Back to News & Events Unmanned systems, whether flying in the skies as UAVs or navigating the seas as autonomous surface and underwater vehicles, depend on one foundation above all else: reliable and standards-compliant power. These platforms integrate propulsion systems, mission payloads, autonomy computers, and high-power communications into a single electrical ecosystem. If the power supply is unstable or incompatible with military requirements, mission performance quickly suffers. This is why engineers are increasingly focused on designing and selecting military power supply solutions that meet stringent standards.
In this article, we explore the technical frameworks that govern power supply requirements for UAVs and autonomous marine craft. We will cover the most relevant standards including MIL-STD-704, MIL-STD-461, MIL-STD-810, RTCA DO-160, MIL-STD-1399-300, NATO STANAG 1008, IEC 60945, and battery safety rules from ABS, DNV, and IEC 62619, and explain how they shape design choices. We will also discuss cross-domain priorities and share examples of products that illustrate how these standards come to life in real systems.
Why Standards Matter in Autonomous Systems
Military environments are unforgiving. UAVs contend with generator fluctuations, motor drive ripple, lightning strikes, and high-altitude extremes. At sea, unmanned surface and underwater vehicles face voltage modulation from pulsed loads, harsh salt-fog conditions, and battery safety concerns in confined hulls.
Without a disciplined approach rooted in standards, power supplies can become weak points: avionics reset during a voltage sag, communications drop out under EMI, or a Li-ion pack overheats in saltwater conditions. Standards such as MIL-STD-704 for airborne platforms and MIL-STD-1399-300 for naval systems codify worst-case conditions. By designing to these requirements, engineers ensure interoperability and mission readiness. EMC documents like MIL-STD-461 and IEC 60945 then guarantee that the supply itself is not a source of interference, while environmental guidelines like MIL-STD-810 and DNV Rules verify survivability. Together, they form the backbone of any robust military power supply solution.
UAV and Drone Power Supply Requirements
Input Power Interfaces: MIL-STD-704
Medium and large UAVs typically operate from buses similar to those found in manned aircraft. The governing standard here is MIL-STD-704, which defines the characteristics of aircraft electrical power provided at the utilization point. Originally developed for manned military aircraft, this standard specifies acceptable voltage ranges, frequency tolerances, ripple limits, surge immunity, and transient response characteristics that equipment must withstand when connected to aircraft power buses. It covers both 28 VDC and 115/200 VAC 400 Hz systems, detailing normal, abnormal, and emergency operating conditions.
For UAV applications, MIL-STD-704 is essential because it ensures power supplies can survive the electrical disturbances common in aircraft environments. For instance, a UAV running from a 28 VDC bus must tolerate voltages as low as 18 V in abnormal modes or spikes above 50 V during generator reconnection or load dump events.
To comply, engineers design wide-range DC-DC front ends with transient suppressors, hold-up energy storage, and filters capable of absorbing bus disturbances. In AC-fed UAVs, power factor correction stages and harmonic filters ensure efficiency while remaining within the 400 Hz requirements outlined in MIL-STD-704.
Electromagnetic Compatibility: MIL-STD-461
EMI control is critical because UAV payloads often include GPS, encrypted radios, or radar systems. MIL-STD-461 is the Department of Defense standard for controlling electromagnetic interference in military systems. It establishes test methods, limits, and procedures for both conducted and radiated emissions (the electrical noise a device produces) and susceptibility (a device’s ability to operate correctly in the presence of electromagnetic interference). The standard includes specific test procedures like CE102 for conducted emissions on power leads and RE102 for radiated emissions.
For UAV power supplies, MIL-STD-461 compliance is critical because these supplies operate in close proximity to sensitive navigation and communication systems. Power supplies must remain quiet on the DC bus while also resisting interference from external RF sources that could disrupt voltage regulation or introduce noise into downstream electronics.
Designers achieve compliance by incorporating common-mode chokes, LC input filters, shielded enclosures, and careful PCB layouts. Early pre-compliance testing reduces the risk of late-stage failures during qualification.
