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Active protection system

An active protection system (APS) is a defensive technology designed to detect, track, and neutralize incoming threats—such as rocket-propelled grenades (RPGs), anti-tank guided missiles (ATGMs), and other anti-armor munitions—before they impact a protected military vehicle, thereby enhancing survivability beyond traditional passive armor.^[1] These systems operate on a "left-of-boom" principle, intercepting threats in flight using sensors, processing units, and effectors, and are typically integrated into armored platforms like tanks, infantry fighting vehicles, and personnel carriers.^[2] APS represent a critical evolution in vehicle protection, addressing the limitations of armor against modern, high-velocity threats in urban and asymmetric warfare environments.^[3] APS are broadly categorized into three types based on their neutralization methods: hard-kill, soft-kill, and hybrid systems. Hard-kill APS physically destroy incoming threats using explosive projectiles, fragmentation charges, or directed energy, with notable examples including Rafael's Trophy, which employs radar-guided interceptors to counter ATGMs and RPGs, and Elbit Systems' Iron Fist, which uses shockwave-based effectors for close-range defense.^[2] Soft-kill systems disrupt threats electronically or optically without direct destruction, such as through laser jamming, smoke obscurants, or infrared countermeasures, as seen in Hensoldt's MUSS 2.0 for the Puma infantry fighting vehicle.^[1] Hybrid systems combine both approaches for broader threat coverage, like Rheinmetall's StrikeShield, which integrates hard-kill munitions with soft-kill diversions and has been selected for Hungary's Lynx KF41 vehicles.^[2] The development of APS traces back to the late 1990s, driven by escalating threats from portable anti-armor weapons, with early efforts in Russia (e.g., Arena), the United States, Germany, and Israel.^[2] In the U.S., the Army and Marine Corps have pursued APS integration since the early 2000s to meet Future Combat Systems requirements, focusing on modularity for vehicles like the M1 Abrams and Stryker, though initial programs like Raytheon's Quick Kill faced challenges and were canceled.^[4] Israel's Trophy achieved operational maturity in 2009 and has seen combat success, protecting Merkava tanks in Gaza and leading to exports, including U.S. adoption for Abrams upgrades in 2021.^[1] Recent advancements, spurred by conflicts like Ukraine, include drone countermeasures and reduced collateral damage features, with global deployments expanding to platforms from Russia's T-72B3M to China's Type 99A tank by 2025.^[2] Key challenges in APS implementation include high costs (e.g., up to $600,000 per unit for South Korea's KAPS), integration with existing armor without compromising mobility, and minimizing risks to nearby infantry from hard-kill effectors.^[2] Despite these, APS have proven effective in real-world scenarios, such as Turkey's PULAT system on M-60T tanks in Syria since 2018, underscoring their role in modern armored warfare.^[2] Ongoing programs, like the U.S. Modular Active Protection System (MAPS), aim to standardize APS for rapid fielding across multiple vehicle types.^[4]

Introduction

Definition and Purpose

An active protection system (APS) is an onboard defensive technology integrated into military armored vehicles that detects, tracks, and neutralizes incoming threats, such as anti-tank guided missiles (ATGMs), rocket-propelled grenades (RPGs), before they strike the protected platform.^[4]^[3] These systems operate as a "hit-avoidance" mechanism, intercepting or diverting projectiles in real time to prevent physical contact and damage.^[1]^[3] The primary purpose of an APS is to significantly enhance the survivability of armored vehicles in high-threat combat environments by serving as a last-line defense that complements rather than replaces traditional armor.^[4]^[1] By neutralizing threats proactively, APS reduces potential losses to vehicle crews and assets, addressing vulnerabilities exposed by advanced anti-armor weapons that can penetrate conventional passive defenses.^[3] This capability is particularly vital in asymmetric warfare scenarios where threats like ATGMs and RPGs proliferate.^[4] At a high level, APS typically comprises three core components: sensors for threat detection and tracking, such as radar or optical systems; processors that assess and prioritize threats; and effectors that deploy countermeasures to engage the incoming projectile.^[4]^[3] Unlike passive armor, which relies on static absorption of impacts, or reactive armor that activates only upon contact, APS intervenes dynamically during the threat's approach, enabling preemptive neutralization.^[1]^[4] Broadly, these systems fall into soft-kill categories that disrupt threats non-destructively and hard-kill categories that physically destroy them.^[1] The basic operational cycle of an APS involves rapid detection of an incoming threat, identification to confirm its danger, and immediate response through countermeasure deployment, all occurring within milliseconds to outpace the projectile's trajectory.^[4]^[3] This sequence ensures the system's autonomy in high-stress conditions, minimizing reliance on human intervention.^[1]

