Anti-drone systems for low-slow-small (LSS) targets primarily consist of two main parts: detection and countermeasures. Drone detection technologies can be categorized into spectrum detection and drone radar detection. As for countermeasure technologies, there are more technical approaches, such as suppression jamming, spoofing jamming, physical destruction, and direct capture, among others. However, regardless of the approach, suppression and spoofing jamming are always included, as radio frequency suppression and spoofing jamming are the fastest, most effective, and lowest-cost technical means for countering LSS drones. The following sections briefly introduce these technologies.
Suppression Drone Jamming
As mentioned, suppression jamming is perhaps the most direct, effective, and lowest-cost countermeasure method for LSS drones. Suppression countermeasures essentially involve using radio frequency jamming against the remote-control links, data transmission links, and GPS navigation signals of the illegal drone, rendering it blind, deaf, and mute within a certain area. Even when equipped with an inertial navigation system, the drone can only maintain its original attitude for an extremely short period and cannot continue flying as the operator intended.
Typically, consumer-grade LSS drones use wireless data links operating in 2-3 common frequency bands: 2.4GHz, 5.8GHz, and 915MHz. These three bands are often the main frequencies used by consumer-grade illegal drones. For professional-grade drones, the dedicated data link bands are 845MHz and 1.4GHz, which are rarely used by general consumer drones. Common countermeasure jammers primarily focus on the 2.4GHz, 5.8GHz, and 915MHz bands.
In principle, if the suppression signal is sufficiently powerful and covers the relevant satellite navigation frequencies, the drone will lose its autonomous navigation capability.
As this analysis shows, suppression-based drone countermeasures are not technically complex. Since the frequencies of the communication data links and signals frequencies are public, generating a signal (even a noise signal) with the same frequency and sufficient strength can achieve the suppression effect. In short, this countermeasure is the simplest, most direct, and most effective solution.
Besides consumer-grade LSS systems, this simple suppression method is also effective against some professional-grade drones, even military-grade drones, but it requires higher transmission power.
Spoofing Drone Jamming Systems
Compared to suppression jamming countermeasure systems, spoofing or decoy countermeasure systems are more technically sophisticated. Spoofing countermeasures consist of two main parts: data link spoofing and navigation signal spoofing.
Data link spoofing is relatively difficult. First, the target drone’s data link must be detected and analyzed. If parameters such as frequency, bandwidth, modulation method, and communication protocol of the entire data link can be deciphered, it means complete takeover of the illegally intruding drone can be achieved. This task is quite challenging, especially for frequency-hopping communications and data links using various encryption technologies.
Physical Countermeasures
Physical countermeasure systems, simply put, involve direct destruction or capture. The two primary methods are net-based interdiction, which entangles the drone, and high-energy laser neutralization, which thermally disables critical components.
Technological Innovations and Prospects
To address the security risks posed by drone misuse, counter-drone technologies have evolved in a multi-layered system encompassing detection, jamming, control, and destruction. From cost-effective suppression jamming to technically complex spoofing and decoy methods, and further to direct physical destruction, different technical means have their own focuses, collectively building a comprehensive defense capability against LSS and professional-grade drone systems. In the future, as drone performance continues to evolve and application scenarios expand, countermeasure systems will need to continuously improve in terms of precision, adaptability, and multi-target engagement capabilities, while further refining regulations and operational protocols to achieve an effective balance between security control and airspace order.