Environmental Survivability: MIL-STD-810 and DO-160
Unmanned aerial systems encounter temperature extremes, vibration near rotors, and pressure variations at altitude. MIL-STD-810 is a comprehensive environmental engineering standard that defines test methods for equipment exposed to harsh environmental conditions. It covers over 20 different environmental stressors including temperature extremes (-55°C to +95°C operational), thermal shock, humidity, altitude (reduced pressure), vibration, mechanical shock, rain, dust, sand, and solar radiation. Each method includes detailed test procedures and acceptance criteria.
For UAV power supplies, MIL-STD-810 ensures the hardware will function reliably whether deployed in arctic conditions, desert heat, or at high altitude where air density and cooling capacity are reduced. The vibration and shock tests are particularly important for rotary-wing UAVs where motors and propellers create continuous mechanical stress.
Complementary to this, RTCA DO-160 is an environmental standard specifically developed for airborne equipment by the Radio Technical Commission for Aeronautics. While similar in scope to MIL-STD-810, DO-160 adds aviation-specific categories including lightning indirect effects, RF susceptibility, magnetic effect, power input quality, and voltage spike testing. It also defines environmental categories (like temperature ranges from A to F) that allow designers to tailor testing to the actual operating envelope.
DO-160 is particularly relevant for UAV power supplies that must integrate with certified avionics or operate in controlled airspace, as it addresses concerns unique to aviation such as electromagnetic effects from lightning strikes and altitude-related pressure changes.
Meeting both standards requires rugged packaging. Conduction-cooled DC-DC modules, conformal coatings, and positive-locking connectors are common solutions. These measures ensure UAV supplies continue operating in environments where commercial devices would fail.
UAV Power Architecture
A UAV power system usually begins with a primary source such as a Li-ion pack, fuel cell, or generator. This feeds a conditioning stage designed to ride through MIL-STD-704 disturbances. From there, multiple isolated rails power avionics, servos, and RF payloads. Designers separate noisy loads (propulsion drives) from sensitive ones (navigation electronics) and incorporate redundancy where mission safety demands it.
Across this architecture, the military power supply solution must demonstrate compliance with MIL-STD-704 input conditions, MIL-STD-461 EMI limits, and MIL-STD-810/DO-160 environmental tests.
Autonomous Marine Vehicles: USV and UUV Power Requirements
Shipboard Interfaces: MIL-STD-1399-300 and STANAG 1008
Autonomous surface and underwater vehicles often connect to naval or mothership grids during charging or data transfer. MIL-STD-1399-300 is the U.S. Navy standard that defines the electrical power characteristics, quality, and distribution for shipboard systems. Section 300 specifically covers interface and performance requirements for electric power systems operating at 60 Hz, including voltage regulation limits, frequency stability, harmonic distortion allowances, voltage unbalance limits, and transient response requirements. It ensures that equipment connected to naval power grids can operate reliably despite the unique electrical disturbances caused by large pulsed loads like radar systems, weapons, and propulsion drives.
For autonomous marine vehicles, MIL-STD-1399-300 compliance is essential when interfacing with mothership or shore-based charging systems. The standard ensures power supplies can handle the voltage sags, frequency deviations, and harmonic distortion typical of naval electrical systems without compromising charging efficiency or damaging onboard electronics.
NATO STANAG 1008 (Standardization Agreement) complements this by defining the characteristics of electrical power supplied in NATO warships. It sets strict limits on voltage modulation (±6% for steady-state, ±16% for transient), frequency variation (±3%), and provides guidelines for power factor and harmonic content. STANAG 1008 ensures electrical interoperability across allied naval vessels, critical for autonomous systems that may operate with multiple nations’ fleets.
For USV and UUV power systems, STANAG 1008 compliance guarantees that charging and data transfer interfaces will function correctly whether connected to a U.S., British, or other NATO vessel, eliminating compatibility issues during multinational operations.
Supplies that do not meet these criteria risk destabilizing the vehicle or the larger naval power network. To comply, engineers design input stages with surge absorbers, harmonic filters, and buffer energy storage that ride through shipboard disturbances.