Historical Development

The origins of active protection systems (APS) trace back to the 1970s in the Soviet Union, where the need to counter rocket-propelled grenade (RPG) threats in potential Cold War tank engagements drove early development. The Drozd system emerged as the first prototype in 1978, designed by the Tula KBP Instrument Design Bureau to provide hard-kill interception against incoming projectiles using radar detection and explosive countermeasures. This initiative responded to vulnerabilities exposed in armored warfare doctrines, marking the initial shift from passive armor to active defenses.^[5] During the 1980s and 1990s, advancements accelerated amid escalating regional conflicts and arms races. In Russia, the Arena system was developed in the 1980s, introducing millimeter-wave radar for 360-degree detection and fragmentation warheads to neutralize anti-tank guided missiles (ATGMs), with initial testing on T-72 tanks. Israel began APS research in the late 1990s, motivated by asymmetric threats from Hezbollah and Hamas, leading to conceptual studies for vehicle-mounted interceptors. Concurrently, the U.S. Army initiated exploratory efforts in the early 1980s, focusing on sensor fusion and countermeasure technologies to protect against ATGMs, though programs remained in technology demonstration phases without widespread fielding.^[6]^[2] The 2000s saw proliferation following combat lessons, particularly the 2006 Lebanon War, where Israeli Merkava tanks suffered significant ATGMs and RPG losses, prompting accelerated Trophy APS development by Rafael Advanced Defense Systems. Operational testing of Trophy began shortly after, with full integration into Merkava Mk4 tanks achieved in 2009, and the first confirmed interception of an ATGM occurring in March 2011.^[7] In the 2010s and 2020s, APS matured with broader adoption, integrating into networked warfare platforms. NATO forces advanced implementations, for example, the U.S. Army's adoption of the Israeli-developed Trophy APS for M1 Abrams tanks starting in 2021.^[1] Russia deployed upgraded Arena-M systems on T-90M and T-80BVM tanks during the Ukraine conflict starting in 2022, addressing top-attack threats from drones and ATGMs. The U.S. Army's Modular Active Protection System (MAPS) program, launched in 2015 and spanning five years, produced prototypes like Iron Curtain, emphasizing modular hard-kill effectors for Stryker and Abrams vehicles. These evolutions were propelled by real-world lessons, including IED and ATGM vulnerabilities in Iraq and Afghanistan operations, as well as heavy Syrian tank attrition from precision-guided munitions, fostering integration with battle management systems for multi-threat response.^[8]^[1]^[9] As of 2024, the APS market was valued at approximately USD 4.42 billion, fueled by AI-enhanced detection algorithms and rising drone swarm threats in peer conflicts, as evidenced by industry analyses projecting continued expansion through platform retrofits and exports.^[10]

Classification

Soft-Kill Systems

Soft-kill active protection systems utilize non-destructive countermeasures to disrupt or mislead the guidance mechanisms of incoming threats, such as wire-guided or laser-guided anti-tank guided missiles (ATGMs), thereby causing them to veer off course without direct physical interception. These systems detect threats via onboard sensors and respond by employing electronic, optical, or aerosol-based effectors to confuse the projectile's seeker or command link, exploiting vulnerabilities in guidance technologies like semi-automatic command to line of sight (SACLOS) or semi-active laser (SAL) homing.^[11]^[1] Key technologies in soft-kill systems encompass infrared (IR) jammers that emit modulated IR signals to seduce or blind missile seekers, multispectral aerosols or smoke screens that obscure the target's signature across multiple wavelengths, laser dazzlers that overload optical and IR sensors to induce temporary blindness, and radio frequency (RF) jamming to interfere with radar-guided threats. For instance, IR jammers like those in the Shtora-1 system generate pulsed emissions to mask the vehicle's IR profile and disrupt SACLOS tracking flares. Laser dazzlers, such as the JD-3, direct high-energy beams to saturate guidance optics, while smoke dispensers deploy rapidly forming obscurants effective up to 50-70 meters in under 3 seconds.^[11]^[12] These systems offer distinct advantages, including reduced collateral damage risk from non-kinetic engagement, reusability without frequent resupply in electronic variants, and lower overall system weight—65-170 kg depending on configuration and version, such as under 60 kg for MUSS 2.0—enhancing vehicle mobility compared to kinetic alternatives. They prove particularly suitable for countering legacy unguided munitions or simple-guided threats like RPGs, where physical destruction is unnecessary, and their implementation costs are generally lower due to minimal expendables and simpler integration.^[1]^[11]^[13] Effectiveness is evidenced by test results showing significant reductions in hit probabilities against ATGMs, as with Shtora-1's disruption of systems like TOW and MILAN. Advanced iterations, including MUSS 2.0, achieve success against RPGs and top-attack munitions through improved sensor fusion and multi-spectral jamming, with over 350 units deployed operationally demonstrating reliability in real-world conditions as of 2024. Limitations persist against non-line-of-sight or highly advanced seekers, confining efficacy to visible-range engagements.^[1]^[11]^[14] Integration often pairs soft-kill effectors with existing vehicle smoke launchers for layered obscuration or incorporates aircraft-derived Directed Infrared Countermeasures (DIRCM) adapted for ground platforms, such as BAE Systems' vehicle-mounted variants, to provide 360-degree coverage against IR-guided threats. This modular approach allows seamless addition to medium and heavy armored vehicles without major redesigns.^[15]^[1]

Hard-Kill Systems

Hard-kill systems employ destructive countermeasures that physically intercept and eliminate incoming threats, such as anti-tank guided missiles (ATGMs) and rocket-propelled grenades (RPGs), by launching explosive projectiles or fragments designed to collide with and detonate upon the munitions mid-flight.^[4] This mechanism relies on automated detection and rapid response to neutralize the threat before it reaches the protected vehicle, ensuring the countermeasure detonates at a safe distance to prevent damage to the platform.^[11] Key technologies in hard-kill systems include radar-guided launchers that fire high-velocity fragments or interceptors to achieve quick engagement times against threats approaching at speeds up to 1200 m/s.^[16]^[17] Vertically launched countermeasures provide 360-degree coverage, allowing interception from any direction, while multi-hit capabilities enable the system to handle salvos of multiple threats in sequence.^[18] These systems offer significant advantages in countering high-speed threats like ATGMs, with reported intercept rates of 90-100% in controlled tests, and they effectively manage top-attack profiles where threats approach from above.^[4] Their physical destruction approach provides reliable defeat of kinetic and explosive warheads that soft-kill methods may not fully neutralize. However, hard-kill systems pose risks of collateral damage to nearby infantry or friendly forces due to the explosive nature of interceptors, and they typically carry limited ammunition, with 4-12 rounds per engagement depending on configuration.^[4] Additionally, they demand higher power and weight requirements, often 200-500 kg for the full system, which can strain vehicle integration on lighter platforms.^[19] Variants of hard-kill systems include close-in types operating at 0-50 m ranges, optimized for short-range threats like RPGs, and medium-range versions extending to 100 m, suitable for faster-moving missiles such as ATGMs.^[11] Hard-kill approaches can complement soft-kill systems for broader threat mitigation.^[8]

