RF border surveillance: a key line of defense for border security

With terrorism, human trafficking, and illegal immigration on the rise, border agencies are consistently addressing new challenges. They must find the right balance between ensuring that the free movement of people and goods is as seamless as possible for economic prosperity while simultaneously protecting their borders against hostile threats and unsanctioned activities.


However, conventional foot and vehicle border patrols are an impractical solution for large border surveillance operations—a modern solution would be to construct a “smart” border. 


What is the problem with conventional border security monitoring?

Not only are threats intensifying, but they are also becoming increasingly high-tech to evade detection, posing serious concern to border security officers. Also, international boundaries can cover hundreds if not thousands of kilometers, traversing inhospitable terrains and large areas of open water, making routine foot patrols difficult and resource-heavy. 

Examples of huge borders include the recent NATO border expansion with the accession of Finland, which adds over 1,340 km (830 miles), or the US-Mexico border, which is a staggering 3,145 km (1,954 miles). In this context, conventional border enforcement processes like mobile patrol units, video surveillance cameras, or building walls and fences are becoming less effective. For nations situated on contested borders with near-peer threats, border surveillance systems once built for migrant activity are not suited to track hostile military or “irregular grey-zone" activity.

As such, many border security managers are now looking beyond the three traditional pillars (physical barriers, optical technology, patrols) and embracing smart alternatives such as RF (Radio Frequency) surveillance that incorporates automated features. 


RF spectrum monitoring and smart border control

National border security has historically focused on surveillance activities at ground level. However, the advent of drones (both in the air and maritime domains) is redefining the border control landscape. The autonomous nature of these self-driving vehicles renders them highly sophisticated yet inexpensive to deploy.  


This makes them a compelling proposition for transnational monitoring of difficult-to-reach areas or supporting search and rescue missions. Drones can even be configured to dynamically clear ground patrol vehicles that comply with certain parameters, thus streamlining the process for border transportation checkpoints. The drawback is that illegal drone usage is also becoming more prevalent, and border control staff need a reliable means to distinguish between the two.    


Effective RF spectrum monitoring empowers border control officers to recognize sanctioned and unsanctioned activity immediately. It also allows them to anticipate other potential incursions by detecting, identifying, and geolocating RF transmissions from different signal sources close to border perimeters.

Authorized drones can be quickly and reliably detected within an approved geofence with an accurate track-back to the operator. On the other hand, remote-piloted surface vehicles USVs can be monitored as they approach the shore to establish if they present security or operational risks. This type of proactive border monitoring offers the additional advantage of indicating the nature and severity of the threat based on the number and type of signals detected, including the ability to record and demodulate said signals. 

RF border surveillance offers a smart means to monitor

  • Hostile neighbors
  • Illegal migrant activity
  • Drug/firearm smuggling
  • Human trafficking
  • International terrorism
  • Transnational criminals
  • Grey Zone irregular activity 

The same technology also provides a reliable sub-system for maritime surveillance and port protection through augmented RF spectrum awareness. 

Radiofrequency (RF) surveillance systems in practice

As most incursions will involve wireless communication, the key challenge for border security personnel is determining the source and frequency ranges used. This holds particularly true for drones, which are often modified to hide in the noise. Any deployed RF surveillance system must therefore have the capacity to: 

  • Sweep the entire spectrum in real-time to proactively search for different RF transmissions
  • Seamlessly detect and classify these transmissions while dynamically geolocating signals of interest so appropriate counteraction can be taken
  • Use geofences to determine approved and unapproved geolocation of targeted signals
  • Provide 24/7 monitoring of all identified transmissions to understand trends and patterns through automated signal sampling and demodulation.

Deploying RF surveillance capabilities into an integrated smart border management system enables border forces to geolocate the source of all unrecognized RF transmissions accurately. Once the exact location has been ascertained, patrol teams can be mobilized to gather intelligence and quash illegal crossing attempts or trafficking activities. 

Creating an RF fence

Implementing a smart border surveillance system based on RF detection complements and increases the effectiveness of physical barriers. RF Sensors can be deployed quickly, cost-effectively, and at scale over vast borders, streamlining operations and augmenting first-line response capabilities.  

Developing an RF fence using wideband receivers gives a high probability of intercept across all monitored RF frequencies and an accurate line of bearing (LOB) or geolocation to the transmission source. Additionally, decoding and demodulation is used to listen into unencrypted push-to-talk communications. This, in turn, permits seamless identification and classification, thus determining likely threats and appropriate responses. 

RF solutions enhance the effectiveness of optical sensors. For example, an optical sensor with infrared capability can pick up a group of migrants but cannot separate the victims from the traffickers. RF sensors could geolocate the trafficker’s push-to-talk radios and discover not only the trafficker with the migrants but also a possible transport car waiting with its lights off on a street. Finally, the RF sensor could feed its data to the border monitoring C2 system that tasks the optical sensor to slew the car.  

Effective surveillance for challenging natural boundaries

Borders traversing high mountain ranges or along remote coastlines are particularly difficult environments to patrol manually because of their remoteness and sheer expanse. They also make perfect hiding points for illicit activities. Also, as 90% of international cargo is transported by ship, sea borders are particularly susceptible to organized crime and piracy. 

By exploiting the electromagnetic environment (EV) using RF border surveillance technology, border control teams can pre-empt hostile threats and illegal crossings by capturing and monitoring signal transmissions in real-time, thus heightening border security. Also, they can uncover other secondary transmissions from “dark ships” that turn off their AIS transponders. 

By strategically placing intelligent RF receivers along remote borders, it is possible to accurately monitor and analyze all signal activity 24/7—capturing vital intelligence that can be forwarded to command-and-control sensors. And with the necessary compute and backhaul connectivity built-in for real-time processing at the edge, sensitive border areas can be effectively monitored with minimal human involvement.  

Conclusion – smart borders are a must in an interconnected world

With cross-border criminals, covert state actors, terrorists, and human traffickers exploiting the latest wireless RF technologies for their benefit, RF border surveillance is imperative to modern border control, management, and national defense. As border security cannot afford downtime or interruption, RF spectrum monitoring tools must be incorporated into any integrated border management system to anticipate and prevent hostile activity. They offer insight into the invisible radio spectrum world in which adversaries and criminals are keen to exploit and operate within.  

Zac George

Zac George is the International Business Development Manager for CRFS. He is a former naval Electronic Warfare officer and also has experience in digital decoding. He speaks regularly on EW and spectrum topics globally, and lives in Switzerland.

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