Analysis Report on the Necessity of Electromagnetic Compatibility Testing for Low-Altitude Aircraft

Introduction

Current Status of Low-Altitude Aircraft Development and Electromagnetic Environment Challenges

In recent years, the low-altitude aircraft industry has experienced explosive growth, with its application scenarios rapidly expanding from traditional military fields to more than 20 vertical sectors including civilian logistics, agricultural plant protection, urban security, and emergency rescue. According to statistics from the Civil Aviation Administration of China, the average daily flights of low-altitude aircraft surged from 120,000 in 2023 to 850,000 in 2025, with an average annual growth rate of 38%. It is projected that the global low-altitude economy market size will exceed $2.1 trillion by 2030.

With the expansion in quantity and application scenarios, the complexity of the electromagnetic environment faced by low-altitude aircraft has increased exponentially. This environment results from the combined effects of ground-based emission sources (such as high-voltage transmission lines, 5G base stations, industrial equipment), airborne communication and navigation equipment, and natural phenomena (lightning, geomagnetic storms). It is characterized by limited spectrum resources, a wide variety of equipment types, and electromagnetic wave propagation that is easily obstructed and reflected by ground objects.

Fundamentals of Electromagnetic Compatibility (EMC)

Electromagnetic Compatibility (EMC) refers to the ability of electronic equipment, subsystems, or systems to operate normally in their electromagnetic environment without generating unacceptable electromagnetic interference to other devices in that environment. Its core theoretical framework includes three key elements: emission, transmission, and susceptibility.

The electromagnetic interference mechanisms of low-altitude aircraft have significant particularities, mainly manifested in two aspects. First, composite material airframes lead to increased lightning susceptibility. Traditional aircraft mostly use metal airframes, which can quickly dissipate and shield lightning energy through their own conductivity. In contrast, the composite material airframes widely used in low-altitude aircraft have poorer conductivity, making it difficult for lightning energy to be effectively conducted through the airframe structure, resulting in significantly increased device sensitivity to lightning interference.

Domestic Standard System

The domestic electromagnetic compatibility standard system for low-altitude aircraft can be categorized into "current standards" and "draft standards for comments." Its evolution shows a trend from device-level testing to system-level comprehensive assessment, continuously strengthening alignment with international standards.

International Standard System

The international electromagnetic compatibility testing standard system for low-altitude aircraft exhibits multi-dimensional development characteristics. Different standards have differentiated focuses based on application scenarios and technical requirements. Among them, RTCA DO-160G, issued by the Radio Technical Commission for Aeronautics (RTCA) in the United States, is the most widely used comprehensive standard, covering 16 environmental tests (including electromagnetic interference/immunity).

Comparison and Differences Between Domestic and International Standards

There are significant differences between domestic and international standards for electromagnetic compatibility testing of low-altitude aircraft in terms of technical focus, testing details, and application scenario coverage. These differences reflect both different technological development paths and divergent application requirements.

Electromagnetic Interference (EMI) Testing

Radiated Emission Testing

Radiated emission testing is a critical process for evaluating the electromagnetic radiation intensity propagated through space by low-altitude aircraft during operation. It ensures compliance with relevant standard limits and prevents interference with surrounding radio equipment and communication infrastructure. This test primarily targets the entire low-altitude aircraft and ground control stations, covering the frequency range of 30MHz to 18GHz, which includes core communication and navigation bands (such as 2.4GHz and 5.8GHz).

Conducted Emission Testing

Due to the dense battery layout and high-frequency switching characteristics of motors, the internal power system of low-altitude aircraft can easily become the main coupling path for conducted interference. Electromagnetic noise generated by the Battery Management System and motor controllers during high-frequency switching may be conducted through power lines to ground stations or other equipment, leading to risks such as power supply abnormalities and data transmission interruptions.

Electromagnetic Susceptibility (EMS) Testing

Radio Frequency Electromagnetic Field Radiated Immunity

In densely populated urban electromagnetic environments, where base station density is generally ≤500 meters per station, low-altitude aircraft like drones need to maintain stable operation amidst complex radio frequency fields. In such environments, wide-band interference from radio communications, navigation signals, radar signals, etc., intertwines, posing severe challenges to the aircraft's anti-interference capabilities.

Electrostatic Discharge (ESD) and Surge Immunity

Low-altitude aircraft face significant electrostatic discharge (ESD) risks in multi-person operational scenarios. For instance, frequent contact with equipment by operators during agricultural plant protection operations, or interactions between personnel and aircraft components during logistics loading and unloading, can trigger discharges due to accumulated human body static electricity.

Special Scenario Testing

With the rapid development of low-altitude aircraft cluster operations, such as the popularization of application scenarios like drone fleet performances and coordinated logistics distribution, the mutual interference of radio frequency signals between multiple aircraft and their superposition effects have become key factors affecting system safety and reliability.

Main Conclusions

The necessity of Electromagnetic Compatibility (EMC) testing for low-altitude aircraft can be systematically summarized into the "Four Quadrants of Necessity": Safety Assurance, Regulatory Compliance, Performance Optimization, and Cost Control. Together, these four aspects form the foundational support for the large-scale development of the low-altitude economy.

Policy and Technical Recommendations

To promote the improvement of the Electromagnetic Compatibility (EMC) testing system for low-altitude aircraft and the healthy development of the industry, coordinated efforts are needed from three aspects: policy, technology, and international collaboration.