Hybrid Systems

Hybrid active protection systems combine soft-kill and hard-kill countermeasures to provide layered defense against a wider spectrum of threats, leveraging non-destructive disruption for initial response and kinetic interception as needed. These systems integrate sensors for threat classification and select the appropriate effector, enhancing overall effectiveness while mitigating limitations of individual approaches. Notable examples include Rheinmetall's StrikeShield, which pairs hard-kill munitions with soft-kill diversions like multispectral smoke and jamming, selected for integration on Hungary's Lynx KF41 vehicles as of 2023.^[2]^[1]

Operational Principles

Detection and Tracking

Active protection systems (APS) rely on advanced sensor suites to detect and track incoming threats, such as anti-tank guided missiles (ATGMs) and rocket-propelled grenades (RPGs), in real time. These systems typically employ multi-sensor fusion, integrating millimeter-wave radar for precise velocity and direction measurements, electro-optical/infrared (EO/IR) sensors for seeker head detection and visual confirmation, and acoustic sensors for identifying low-velocity threats like mortar rounds or small drones. Millimeter-wave radars, operating in high-frequency bands, provide all-weather, 360-degree coverage with short-range detection capabilities up to several hundred meters, enabling rapid threat identification even in obscured environments. EO/IR sensors complement radar by offering high-resolution imaging in the visible and infrared spectra to distinguish threat signatures from environmental clutter, while acoustic vector sensors detect subtle sound profiles of approaching projectiles at close ranges.^[20]^[21] Threat classification in APS involves sophisticated algorithms that discriminate genuine threats from non-lethal objects like birds or debris. These algorithms analyze Doppler shifts in radar returns to assess speed and trajectory, combined with signature matching against known threat profiles from EO/IR and acoustic data. Multi-sensor fusion enhances reliability by cross-validating data streams, reducing erroneous activations and prioritizing high-risk threats based on velocity thresholds (e.g., 50-300 m/s for typical ATGMs). This process ensures only validated threats proceed to tracking, minimizing unnecessary resource expenditure.^[22]^[23] Once detected and classified, the tracking phase employs real-time kinematic estimation to predict threat trajectories. Kalman filtering algorithms are widely used for this purpose, fusing sensor measurements to estimate position, velocity, and acceleration while accounting for noise and vehicle motion, enabling accurate interception point predictions within milliseconds. Engagement envelopes are typically defined at slant ranges of 10-100 meters, balancing detection lead time with countermeasure effectiveness; for instance, threats are engaged around 10 meters to ensure safe neutralization without collateral risk to nearby forces. These filters iteratively refine predictions, supporting both soft-kill responses like jamming (via EO/IR cueing) and hard-kill interceptions (via radar-guided effectors).^[24]^[25] APS sensor and processing components are designed with low size, weight, and power (SWaP) constraints to facilitate integration on armored vehicles without compromising mobility or payload capacity. For instance, Elbit's Iron Fist weighs approximately 250 kg and has low power consumption, using compact, solid-state electronics for rugged mounting on turrets or hulls. Networked modes allow data sharing across vehicle platoons via tactical links, enabling cooperative detection where one unit's sensors cue others, extending collective situational awareness against salvos or swarming threats.^[26] As of 2025, advancements in artificial intelligence and machine learning (AI/ML) have introduced adaptive learning capabilities to APS detection and tracking. These algorithms analyze post-engagement data to refine threat models in real time, improving accuracy against evolving threats like hypersonic fragments from advanced warheads by dynamically adjusting Doppler and signature thresholds. Recent upgrades, such as the October 2024 enhancement to Rafael's Trophy for top-attack interception of drones and loitering munitions, further improve overhead threat detection using advanced sensor fusion. AI-driven fusion reduces latency in multi-sensor processing, enhancing overall system resilience in contested environments.^[27]^[28]

Countermeasure Deployment

Once a threat is detected and tracked, active protection systems (APS) initiate rapid decision-making processes to deploy countermeasures, typically within milliseconds to ensure interception before impact. Fire-control computers process sensor data through automated decision loops, evaluating threat trajectories and validity in timelines ranging from 50-200 milliseconds from detection to countermeasure launch, allowing systems like Rheinmetall's to respond in as little as 560 microseconds for certain effectors.^[29]^[1] These loops incorporate abort logic to cancel deployments against non-threats, such as errant projectiles or decoys, preserving limited effectors; for instance, Rafael's Trophy system refrains from firing if an incoming missile deviates sufficiently to miss the vehicle.^[30]^[1] Deployment methods vary by APS type, with soft-kill systems using directional emitters to disrupt threat guidance without physical destruction. These include infrared jammers, laser dazzlers emitting pulses at 1-10 kW to blind or confuse sensors on incoming projectiles, and smoke screens for visual obscuration, all directed precisely toward the threat vector to minimize energy waste.^[31]^[1] Hard-kill systems, in contrast, employ pyrotechnic launchers to propel interceptor warheads—such as explosively formed penetrators (EFPs) or fragmentation grenades—that detonate near the threat to neutralize it kinetically; electromagnetic launchers, as conceptualized in systems like Artis' Iron Curtain, accelerate projectiles at high speeds for similar effects, though most operational variants rely on explosive propulsion for reliability.^[32]^[2] Examples include Elbit's Iron Fist, which launches explosive projectiles from trainable tubes, and Rafael's Trophy, utilizing rotating launchers with EFPs for precise engagement.^[1] To achieve comprehensive defense, APS provide 360° azimuthal coverage through either rotating effectors that scan the perimeter or distributed static arrays mounted around the vehicle, enabling simultaneous handling of multiple threats from any direction. Systems like Trophy employ four radar-integrated panels for hemispheric protection, while distributed designs such as Rheinmetall's StrikeShield use fixed blast effectors for all-around response without mechanical rotation.^[2]^[1] In ambiguous scenarios, such as cluttered urban environments, operators can invoke manual override via integrated interfaces to confirm or abort automated decisions, ensuring human judgment supplements algorithmic processing.^[33] Safety protocols are integral to countermeasure deployment, prioritizing avoidance of collateral damage to nearby allies or dismounted infantry. Fragile ally detection algorithms, often leveraging IFF (Identification Friend or Foe) transponders or multi-spectral sensors, inhibit launches if friendly forces are within the engagement zone; for example, systems like Iron Fist and AKKOR minimize fragment dispersion to reduce risks to surrounding personnel.^[2] Self-test cycles occur automatically during vehicle startup, verifying sensor alignment, effector functionality, and decision logic without expending munitions, thereby confirming operational readiness before mission commencement.^[32] Integration with the host vehicle's systems enhances deployment efficiency, with APS often cued by shared fire-control radars originally designed for main gun targeting. On platforms like the M1 Abrams or Merkava, Trophy integrates with the vehicle's fire control and situational awareness systems, utilizing its dedicated radar panels for threat detection and interception guidance. This shared architecture reduces latency and power demands, allowing seamless operation during high-maneuver scenarios.^[34]^[2]^[35]