EMC and Environmental: IEC 60945
Marine environments bring their own challenges, particularly for navigation and communication equipment. IEC 60945 is an international standard published by the International Electrotechnical Commission that specifies general requirements, test methods, and required test results for maritime navigation and radiocommunication equipment and systems. It covers EMC requirements (both emission and immunity), environmental testing (temperature, humidity, vibration, inclination), and protection against water ingress and corrosion. The standard ensures equipment can withstand salt-laden atmospheres, continuous vibration from wave action, and the electromagnetic environment of a vessel with multiple radio systems.
For autonomous marine vehicle power supplies, IEC 60945 is particularly relevant because it addresses the unique combination of harsh maritime conditions and sensitive electronics. Compliance ensures that power supplies neither interfere with onboard radios and GPS systems nor succumb to humidity, salt fog, or vibration that would cause premature failure.
Design solutions include IP67-sealed enclosures, corrosion-resistant coatings, and conductive gasketing to control EMI. These measures are non-negotiable in marine deployments.
Energy Storage Safety: ABS, DNV, IEC 62619
Autonomous vessels rely heavily on onboard batteries. Lithium-ion chemistries dominate, but their integration is heavily regulated. The American Bureau of Shipping (ABS) is a maritime classification society that issues requirements for safe installation and operation of lithium-ion battery systems aboard vessels. ABS Guide for Use of Lithium Batteries in the Marine and Offshore Industries covers installation location, ventilation requirements, fire detection and suppression systems, thermal management, and battery management system (BMS) requirements. The related ABS Guide for Hybrid Electric Power Systems extends these requirements to vessels using hybrid propulsion architectures combining batteries with generators or fuel cells.
For autonomous marine vehicles, ABS requirements ensure that high-energy battery installations are compartmentalized, monitored, and protected against thermal runaway events that could endanger the vessel. These rules are particularly stringent because marine environments limit escape options and fire-fighting access.
Meanwhile, DNV Rules (Det Norske Veritas, another major classification society) Part 6 Chapter 2 covers electrical installations and specifies detailed requirements including creepage and clearance distances for insulation, fault protection schemes, circuit isolation, ingress protection ratings (IP codes), and cable routing requirements. DNV rules are comprehensive and cover the entire electrical system from generation through distribution to loads.
For marine vehicle power systems, DNV compliance ensures electrical safety through proper isolation, overcurrent protection, and physical robustness that prevents short circuits or ground faults even in wet, corrosive conditions.
At the cell level, IEC 62619 is an international safety standard specifically for secondary lithium-ion cells and batteries used in industrial applications. It defines test procedures for electrical safety (overcharge, over-discharge, short circuit), mechanical safety (vibration, shock, crush), thermal safety (thermal abuse, temperature cycling), and environmental protection. Cells and battery packs meeting IEC 62619 have demonstrated they can withstand abuse conditions without fire, explosion, or electrolyte leakage.
For autonomous vessel designers, IEC 62619 compliance at the cell level provides the foundation for a safe battery system, ensuring individual cells have passed rigorous safety testing before integration into larger packs.
For engineers, this means compartmentalized designs with thermal propagation barriers, gas venting channels, BMS redundancy, and fire suppression systems. These rules ensure that a failure in one cell does not compromise the entire vessel.
Cross-Domain Design Priorities
While UAVs and USVs differ in environment, they share several design imperatives. Both require power supplies capable of riding through bus disturbances, controlling EMI, surviving environmental extremes, and safely managing energy storage.
Transient immunity is critical. UAVs must withstand MIL-STD-704 dropouts, while USVs must remain stable under STANAG 1008 modulation. EMI control must be baked in from the start, using star-grounding and shielded cabling to meet MIL-STD-461 or IEC 60945. Environmental hardening addresses vibration, shock, salt fog, and temperature swings, while energy storage safety ensures compliance with IEC 62619 and ABS/DNV rules.
Efficiency and density remain constant drivers. High-power UAV payloads demand GaN or SiC switching for fast transient response, while marine propulsion inverters call for rugged conduction-cooled modules with efficiencies exceeding 92–95%. Across domains, these qualities define what engineers look for in a military power supply solution.
