What is the primary role of such stealth, low-supersonic UCAVs? SEAD operaritions against AD systems like the S400? @JamD @Quwa
in air warfare, technology is much more important than in land warfare. In contrast to the complexity of the land domain, the simplicity of its aerial counterpart offers fewer opportunities for cover and concealment, which in turn means that technology plays a more important role: staying airborne, avoiding detection, and escaping interceptions depend on technological capabilities.
IADS rely on multiple airborne and ground-based sensors and shooting platforms, including ground-based and airborne early warning radars, target acquisition radars, interceptor aircraft, and fixed and mobile short- and long-range air defense systems. The integration of data gathered by multiple types of sensors minimizes the probability that a target will be missed. Through multiple types of shooting platforms, IADS can engage different targets at both short and long ranges as well as at low and high altitudes.
A major strand that is overlooked is - range. In a conflict between Pakistan and India, the range matters significantly since both are next door, so reaction time can be seconds sometimes, the range at which modern radars can detect an incoming aircraft/UAV. Such range of detection affects the reaction time available for IADS to identify, locate, and engage an intruder after it has been detected. So for a stealth drone, if its stealth characteristics and the base from it took off, reduces the range of detection say from 130 km to 30 km, it will shift the balance towards its survival for the mission (it makes attacking easy), as 30 km might not leave sufficient time for air defenses to identify, locate, and engage a UAV.
A general concept is that the application of stealth technology to drones is aimed at reducing the range at which they can be detected, and the employment of drones in large enough numbers to saturate an enemy’s air defenses. So RCS is the first factor. A Bayraktar TB2 has a length of 6.5 m and a wingspan of 12 m, the US-made MQ-9A Reaper has a length of 11 m and a wingspan of 20 m, and the Iranian-made Shahed-129 has a length of 8 m and a wingspan of 16 m. In comparison, jet fighters such as the F-16 Fighting Falcon or F-18 Hornet are respectively 15 m and 17 m long, with wingspans of 9.5 m and 11.5 m. MALE UAVs are thus not much smaller than jet fighters, but they have a leaner shape compared to traditional crewed military aircraft, that their wingspan is not informative about their size, and in the near future, their wingspan will be much shorter.
The RCS of an object is not a function of solely its size; it is a function of the relationship between the wavelength of the radar pulse and the size of the target. In case of Indian IADS, radars operating at different wavelengths will produce different radar echoes when illuminating an incoming UAV, and whereas some of these echoes will be small, others will be quite significant. determinants of the RCS will be the overall shape and orientation of the UAV, not its size. The size of an object is not relevant for target acquisition and fire-control radars either, so a stealth drone has far better chances to penetrate enemy airspace than a non stealth drone. The S-400 is capable of detecting and tracking, at distance, objects with an RCS of 0.02 m^2.
Second detection issue is the the undercarriage missiles UAVs carry and their electro-optical (E/O) camera—which are significant sources of backscattering. To address this, in stealth UAV, missiles are stored internally and the E/O camera is shielded by a special radar-deflecting casing.
But for a stealth drone, is the smallest RCS frontal only ?
A UAV penetrating enemy territory will likely be illuminated from the front by radars searching for intrusion. IADS, however, relies on multiple ground-based and airborne radars providing overlapping coverage, which allow them to illuminate incoming vehicles from different directions; this is particularly relevant because the RCS of UAVs will vary quite significantly from different angles of incidence (both in azimuth and elevation).
The Comms (datalink) issue, small RCS of stealth UAVs tend to neglect that low observability to enemy sensors also requires radio silence or, basically radio-emission control. But UAVs need to receive and transmit information, primarily video footage that permits the ground station to carry out the intended operation. Such radio transmissions, in turn, can be detected and jammed.
Low altitude flying is debatable too, since flying at low altitude is effective only against ground-based radars, not against airborne radars such as AWACS on station in the air, as the elevation of the radar increases, so does its range of detection against low-flying aircraft, and the benefit of taking advantage of the curvature of the earth shrinks significantly and eventually vanishes. Then the concept of slow moving targets since slow-moving targets pose more of a problem for airborne radars oriented toward the ground than for ground-based radar oriented toward the sky, but pointing airborne(AWACS) radar at a downward angle that illuminates the horizon rather than the ground, so as to minimize the ground clutter reflection and to increase the chances of detecting an incoming threat. Signal processing and filtering also addresses the issue of detection from backgrounds like clutter. IAF also would have collected and stored the clutter of a given area, so its radar systems can more accurately disentangle a known unwanted return from an unknown but potentially relevant return in future iterations. Slow speed of drone exposes it to the variety of existing and unsophisticated air defense systems such as small arms, machine guns, antiair artillery, and MANPADs, in addition to the possibility of being engaged by patrolling aircraft.