Challenges and Limitations

Environmental Factors

Active protection systems (APS) rely on sensors such as electro-optical/infrared (EO/IR) and radar for threat detection, but adverse weather conditions can significantly impair their performance. Rain and fog attenuate EO/IR signals, reducing detection accuracy by scattering light and cooling thermal contrasts between targets and backgrounds, with fog particularly affecting visible and near-IR wavelengths more severely than far-IR systems. Heavy precipitation can also cause radar signal attenuation, especially in millimeter-wave bands used by many APS, leading to reduced range and resolution in detecting incoming threats. Dust and sand storms exacerbate these issues by causing abrasion on sensor optics and housings, potentially clogging mechanisms and degrading long-term sensor integrity.^[36]^[37]^[38] Terrain variations further challenge APS reliability, particularly in complex environments. Urban settings introduce clutter from buildings, vehicles, and wires, which can overwhelm radar sensors and increase false positive rates by mimicking threat signatures, complicating threat discrimination. Off-road or rough terrain induces vibrations that may misalign sensors, affecting tracking precision; however, gyro-stabilization mechanisms in modern APS mitigate this by maintaining sensor orientation during vehicle motion. These environmental interactions can overlap with advanced threat clutter, amplifying detection errors in contested areas.^[39]^[40] Temperature extremes pose risks to APS components, with operational ranges typically specified from -40°C to +60°C to ensure functionality in diverse climates. High temperatures accelerate battery degradation and electronic component failure, reducing power output and reliability, often necessitating active cooling systems to dissipate heat from processors and launchers. Low temperatures can stiffen materials and impair sensor response times, though insulated designs help maintain performance. Electromagnetic interference (EMI) from adversarial jamming or onboard vehicle emissions can overload radar and EO/IR sensors, disrupting signal processing; countermeasures such as frequency hopping enhance resilience by rapidly changing operating frequencies to evade interference.^[41]^[42]^[43] To address these factors, APS undergo rigorous environmental testing aligned with NATO STANAG 4370 protocols, which standardize evaluations for defense materiel under allied environmental conditions. These include salt fog exposure to assess corrosion resistance on sensors and housings, as well as shock and vibration tests to simulate operational stresses, ensuring systems withstand abrasion, thermal cycling, and mechanical impacts without performance loss.^[44]

Advanced Threat Vulnerabilities

Top-attack munitions represent a significant vulnerability for many active protection systems (APS), as they utilize tandem warheads and steep downward trajectories to strike the thinner upper armor of vehicles, often bypassing side- or turret-mounted sensors optimized for horizontal threats. The FGM-148 Javelin missile, for example, employs an arched top-attack profile that reaches a peak altitude of 150 meters before descending, exploiting gaps in vertical coverage common to earlier APS designs.^[45]^[46] Addressing this requires enhanced overhead sensor and interceptor integration, as demonstrated in upgrades to systems like Rafael's Trophy APS, which now incorporate 360-degree radar and effectors for top-attack interception.^[47] Newer developments, such as South Korea's KAPS, aim to provide comprehensive hemispheric protection against such trajectories through advanced radar architectures.^[2] Salvo attacks, involving the coordinated launch of multiple threats such as 2-4 rocket-propelled grenades (RPGs) or anti-tank guided missiles, can overwhelm APS by depleting limited interceptor ammunition or saturating processing capabilities, leading to incomplete neutralization. These saturation tactics have been prominently observed in the Ukraine conflict from 2022 to 2025, where low-cost, massed munitions like FPV drones and RPGs have forced APS-equipped vehicles into vulnerable positions by exceeding system response limits.^[1]^[48] In such scenarios, even hard-kill APS with finite magazines—typically holding 10-20 rounds—struggle against volleys that prioritize quantity over individual sophistication.^[49] Low- or no-signature threats further complicate APS effectiveness by minimizing detectability across radar, infrared, and other spectra. Stealthy drones engineered with radar cross-sections (RCS) below 0.01 m², achieved through advanced materials and shaping, evade traditional radar-based detection in APS, while optical camouflage reduces infrared signatures to challenge thermal sensors.^[50] Potential future threats, such as hypersonic projectiles exceeding Mach 5, could further compress reaction times, though current APS tracking algorithms are designed for slower, predictable threats like ATGMs. Russian APS deployments in Ukraine, for instance, have shown radar limitations against low-visibility micro-drones, highlighting how such threats can penetrate defenses undetected. Adversaries increasingly deploy counter-APS measures to exploit these weaknesses, including decoys that mimic incoming threats to exhaust resources and anti-radiation missiles (ARMs) targeted at APS radar emitters. Active decoys, which replicate the radar returns of real munitions, can confuse detection systems and force premature interceptions, as analyzed in studies on theater missile defense countermeasures.^[51] ARMs like the AGM-88 HARM home in on APS radar emissions, potentially disabling the system before it engages, with defensive aids such as intermittent radiation or towed decoys offering partial mitigation but not full immunity.^[52] Emerging mitigation trends focus on hybrid APS architectures for broader threat coverage. These networked systems improve response to top-attacks and salvos through enhanced sensor fusion.^[1] However, simulations against advanced threats underscore ongoing challenges in achieving high success rates, demanding proactive adaptations in sensor fusion and resource allocation. While environmental clutter can baseline detection challenges, these adversarial innovations demand proactive adaptations in sensor fusion and resource allocation.^[1]