Verification and Test Strategies
Verification is not optional. It is central to qualifying power supplies for mission-critical platforms. For UAVs, testing begins with MIL-STD-704 input compliance, followed by MIL-STD-461 EMI scans and MIL-STD-810 or DO-160 environmental trials. For USVs and UUVs, the focus shifts to MIL-STD-1399-300 bus compliance, STANAG 1008 modulation checks, and IEC 60945 EMC and environmental assessments. Batteries are reviewed against ABS and DNV rules, with cell-level tests per IEC 62619.
Programs that integrate these standards early avoid costly redesigns and reduce the risk of mission failure.
Emerging Considerations for Modern Unmanned Systems
Small UAV and Group 1/2 Drone Power Challenges
While much of this article focuses on medium-to-large platforms, small tactical drones (Group 1: <20 lbs, Group 2: 21-55 lbs) present unique power challenges. These systems often operate from commercial-off-the-shelf (COTS) battery packs and may use simplified power architectures. However, military applications still demand ruggedization.
Key considerations include rapid hot-swap battery exchange for continuous operations, lightweight power distribution that doesn’t compromise flight time, resistance to EMP and directed energy threats in contested environments, and integration with soldier-portable charging systems that may run from vehicle batteries or tactical generators.
Engineers working on small UAV power systems should consider MIL-STD-461 conducted immunity tests even if full qualification isn’t required, conformal coating and potting for moisture resistance, and low-quiescent-current designs to maximize loiter time.
Power Distribution Architecture and Fault Management
Modern unmanned systems increasingly use intelligent power distribution units (PDUs) rather than simple wiring harnesses. These PDUs provide solid-state circuit protection with faster response than mechanical breakers, load prioritization and shedding during brownout conditions, real-time power monitoring and telemetry for predictive maintenance, and hot-swap capability for redundant supplies.
For mission-critical applications, architects should implement N+1 redundancy on essential buses, cross-strapping between independent power sources, graceful degradation modes that maintain core functions during partial failures, and autonomous fault isolation to prevent cascading failures.
Standards like MIL-STD-1275 (for ground vehicle 28V power) and SAE AS50881 (wiring practices) become relevant here, even though they’re not platform-specific.
Thermal Management in Confined Spaces
UAVs face unique thermal challenges: conduction cooling is often the only option in sealed enclosures, solar heating can raise internal temperatures 20-30°C above ambient, and altitude reduces convective cooling effectiveness by 50% or more at 15,000 feet.
Marine vehicles have different but equally challenging thermal constraints, with sealed enclosures preventing natural convection, seawater cooling available but requiring corrosion-resistant interfaces, and battery compartments requiring active cooling to prevent thermal runaway.
Power supply selection should prioritize high-efficiency topologies (>90%) to minimize heat generation, thermal interface materials rated for military temperature ranges, and derating analysis at maximum altitude or depth operating conditions.
Cybersecurity and Power Management Communications
As unmanned systems become more autonomous and networked, power management systems increasingly incorporate digital communications (CAN bus, Ethernet, MIL-STD-1553). This creates cybersecurity vulnerabilities. MIL-STD-1553 is a military data bus standard providing deterministic, fault-tolerant communication for avionics and mission systems.
Secure power architecture should include authenticated communications between BMS and flight controller, isolation between power management and mission networks, firmware update verification and rollback capability, and intrusion detection for anomalous power consumption patterns that might indicate cyber compromise.
Energy Harvesting and Hybrid Architectures
Long-endurance missions are driving interest in hybrid power architectures that combine multiple energy sources. Solar panels on high-altitude long-endurance (HALE) UAVs, fuel cells providing primary power with batteries for peak loads, regenerative braking on ground vehicles charging onboard batteries, and wave energy harvesting on surface vessels.
These architectures require sophisticated power management controllers (PMCs) that can balance multiple sources, implement maximum power point tracking (MPPT) for solar arrays, manage state-of-charge across heterogeneous storage (batteries, ultracapacitors), and maintain bus stability during source transitions.