India will deploy a layered defense system with long-range, middle-range, short-range, and man-portable air defense systems (LORAD, MEADS, SHORAD, and MANPADs), so drones flying at low altitude will be exposed to a variety of sensors and shooters that, individually or jointly, can detect, track, engage, and damage/destruct them well before they can get close to their target. In particular, IADS will cue antiair artillery toward an incoming UAV flying at low altitude, which will be targeted by anti-aircraft artillery (AAA) fire.
Altogether, stealth technology entails sacrificing technological unsophistication, but its leads to the escalation of the unit cost of the UAV. So the drone is not cheap anymore. Lets talk about radar-absorbing materials (RAMs). RAMs have electric properties such that when illuminated by enemy radar, they absorb part of the incoming electromagnetic wave; hence they attenuate the energy reflected by the aircraft, and thus reduce the range of detection and/or tracking. Even then, primary determinant of the RCS is the shape of a UAV.
The radar echo reduction resulting from the employment of RAMs varies significantly with radar frequency, polarization, and angle of incidence (azimuth and elevation). Thus it does not systematically reduce the chance of detection, tracking, and engagement by enemy air defenses, but it might reduce them only, maybe under some specific conditions. One might point out that a drone producer will likely employ RAMs that are particularly effective for fire-control radars, that is, those tasked with tracking and engaging an incoming threats (2.5–3.75 cm wavelength). RAMs do not shield prominent features that scatter incoming radar waves such as the undercarriage missiles, the E/O camera, and the engine of MALE UAVs. As a result, the savvy employment of RAMs will not reduce, either systematically or significantly, the vulnerability of MALE UAVs to detection and engagement. Same goes for RAM coating on JFT or J-10, if applied. For a UAV to absorb incoming radar waves, composite carbon fibers must have a peculiar internal structure, they need to display an internal angle that is attuned to the polarization of the incoming radar wave. S-400 gets an advantage as it employs circular polarization to counter this issue.
RAMs’ effectiveness is limited to only radar-guided systems, not against AAA guns that rely on infrared sensors and augmented visual sight as well as MANPADs that depend on infrared sensors or laser.
Stealth implies surprise. Surprise requires that enemy air defense systems do not have any information about the incoming UAV- its unique radar return, the structure and composition of its RAMs, or how its electronic countermeasures (ECM) work.
IADS rely on a virtually unlimited supply of cyber capabilities, EW jamming, high-power microwave shock systems, and soon in future - direct-energy weapons. Stealth UAVs will still be piloted through a line-of-sight (LOS) radio communication system (which makes Beyond-LOS mandatory for all Ops), these communications could be jammed by enemy EW capabilities. UAVs are vulnerable to cyberattacks and hacking, through which air defense systems can try to seize control of incoming enemy drones. In future, air defense systems can rely on microwave shock systems and direct-energy weapons but the down side is they require large amounts of energy to operate efficiently, and the laser beam capability (to damage and destroy targets) is limited by airborne dust and other factors.
The debate of saturation attack by UCAVs....
Traditional air defense systems are already capable of engaging a large number of incoming targets through AAA and SHORADs. MALE UAVs do not have any self-defense mechanism to deceive incoming missiles (such as chaff or flares), and given that their limited maneuverability constrains their ability to evade an incoming missile, the chances of survival when tracked by an engagement radar are reasonably low. This means that, even under conservative expectations, AAA guns or shoulder carried SAMs could shoot down a significant number of incoming UAVs. The IADs strengthens the defense’s capabilities to detect, track, and eventually engage incoming threats through different types of radars (ground/air) for early detection of swarm attack. To maintain their low cost and technological unsophistication the UAVs employed with swarming tactics will be subjected to hard tradeoffs, such as between range and payload and they cannot be replaced in massive numbers easily always as they are lost.
A MALE UCAV or stealth UCAV can penetrate enemy’s airspace, but against a country with IADS it becomes extremely difficult.