Examples and Deployments

Systems by Country

Israel has been a pioneer in active protection systems (APS), driven by the need to counter asymmetric threats in urban environments, particularly anti-tank guided missiles (ATGMs) and rocket-propelled grenades (RPGs) prevalent in regional conflicts. The Trophy APS, developed by Rafael Advanced Defense Systems, debuted in 2009 and was first fielded on the Merkava Mark 4 main battle tanks of the Israel Defense Forces (IDF), providing 360-degree hard-kill protection by intercepting incoming projectiles with explosively formed penetrators.^[53] This system has since been integrated onto U.S. M1 Abrams tanks supplied to Israel, enhancing interoperability in joint operations. Complementing Trophy, the Iron Fist APS, originally developed by Israel Military Industries (now part of Elbit Systems), is designed for lighter armored vehicles such as the Eitan APC, offering modular hard-kill capabilities with low weight and power requirements suitable for urban maneuverability.^[54]^[55] Russia emphasizes APS integration on mass-produced tanks to defend against NATO ATGMs and similar threats in high-intensity scenarios. The Arena-M, an upgraded version of the original Arena system developed by the Kolomna-based KBM Engineering Design Bureau in the 2010s, equips T-90M and T-72B3M tanks with radar-guided interceptors that neutralize incoming projectiles up to 50 meters away, focusing on top-attack munitions.^[56]^[57] Russia's Shtora-1 serves as a soft-kill hybrid complement, using infrared jammers and laser warning receivers to disrupt semi-active laser-guided ATGMs on platforms like the T-90, though it lacks hard-kill interception.^[58] The United States has pursued APS development to address evolving threats, including improvised explosive devices (IEDs) and ATGMs in counterinsurgency and peer conflicts, with a focus on modular architectures for rapid integration across vehicle fleets. The Modular Active Protection System (MAPS), initiated in 2014 by the U.S. Army Combat Capabilities Development Command, provides an open-system framework for sensors and effectors, with prototypes tested on Stryker vehicles in the 2020s to enable layered defenses.^[59]^[60] Artis LLC's Iron Curtain, a hard-kill APS using linear formed penetrators, underwent government testing for Stryker integration in the early 2020s but was not selected for full qualification.^[61] In parallel, the U.S. Army began integrating Rafael's Trophy APS on M1A2 Abrams tanks starting in 2023, achieving full Modular APS Framework 2.0 compliance by 2025 for enhanced counter-rocket, artillery, and mortar protection.^[62]^[63] Other nations have advanced APS programs tailored to regional priorities. Germany, through Rheinmetall and KNDS Deutschland, is equipping Boxer IFVs and Leopard 2A8 tanks with hybrid APS like StrikeShield in the 2020s, emphasizing modular hard- and soft-kill options for NATO interoperability, while also adopting Israel's Trophy on Leopard 2 platforms from 2024.^[64]^[65] India is developing indigenous hard-kill APS through the Defence Research and Development Organisation (DRDO), with a 2024 request for information targeting integration on Arjun and T-90 tanks to counter border threats, including prototypes demonstrated at Aero India 2025.^[66]^[67] China's GL5, developed by Norinco since the late 2010s, is a hard-kill APS for Type 99 tanks and ZBD-04 IFVs, using millimeter-wave radars and interceptors for 360-degree coverage against anti-tank weapons.^[68]^[69] South Korea's Korean Active Protection System (KAPS), developed by Hanwha Defense, entered operational service on K2 Black Panther tanks in 2025, providing hard-kill defense against ATGMs and RPGs.^[70] Ukraine has retrofitted variants like the Zaslon-L APS on T-64BV tanks, with combat testing in 2025 enhancing protection against drones and ATGMs.^[71] European collaborative efforts, such as those under the Main Ground Combat System (MGCS) program involving France and Germany, aim to standardize APS for next-generation tanks by the 2030s, focusing on integrated sensor fusion.^[1] NATO alliances prioritize APS standardization to ensure seamless operations among member states, with 2025 interoperability trials under the Coalition Warrior Interoperability eXercise (CWIX) testing networked defenses across platforms like the Abrams and Leopard 2. Export controls, enforced through regimes like the Wassenaar Arrangement, restrict APS proliferation to prevent transfer to non-allied nations, limiting access to advanced systems like Trophy and Iron Fist.^[72]^[73]

