The range of threats today is quite broad, including medium-sized surveillance and attack aircraft, as well as small to micro drones. A portion of these small and medium aircraft are built for military applications, but recent conflicts have shown that commercial and consumer-facing civilian Uavs can be easily reconfigured to perform combat and combat support missions. The tactical UAV category (often referred to as the “Small Tactical UAV” (STUAS) category in the United States) has become particularly prevalent in recent conflicts, in part because of their low cost, high availability, and relative ease of use. In 2021, U.S. Marine Corps (USMC) General Kenneth McKenzie, then head of U.S. Central Command, described the proliferation of tactical drones as “the most concerning tactical development” since the rise of improvised explosive devices (IEDs) during the Iraq conflict. “I think what we’re seeing is the rise of a new component of war,” McKenzie said. His assessment sounds right. In intelligence, surveillance, targeting, and reconnaissance (ISTAR) roles, small to ultra-small Uavs can approach enemy formations with a relatively low risk of detection, provide information about troop movements or perform positioning, fire correction, and post-strike battle damage assessment for artillery. Electronic reconnaissance and offensive electronic warfare (EW) are additional tasks for Uavs. In an attack role, even Commercial off-the-shelf (COTS) hobbyist small Uavs can be configured to carry and release munitions over enemy forces or to act as wandering munitions (LM; Commonly known as “suicide drones” or “kamikaze drones”) carry explosives along the way. Such lunar modules can patrol specific areas until they find enough valuable targets of opportunity. They are then effectively transformed from surveillance drones to precision-guided munitions (PGMS).

Ukraine – the greatest drone war

The conflicts of the past two decades have highlighted the growing role of drones in armed forces around the globe. The dramatic impact of temporarily reconfigured COTS systems was first fully demonstrated a decade ago during the ISIS/Daesh insurgency in Iraq (although various other irregular forces discovered their utility around the same time). The ongoing war in Ukraine has reached a new intensity, with drones and artillery being one of the most important weapon systems deployed on the battlefield. Tens of thousands of drones have been launched over the past two years, making this an unprecedented drone war. Fixed-wing, Global Navigation Satellite System (GNSS) and inertial navigation system (INS) guided medium UAS, such as the Iranian Shahed 131 and 136, can strike fixed infrastructure targets, And those equipped with photoelectric infrared (IR) sensors – such as Turkey’s Bayraktar TB2 – can target mobile military vehicles with guided bombs and missiles. Ukraine’s home-made AQ 400 Kosa UAV has enough range to reach Moscow with a payload of 32 kg and a shorter distance with a payload of 65 kg. Kyiv plans to increase production to 500 vehicles a month. A much larger number of smaller drones target soldiers in foxholes and trenches, where they are largely protected from other battlefield threats. The modified COTS-based quadcopters can attack as single units or clusters, and are also capable of destroying armored vehicles and even main battle tanks (MBTS). Many small Uavs are radio-controlled via radio frequency (RF) links. This includes so-called first-person view (FPV) drones, which can effectively act as temporary LMS – on-board cameras provide operators with a view of the pilot, enabling very precise target decisions, even allowing the aircraft to fly past doorways or into open vehicle hatches. Notably, RF-controlled UAV operation does not require extensive training; COTS systems are designed to be easy to use, and any country where the adolescent population grew up playing video games will have a large number of potential pilots. More advanced aircraft are often built specifically for the military, and they use GNSS and/or INS to perform preprogrammed reconnaissance or strike missions with minimal direct supervision. Since the onboard database allows active identification of legitimate targets, some lunar modules can display target autonomy. They can attack even if the radio link with the control station is jammed.

C-UAV and C-RAM requirements
Traditional missile-based air defense systems are well suited to shoot down larger to medium, complex military Uavs and larger ranges of LMS, such as the Shaheed family. However, they are not a viable option for anti-Uavs against small UAV threats. Even if the latter can be detected in the engagement zone of an ultra-Short range air defense/Short range Air defense (VSHORAD/SHORAD) system, their heavy use capability will quickly deplete (V)SHORAD magazines, thus leaving protected units vulnerable to more advanced aircraft or missiles. The cost asymmetry also makes conventional air defense systems an economically unsustainable solution to such threats. To get a sense of the extent of this asymmetry, CBS News reported in May 2023 that a single FIM-92 Stinger series missile costs more than $400,000. Typical off-the-shelf small drones, such as the DJI quadcopter, cost just a few hundred dollars. To date, RFI remains the most widespread (and arguably most effective) weapon against small Uavs. Rfi works by disrupting the aircraft’s navigation and control systems, either by preventing the reception of command signals from the control station, or by blocking satellite navigation frequencies to disrupt GNSS guidance. Depending on the strength of the jamming system, the effect can be scaled in terms of intensity as well as the width and depth of the target airspace. Both sides in Ukraine have deployed extensive jamming to protect their positions from enemy aircraft and to suppress the capabilities of enemy drones prior to offensive operations. Powerful EW systems can be mounted at fixed locations or on vehicles for easy retargeting. Low echelon tactical units were equipped with portable jammers, while tanks and other vehicles were photographed with jammers on top of their turrets. However, EW based countermeasures also have some weaknesses. Frequency hopping is usually a simple and effective way to circumvent RFI. Moreover, as demonstrated by Ukrainian attacks on Russian EW sites, jammers’ signals can be triangulated so that they can be located and targeted by artillery, air-launched bombs, or missile strikes. Increased autonomy and the introduction of redundant navigation systems are expected to reduce the impact of future RFI, but this is not absolute. Some Uavs will continue to rely on RF data links for remote control, receiving mission updates, or forwarding situational awareness data back to the operator. Even if additional anti-jamming navigation systems become more common, GNSS will remain an important navigation tool. Even if the disturbance does not completely disable vehicle control or navigation, it may still have a negative impact on the effectiveness of the UAV. Ew technology is expected to continue to evolve, increasing signal strength, range, and effectiveness, and using smaller portions of the electromagnetic spectrum to minimize collateral effects on friendly systems. The Pentagon plans to deploy jamming capabilities regularly in the lower echelons, particularly at the platoon level, and is already experimenting with EW systems mounted on light infantry vehicles, such as the MRZR of the US Marine Corps. Other armed forces are taking a similar approach. Improved jamming alone cannot offset the expected enhancement of tactical UAV capabilities and operational concepts. Other kinetic techniques are being actively pursued. Some of these measures can also protect ground forces and facilities from rocket, artillery and mortar (RAM) attacks. Such a C-RAM system can have a large degree of functional overlap with the C-UAV role, thus making a system capable of performing both missions an attractive proposal.