Analysis of the causes of the exhaustion of the physical resource of classic ground-based electronic warfare systems against new 32-element CRPA antennas and the technical rationale for creating a stratospheric electronic suppression echelon based on the modernized domestic An-196 drone or FP1.

During the latest combined strikes on Kyiv and Ukraine’s infrastructure nodes, air defense systems recorded a qualitative change in the behavior of Geran-type strike drones, including their jet-powered variants. Despite the high concentration of mobile and fixed electronic warfare systems along river valleys and at elevated points in cities, the drones are practically not deviating from their routes and are not losing contact with satellites. This creates the false impression that the defense system simply lacks enough stations or radiated power; in reality, we are dealing with a fundamental barrier of wave geometry and the mathematics of digital signal processing.

An engineering analysis of captured navigation modules from downed enemy drones demonstrates the completion of the adversary’s transition to 32-element digital adaptive CRPA antenna arrays. Each of the 32 microstrip elements of such an array records the phase shift and amplitude of the electromagnetic wave, while the built-in digital signal processor implements space-time adaptive processing (STAP) algorithms. By calculating the interference correlation matrix in real time, the processor forms weighting coefficients that create directions of deep spatial nulls of sensitivity (sensitivity dips of 40–50 dB) strictly in the directions of radiation from ground-based electronic warfare systems.

This mathematical selection is physically reinforced by the design of the aircraft itself. The CRPA antenna is mounted on the upper surface of the wing or fuselage and is pointed strictly toward the zenith, while from below it is fully shielded by a composite metal-containing material that reflects radiation from the ground surface. As a result, the drone becomes completely deaf to signals arriving from below or from low elevation angles, perceiving only the upper hemisphere.

Under these conditions, attempts to increase the number of ground transmitters become a dead-end path that harms one’s own defense. To mathematically overload the adaptive processor of a 32-element array, more than 15–20 independent uncorrelated jamming beams in each band (L1, L2, L5) from different azimuths must be directed at each drone simultaneously. During a group raid by several dozen drones, the simultaneous activation of such a number of ground-based electronic warfare systems causes a complete radio-electronic collapse of the rear area: surveillance radars are blinded, telemetry and missile guidance channels of air defense systems are blocked, and tactical VHF radio communications of mobile fire groups cease.

The way out of this dead end is dictated by the geometry of the antenna aperture itself: if the lower hemisphere is reliably blocked by shielding and STAP algorithms, then the upper hemisphere remains completely open. The drone’s antenna is obliged to “look” upward at large elevation angles, since that is where GNSS satellite signals come from. The power of satellite signals near the Earth’s surface is minuscule, amounting to about -130 dBm (fractions of a picowatt), so irradiating an enemy strike drone with a false signal from above inevitably leads to the failure of its global satellite navigation systems.

Placing the radiation source at altitudes of 10–12 kilometers, directly above the target flight area, makes it possible to transmit a synthesized signal at angles above +75° directly into the main lobe of the CRPA radiation pattern. The drone’s processor finds itself in a hopeless position: it is impossible to form a spatial null at the zenith, since this would cause immediate blinding and loss of signals from the entire operational GNSS constellation. If the processor does not cut out the zenith signal, the autopilot loops inevitably capture the imposed coherent false navigation field, making it possible to shift the drone’s space-time control grid and smoothly divert it kilometers away from the target.

Implementing this concept does not require the purchase of unattainable foreign high-altitude systems costing hundreds of millions of dollars (except in limited quantities for comparative testing). The optimal, economically justified, and mass-deployment-ready platform is the domestic long-range An-196 drone, developed with the participation of engineers from SE Antonov (the Liutyi program). Its composite airframe, with a basic wingspan of 6.7 meters, has high aerodynamic efficiency and, in its strike configuration, carries a 50–75 kg warhead over a range of more than 1,000 km. Removing the warhead frees up this entire mass reserve for specialized radio-electronic equipment, reinforced landing gear for repeated use, and additional fuel.