Notable Implementations

The Israeli Trophy active protection system (APS), developed by Rafael Advanced Defense Systems, has demonstrated exceptional performance in operational environments, particularly during conflicts in Gaza from 2014 onward. Deployed on Merkava Mark IV tanks and Namer armored personnel carriers, Trophy achieved a 100% success rate in intercepting anti-tank guided missiles (ATGMs) and rocket-propelled grenades (RPGs) in multiple engagements, preventing any confirmed penetrations of protected vehicles. By 2023, the system had accumulated over 50,000 operational hours, with upgrades in 2024 and 2025 enhancing its capability against top-attack threats, including kamikaze drones, through improved hemispheric coverage and radar detection. This effectiveness has been credited with saving numerous vehicles in dense urban combat scenarios, where threats like Kornet ATGMs and RPG-29s are prevalent.^[74]^[75] In contrast, the Russian Arena APS, particularly the modernized Arena-M variant, has shown mixed results in Syria since 2015 and more extensively in Ukraine from 2022 to 2025. Fielded on T-72B3M and T-90M tanks, Arena-M has intercepted anti-tank missiles such as the TOW in tests and limited combat scenarios, but struggles with salvo attacks and low-flying threats. Failures have been attributed to saturation tactics, where multiple projectiles overwhelm the system's limited interceptor capacity, leading to penetrations despite activation; for instance, several equipped tanks were disabled by FPV drones and ATGMs in Ukrainian engagements. Despite these limitations, deliveries of Arena-M-equipped vehicles increased in 2024-2025 to bolster armored survivability amid high attrition rates.^[76]^[77] The United States has integrated Trophy on M1 Abrams tanks, with significant testing conducted at Fort Hood (now Fort Cavazos) and other sites. In fiscal year 2022 evaluations by the Director, Operational Test and Evaluation (DOT&E), Trophy intercepted the majority of simulated threats, including Javelin-like ATGMs, achieving over 90% neutralization rates in controlled scenarios against recoilless rifles, ATGMs, and rockets. These trials, extended into 2023, confirmed compatibility with Abrams systems without major integration issues, though no combat deployments have occurred as of 2025; however, the technology has been exported to allies, including potential support for Ukrainian forces via U.S. aid packages. The system's performance exceeded expectations in defending against top-attack simulations, paving the way for broader Army adoption.^[78] Other notable implementations include the Elbit Systems Iron Fist APS on the Australian Redback infantry fighting vehicle (IFV). Selected under the LAND 400 Phase 3 program, Iron Fist was integrated into the 129 Redback IFVs contracted in 2023, with deliveries expected to commence in 2027, achieving full operational capability in 2027; the system provides 360-degree protection against RPGs and ATGMs using hard-kill interceptors and soft-kill jamming.^[79] In the United Kingdom, trials of the Challenger 3 main battle tank in 2024 incorporated Trophy APS testing, following a 2023 Ministry of Defence contract valued at £20 million, focusing on missile defense integration during mobility and firing assessments at sites like Lulworth. These efforts highlight growing adoption of mature APS technologies on next-generation platforms.^[80] Lessons from these implementations underscore APS's impact on armored warfare. Israeli Defense Forces (IDF) data indicates that Trophy-equipped units in high-threat urban zones experienced significantly fewer vehicle losses compared to unprotected counterparts, attributing this to proactive threat neutralization that allows sustained maneuverability. However, integration challenges persist with legacy vehicles, such as power supply demands and sensor interference, requiring extensive retrofitting. In 2025, Ukrainian forces advanced retrofits of domestic and imported APS variants on T-64 tanks, enhancing survivability against drone swarms through combined hard-kill and electronic countermeasures, though specific systems like Zaslon remain limited in scale due to supply constraints. Overall, these cases demonstrate APS reducing casualties by enabling bolder tactics while exposing needs for multi-threat adaptability.^[81]^[82]

