UAV EMC Testing Explained: The Expensive Certification Step You Need to Understand
UAV is reshaping the operation mode in logistics, rescue, surveying, patrol and other fields. However, behind this technological innovation, it is facing the "invisible threat" of electromagnetic interference. Electromagnetic interference may not only cause the UAV to crash out of control, but may also cause it to become an "airborne interference source", posing a chain threat to peripheral equipment. Electromagnetic compatibility (EMC) testing is a key part of protecting flight safety in this invisible game.
EMC testing overview
Core terminology explained
EMC (Electromagnetic Compatibility)： Electromagnetic compatibility includes two parts: EMI and EMS.
EMI (Electromagnetic Interference)： Electromagnetic interference, the impact of noise emitted by equipment on other equipment.
EMS (Electromagnetic Susceptibility)： Electromagnetic immunity, the ability of a device to maintain normal operation when subjected to interference.FAR (full anechoic chamber)\& SAC (semi-anechoic chamber): Two different types of shielded test environments.
Why care about EMC
Ensure flight reliability: In complex electromagnetic environments, external interference can cause navigation and communication modules to fail; EMC testing can detect and repair hidden dangers in advance.Avoid "secondary pollution": If the UAV's own electromagnetic radiation exceeds the standard, it will not only violate regulations, but also interfere with ground equipment and other aircraft.Compliance and market access: National standards GB 42590-2023, GB/T 38909-2020, etc. put forward rigid requirements for UAVEMC performance, and the qualification report is a pass for legal operation.
EMC test items
The national standard GB 42590-2023 "Safety Requirements for Civilian Unmanned Aircraft Systems" clearly requires special electromagnetic compatibility (EMC) testing for light/small UAVs, and systematic experiments to verify their anti-interference and radiation suppression capabilities in complex electromagnetic environments. The test items are as follows:
Test case analysis
by SU17 UAV For example, in conjunction with the GB/T 38909-2020 standard, we continuously adjusted the antenna layout and installed shielding covers in the RE test, and finally reduced the frequency points with excessive envelopes to within the specifications; in the RS test, we achieved effective suppression of high-frequency interference by optimizing PCB routing and grounding design.
radiated emissions
The core purpose of the Radiated Emission (RE) test is to evaluate whether the electromagnetic energy unintentionally emitted by electronic equipment into the surrounding space during operation complies with regulatory requirements to avoid causing interference to other equipment or systems. SU17 selects the most stringent outdoor and industrial environments among the radiated emission limits. The measurement distance adopts the 3m method.
Figure 1-Schematic diagram of RE test site
Figure 2-SU17 before rectification
Figure 3-SU17 after rectification
As can be seen from the comparison chart, continuous rectifications have been made to resolve the issues from envelope over-standard to frequency-point over-standard, so that SU17 finally meets the index requirements (with a margin of about 3dB).
Power frequency magnetic field
The purpose of the power frequency magnetic field test is to evaluate the anti-interference ability of electronic equipment in a 50Hz/60Hz power frequency magnetic field environment to ensure that it can work normally without interference in power systems, industrial equipment or strong magnetic field environments. SU17 is tested at 30A/m according to field strength in outdoor and industrial environments.
Figure 4-Schematic diagram of RE__ power frequency magnetic field test site
radio frequency electromagnetic field radiation
The purpose of the radio frequency electromagnetic field radiation immunity test (RS) is to evaluate the anti-interference ability of electronic equipment in a high-frequency electromagnetic field environment to ensure that it can still work normally when interfered by external radio frequency signals (such as wireless communications, radar, broadcast, etc.). SU17 is tested according to the outdoor and industrial environment field strength of low-frequency band 80M~1G at 10A/m and high-frequency band 1.4G~6G at 3A/m.
Figure 5-RS__ test site diagram
electrostatic discharge
The core purpose of electrostatic discharge (ESD) testing is to evaluate the anti-interference ability and reliability of electronic equipment when subjected to electrostatic shock, and to ensure that it will not cause functional failure or hardware damage due to electrostatic discharge in real use scenarios.
Figure 6-ESD__ test site diagram
EMC testing is not only a "hard threshold" for regulatory access, but also a "safety valve" for product iteration. With the popularization of new wireless technologies such as 5G and Starlink, the electromagnetic environment will become more complex. Only by continuing to deepen EMC design and verification can domestic UAVs fly more steadily and further in the wave of low-altitude economy.