The main engineering task in adapting the An-196 Liutyi for high-altitude patrol is the modernization of the powerplant and wing. At an altitude of 10,000 meters, air density drops to ~0.41 kg/m³, causing a conventional atmospheric piston engine to lose up to three-quarters of its power, and the basic wing to lose lift. For prolonged loitering, the problem is solved by extending the wing panels (to 9–10 meters) and equipping the engine with a two-stage turbocharging system with a variable-pitch propeller, which forcibly maintains power and thrust in the rarefied atmosphere while preserving low fuel consumption. For high-speed high-altitude interception tasks, an option is possible with the installation of a small turbojet engine (TJE, compact class according to domestic design principles), with which the aircraft will reach the 9–10 km echelon and accelerate to 500 km/h, ensuring rapid entry into the duty zone and optimal loitering mission time. In a patrol turboprop/turbopiston configuration, the modernized An-196 gains the ability to stably maintain an operational ceiling of up to 9–10 km and loiter for hours in a designated square, providing reliable radio-electronic cover for a metropolis without the slightest risk to crews.

It is important to dispel the false notion of excessive mass and power consumption of the onboard electronic warfare complex. Since the high-altitude carrier is only 9–10 km from the target, an output RF power of just 20–40 W per band is sufficient to reliably suppress the extremely weak satellite signal (-130 dBm) at the drone antenna input. The entire digital section is built on commercial SDR modules USRP B205mini or B210 (Ettus Research / National Instruments) with Xilinx chips and AD9361 transceivers weighing less than 200 grams. Solid-state GaN amplifiers (Triad RF Systems) with efficiency above 50% and a 4–8-element patch AESA array measuring 30×30 cm consume only 300–400 W of electrical power, with a total system weight of 18–25 kg. The onboard generator of the modernized engine produces 1.2–1.5 kW, providing a twofold power reserve, taking into account the heating of air-pressure receivers.

The stratospheric navigation strike must be synchronized with the neutralization of the enemy drones’ backup guidance circuits. The disruption of satellite coordinates forces the optical terrain-correlation system (DSM-TC based on Rockchip RK3588 processors and Sony cameras) to search for visual landmarks, bringing the aircraft down to altitudes of 100–300 meters, where it automatically comes under concentrated fire from tube artillery and heavy machine guns of mobile groups. Simultaneous shutdown of cellular base stations along the flight corridor and the operation of mobile ground phase simulators destroy the cellular, MESH, and interferometric orientation subsystems of the swarm. Left without satellites and cellular radio beacons, the drone relies exclusively on its inertial unit, whose natural drift (1–3 km per hour) is guaranteed to divert the aircraft to a safe distance from the designated target.

Alongside the mass fleet of An-196 aircraft, an important niche remains in the system for the manned aircraft fleet of SE Antonov — the An-72/74 (practical ceiling 10,500–11,800 m, short-field takeoff) and the An-148 (ceiling 12,200 m, speed above 800 km/h). Thanks to the powerful onboard generators of the D-36 and D-436 cruise engines (as well as auxiliary power units), which generate tens of kilowatts of electrical power, these aircraft can carry heavy stations with numerous AESAs for wideband suppression in the infrequent case of massively large raids, and perform the functions of airborne command posts. However, the everyday line of sustained city defense must be held precisely by unmanned An-196 aircraft. At the same time, analysis of the flight performance characteristics of FP1-type UAVs records a significantly greater flight range compared with the current aircraft in the An line. This indicates the use of new modifications and aerodynamic solutions that ensure a substantial increase in continuous loitering time in the air.

One combat EW module based on USRP and GaN amplifiers costs only $25,000–50,000, while the total operating and fuel costs for a day of continuous duty by an An-196 flight element amount to only $3,500–5,000. By comparison, the launch of a single Patriot air defense missile costs $3–4 million, and NASAMS missiles cost about $1 million. Creating a permanent stratospheric barrier of six to nine An-196 UAVs over Kyiv (taking rotation and redundancy into account) requires less than $500,000, which turns the enemy drones’ expensive 32-element antennas into useless cargo and protects Ukraine’s critical infrastructure with maximum efficiency.

Ihor Akimov

Director of the Kronos Institute

Serhii Nedilko

serviceman of the Armed Forces of Ukraine, EW specialist, expert at the Kronos Institute

Institute for Social Dynamics and Security KRONOS

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