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[PDF] Collaborative Point Paper on Active Protection Systems - DTIC
Active Protection Systems commonly consist of an array of soft- and hard-kill techniques. Soft-kill methods, similar to Electronic Counter-Measures (ECM) in ...
[12]
[PDF] Active Protective Systems: - ciar.org
9 Shtora-1 is actu- ally a soft kill, or countermeasures sys- tem. It is most effective when used in tandem with a hard kill system such as the Arena, which is ...<|control11|><|separator|>
[13]
BAE Systems to develop advanced electronic warfare ...
Nov 19, 2024 · Ground combat vehicles protect themselves from threats with laser-based countermeasure systems. ... Soft Kill System (LSKS) development ...
[14]
FM3-21.91 Chapter 1 The Role of Antiarmor Organizations
Soft-kill active protection systems cause the munitions to miss. Hard-kill active protection measures fire munitions at the incoming round to destroy, ...Missing: definition | Show results with:definition
[15]
RDECOM's road map to modernizing the Army: Next Generation ...
Dec 6, 2018 · While these active protection systems--sensors, defeat mechanisms ... Hard-kill systems use physical countermeasures such as blasts or ...Missing: definition | Show results with:definition
[16]
[PDF] Systems Engineering Approach To Ground Combat Vehicle ... - DTIC
Active protection is a relatively new and upcoming development in the field of hit avoidance. Dieter and Wagner (2009) classify active protection systems (APS) ...
[17]
Acoustic Active Protection Systems - Microflown AVISA
Wide range of acoustic vector sensor based systems for battlefield solutions. ... The sensors to activate the countermeasure usually involve (passive) optical ...
[18]
Rafael Adds Another Significant Electro Optical Sensor to Its Trophy ...
The electro optical sensor works in parallel to the radar system which is the main sensor of the Trophy. According to Rafael the electro optical sensor ...<|control11|><|separator|>
[19]
Drone Detection and Classification Based on Radar Cross Section ...
The system use Cell Averaging Constant False Alarm Rate (CA-CFAR) and achieved a range of up to 2 Km in outdoor environment containing clutter. In [80] ...
[20]
A Survey on Detection, Classification, and Tracking of UAVs using ...
Mar 7, 2025 · This survey provides UAV detection using radar, acoustic, EO sensors, RF analysis of signals emitted by UAVs, and multi-sensor fusion. The ...
[21]
An improved algorithm for target trajectory prediction in the active ...
This paper proposes an interception point prediction algorithm that combines the Kalman filter and least-squares estimation. By dynamically determining the ...
[22]
Red Shield 2/GL5 (Active protection system) - Army Guide
Target detection range: >100m. Target intercept range: 10m. Protection area: 360°, 3-dimensional. Length of whole system: <400 mm. Number of tubes: 12. Included ...Missing: engagement envelope
[23]
Iron Fist Active Protection System - Detect, Track, Neutralize
Lightweight (220 lbs per side, 551 lbs for overall platform) · All-in-One pre-calibrated unit · Bolt on, no penetration to vehicle structure · Low power draw from ...
[24]
AI Reshaping the Active Protection System Market
Jul 15, 2025 · Modern APS are capable of employing both hard kill (physical interception) and soft kill (electronic jamming or deception) tactics. The choice ...Missing: comparison | Show results with:comparison
[25]
Active And Reactive Vehicle Protection Systems - Euro-sd
May 16, 2019 · It will be mounted – together with the MAPS base kit control unit and the hard kill IRON FIST APS – on a BRADLEY IFV for a more challenging ...
[26]
Army accelerates Active Protection Systems technology - Defense One
Oct 13, 2016 · Active Protection Systems rely on computer algorithms and processors to track and destroy approaching enemy fire in a matter of milliseconds.Missing: advantages | Show results with:advantages<|control11|><|separator|>
[27]
[PDF] Effects of Directed Energy Weapons - NDU Press
Jun 16, 2017 · Mechanisms of Soft Kill . . . . . . . . . . . . . . . . . . . 244. 1 ... kW laser, so that after 50% attenuation we would have 10 kW ...
[28]
[PDF] Active Protection Systems (APS) Program - DOT&E
The APS program improves vehicle survivability against threats using a kinetic 'hard kill' mechanism to intercept and disrupt incoming threats.
[29]
[PDF] DoD Directive 3000.09, "Autonomy in Weapon Systems
Jan 25, 2023 · If unable to do so, the system will terminate engagements or obtain additional operator input before continuing the engagement. (3) The ...
[30]
Trophy APS: Operational Active Protection System - Rafael
Trophy APS is an operational active protection system that can be integrated with all armored platforms – tanks or APCs, wheeled, tracked, MBTs, and 8x8s.
[31]
How Active Protection Systems Knock Down Anti-Armor Threats for ...
Jan 17, 2020 · Soft kill APS defeats the threat without kinetics. Countermeasures include infrared jammers, laser spot imitators, and radar jammers. They may ...Missing: dazzlers mechanisms
[32]
FM 34-81-1: Battlefield Weather Effects - GlobalSecurity.org
The relationship between weather effects and EO systems is very complex since the result is a function of the precipitation particle size and the wavelength of ...<|separator|>
[33]
[PDF] WEATHER-RADAR ATTENUATION ESTIMATES FROM ... - DTIC
The attenuation of radar weather signals by intervening precipitation is difficult to estimate from the radar records themselves,, Rainfall rates observed ...
[34]
[PDF] Sand and Dust Considerations in the Design of Military Equipment
Jan 1, 2023 · 1iw damage may be caused by abrasion, clogging or blocking, or corrosion. Abrasion damage is pariicularlv important in internal combustion ...
[35]
[PDF] Active Protection Systems (APS) Program
Phase 1 testing of the Iron Fist APS implementation on Bradley has been hampered by vehicle power requirements and some component software problems. ...Missing: ammunition capacity
[36]
[PDF] Active Alignment and Vibration Control System for Large Airborne ...
The mounts utilize a combination of pneumatics and magnetics to perform the dual functions of low-frequency alignment and high-frequency isolation. Test results ...
[37]
[PDF] Climatic Extremes for Military Equipment - DTIC
Degradation due to extremes of humidity is important at the highest temperature at which these extremes exist. Thus for the moist extreme the worst ...
[38]
Review Temperature effect and thermal impact in lithium-ion batteries
The high temperature effects will also lead to the performance degradation of the batteries, including the loss of capacity and power [56], [57], [58], [59].Missing: APS | Show results with:APS
[39]
[PDF] Electronic Warfare Fundamentals
Electronic Warfare Fundamentals is a student supplementary text and reference book that provides the foundation for understanding the basic concepts.
[40]
STANAG 4370 – Environmental Testing Standards - Betalight-tactical
STANAG 4370 is a NATO standard that sets the environmental testing requirements for military equipment, ensuring durability and reliability in extreme ...Missing: active | Show results with:active
[41]
FGM-148 Javelin - Missile Threat - CSIS
Mar 17, 2022 · Top attack mode is designed to target tanks; the missile flies upward to reach a peak altitude of 150 m before striking the tank's more ...
[42]
Javelin Portable Anti-Tank Missile, US - Army Technology
Jun 2, 2023 · The missile is launched at an 18-degree elevation angle to reach a peak altitude of 150m in top attack mode and 50m in direct-fire mode.
[43]
Rafael announces Trophy APS upgrade to counter higher threats
Oct 9, 2024 · Israel's Rafael Advanced Defense Systems has upgraded its Trophy active protection system (APS) to enable it to counter unmanned aerial vehicles (UAVs) and top ...Missing: KAPS | Show results with:KAPS
[44]
