwhile to explore how this situation has evolved into a reality. He highlighted the need to effectively map and analyze the area in relation to the emitters, so that we can avoid those zones and eliminate the emitters.