Standards like MIL-HDBK-1275 provide guidance on integrating alternative energy sources into military platforms
Real-World Design Trade-offs
Weight vs. Redundancy
Every gram matters in UAV design. A redundant power supply might add 200-500g, equivalent to 10-20% of small UAV payload capacity. Engineers must balance mission-critical reliability against flight performance. Solutions include partial redundancy (redundant controllers, shared power stages), progressive degradation architectures where loss of one supply reduces capability but maintains core functions, and mission-specific configuration where high-risk missions carry redundant supplies while training flights do not.
COTS Adaptation vs. Mil-Spec Native
Fully qualified military power supplies can cost 10-50x more than industrial COTS equivalents. For rapid prototyping, developmental systems, or lower-tier applications, adapted COTS components may be appropriate. However, teams should carefully assess limits of the COTS approach, including which environmental tests can be waived, whether conducted immunity testing is sufficient without full MIL-STD-461 qualification, how to implement adequate quality screening, and what documentation is required to support airworthiness or seaworthiness certification.
The risk-based approach might use COTS for non-critical subsystems, industrial-grade for developmental platforms, and full mil-spec for production systems or critical functions.
Size, Weight, Power, and Cost (SWaP-C) Optimization
Modern unmanned systems demand extreme SWaP-C optimization. Strategies include using wide-bandgap semiconductors (GaN, SiC) for higher switching frequencies and smaller magnetics, 3D packaging and additive manufacturing for dense integration, multi-function integration where EMI filters, transient protection, and conversion are combined in single modules, and standardized form factors (VITA, VPX) for modularity.
Power density targets for next-generation military supplies typically exceed 100 W/in³ for DC-DC converters and 20 W/in³ for AC-DC supplies.
Engineer’s Quick Checklist
- Identify bus type and applicable standard (MIL-STD-704, MIL-STD-1399-300, or STANAG 1008)
- Define pulsed load profiles and size local energy buffering
- Plan EMI control to meet MIL-STD-461 or IEC 60945 from the start
- Select efficient conversion topologies (GaN, SiC) for high-dynamic loads
- Build redundancy and ride-through capacity into mission-critical rails
- Validate environmental compliance using MIL-STD-810, DO-160, or IEC 60945
- Ensure batteries comply with IEC 62619 and are installed to ABS/DNV requirements
- Consider cybersecurity implications of networked power management
- Evaluate SWaP-C trade-offs against mission criticality
- Plan thermal management strategy appropriate to the platform environment
- Assess COTS vs. mil-spec trade-offs for development phase and production
Recommended Product Examples
To illustrate how theory translates into practice, here are a few examples that represent the kind of modules engineers might evaluate when specifying a military power supply solution. These examples can be linked directly to Horizon’s portfolio pages:
VPT SVLHF Series DC-DC Converters
Conduction-cooled modules optimized for 28 VDC avionics buses, compliant with MIL-STD-704 input ranges and MIL-STD-461 EMI limits. Ideal for UAV avionics or payload power.
VSCF EMI Filters
Compact filters engineered to meet MIL-STD-461 CE102 conducted emission requirements. Commonly paired with DC-DC converters in UAVs and USVs to ensure EMI compliance.
Delta MDS-400 Series AC-DC
Ruggedized open-frame AC-DC supplies with medical and industrial approvals, suitable as a baseline for naval or marine system adaptation. When hardened to MIL-STD-1399-300, they provide a stable interface to shipboard grids.
These examples demonstrate the breadth of approaches, from DC-DC converters and EMI filters to rugged AC-DC supplies. For more details, you can explore Horizon’s dedicated Military/Defense Application Page, which consolidates product offerings tailored to defense and aerospace missions.
Conclusion
Whether in the skies or at sea, uncrewed defense platforms live or die by the quality of their power systems. By aligning with MIL-STD-704, MIL-STD-461, MIL-STD-810, RTCA DO-160, MIL-STD-1399-300, STANAG 1008, IEC 60945, and the safety frameworks from ABS, DNV, and IEC 62619, engineers can deliver systems that are electrically compatible, EMI-resilient, environmentally hardened, and safe to operate.
For teams evaluating or designing a military power supply solution, the lesson is clear: power is not just another subsystem. It is the backbone of autonomy. Supplies built to these requirements enable UAVs, drones, and autonomous marine vehicles to perform reliably under the most demanding military conditions, ensuring mission success where failure is not an option.