Focus: Adapting Protection Systems Against Drones - Trophy APS ...
Jul 23, 2024 · FPV drones, in particular, can attack in large numbers, saturating defenses and increasing the chances of successful strikes. These drones, ...
[45]
Rising Anti-Armour Threats in Ukraine Spotlight Need for Active ...
Sep 6, 2023 · In an era of swarming drones, proliferating missiles and saturation attacks, naval air defence must combine cutting-edge effectiveness with low ...Missing: RPG | Show results with:RPG<|separator|>
[46]
Stealth Unmanned Aerial Vehicle Penetration Efficiency ... - MDPI
Jul 9, 2024 · This paper introduces a radar detection probability model to solve the weight balance problem of incident angles of the RCS and a penetration efficiency model.
[47]
[PDF] Defeating Theater Missile Defense Radars with Active Decoys
A study is made of how decoys of different levels of sophistication can defeat theater missile defense radars. In particular we describe an active decoy ...
[48]
Air Defence System Defensive Aids - Air Power Australia
The Chinese RWE-1 is a radio-frequency band active MAWS intended to protect SAM batteries from attack by anti-radiation missiles such as the AGM-88 HARM/AARGM ...
[49]
[PDF] A Networked Drone Defense Net Against Hypersonic Attack
Jul 1, 2025 · A Networked Drone Defense Net Against. Hypersonic Attack: Concept, Architecture, and Role of a Local Decision-Maker Drone.
[50]
Trophy Armored Vehicle Protection System Gains New Ability To ...
Oct 8, 2024 · The combat-proven Trophy system has gotten new improvements that provide a critical capability boost against various top-down threats.Missing: abort | Show results with:abort
[51]
Iron Fist APS | Active Protection System - Elbit Systems
Apr 16, 2018 · The series includes a light configuration for armored fighting vehicles (AFV), infantry fighting vehicles (IFV) and logistic vehicles, ...Missing: Puma 2018
[52]
Elbit to supply Iron Fist APS for upgrades to US Army's Bradley IFV
May 6, 2024 · Developed by Elbit Systems, the Iron Fist APS is a 'Hard Kill' system designed to provide 360-degree protection to armoured platforms against a ...
[53]
Russia to equip T-80BVM and T-90M tanks with Arena-M Active ...
Apr 5, 2023 · The Russian Ministry of Defense is expressing interest in equipping their Main Battle Tanks (MBTs) with the Arena-M Active Protection System (APS).
[54]
Details of ARENA-M APS Disclosed - European Security & Defence
Nov 3, 2021 · According to KBM, ARENA-M will equip Russian MBTs such as the T-90 and T-72. Earlier, Bekhan Ozdoev, Industrial Director of the Rostec ...
[55]
SHTORA-1 Active Defense System
Oct 12, 2005 · Shtora-1 protects tanks from guided missiles using IR jammers, laser warning, and thermal smoke screens. It also uses electro-optical jammers ...
[56]
[PDF] Modular Active Protection System (MAPS) Base Kit - Lockheed Martin
As the backbone of the U.S. Army's Modular Active Protection System (MAPS) framework, Lockheed Martin's MAPS base kit offers automatic, next-generation.Missing: 2015 | Show results with:2015
[57]
U.S. Army's CCDC MAPS Program Successfully Completes Layered ...
Dec 10, 2019 · The MAF and MAPS Base Kit facilitate the system's modular nature by integrating various sensor packages, hard-kill and soft-kill defeat ...Missing: definition | Show results with:definition
[58]
Artis' active protection system completes US Government testing
May 1, 2013 · Iron Curtain, an active protection system (APS) developed by Artis, has successfully demonstrated its ability to protect military vehicles against all incoming ...
[59]
[PDF] FY 2018 Annual Report - Director Operational Test and Evaluation
Aug 21, 2019 · - Rafael Trophy APS on the Army Abrams M1A2 and. Marine Corps M1A1 tanks. - Artis Iron Curtain on the Stryker. - IMI Systems Iron Fist on the ...<|separator|>
[60]
TROPHY ACTIVE PROTECTION SYSTEM ACHIEVES MAF 2.0
May 21, 2025 · The US Army certifies that the TROPHY Hard-Kill Active Protection System has successfully achieved all mandatory technical requirements for Modular APS ...
[61]
StrikeShield – Active Protection System - Rheinmetall
StrikeShield is a hybrid solution that combines active and passive protection in a modular design that can be adapted to most vehicle platforms.
[62]
KNDS Deutschland orders Trophy APS for German Army's future ...
Dec 5, 2024 · KNDS Deutschland has ordered 123 Trophy active protection systems (APSs) for the German Army's future Leopard 2A8 main battle tank (MBT) ...<|separator|>
[63]
India issues RFI to procure active protection systems for T-90 tanks
Feb 5, 2025 · The Indian Army has issued a request for information (RFI) in support of its planned procurement of a new active protection system (APS) for ...
[64]
Aero India 2025: DRDO develops hard-kill active protection system
Feb 13, 2025 · According to the officials, the APS consists of four X-band radars and two traversable effector launchers, each equipped with two anti-threat ...
[65]
GL5 Active Defense System - GlobalSecurity.org
Oct 27, 2018 · China's self-developed GL5 tank active defense system was demonstrated for the first time in 2017. This system without human intervention, ...
[66]
AirShow China 2018: GL5 hard-kill APS Active Protection System for ...
Nov 13, 2018 · The GL5 hard-kill active protection system consists of four munitions launchers, four multipurpose, millimeter-wave radars, and a control ...
[67]
5G At The Core Of NATO's Digital Transformation - Forbes
Oct 7, 2025 · CWIX 2025 tested interoperability across multinational forces. Joint Viking in Norway (the largest exercise of its kind in 2025) brought ...
[68]
What Is Interoperability — And Why It Matters to NATO
Interoperability is the ability of different systems, organizations, and nations to work together coherently, effectively, and efficiently.Missing: APS | Show results with:APS
[69]
Active Protection Systems (APS) on Military tanks Detect, Track and ...
APS typically comes in two flavors, hard kill and soft kill. A hard-kill active protection system detects, engages, and destroys or neutralizes an incoming ...
[70]
Israel's Rafael upgrades its Trophy active protection system to ...
Jan 23, 2025 · It has intercepted threats like Kornet ATGMs and RPG-29s. By 2017, Trophy accumulated 50,000 operational hours, and by 2023, production ...
[71]
Arena-M, Russia's active protection system advances
Mar 31, 2025 · Arena-M is an active protection system with 12 silos of explosive interceptors and radars. It can intercept top-attack missiles and is being ...
[72]
https://www.forbes.com/sites/nokia-industry-40/2025/10/07/5g-at-the-core-of-natos-digital-transformation/
[73]
[PDF] Active Protection System (APS) for Abrams and Bradley - DOT&E
The TROPHY APS intercepted most of the incoming threats and the Abrams tank base armor provided adequate force protection. The Army tested the Elbit Iron Fist – ...Missing: logic friendly
[74]
AS21 Redback Infantry Fighting Vehicle (IFV), South Korea
Jun 28, 2024 · The AS21 Redback is an advanced infantry fighting vehicle (IFV) proposed by South Korean company Hanwha Defense for the Australian Army.
[75]
K21 - Wikipedia
The Redback is equipped with the Elbit Iron Fist active protection system (APS) and an Elbit IronVision system that provides the crew with a 360 degree view.
[76]
UK orders Trophy APS for further testing on Challenger 3 tank - Janes
Jul 18, 2023 · The MoD reported that three weeks of assessment phase trials had been completed on the Challenger 3, with a total of 25 firings, including live ...
[77]
Active protection systems and the future of tank warfare
Apr 10, 2025 · Drozd was the first active protection system; it provided a probability of intercept between 0.7 and 1 over the frontal arc.
[78]
APS and ERA developments - Euro-sd
Jan 21, 2025 · Over the last two decades, the development of defensive solutions for armoured fighting vehicles (AFVs) has been influenced by several factors.