High-Intensity Radiated Fields (HIRFs) can cause severe interference to airborne GNSS equipment. This paper builds a CST model based on the real structure and evaluates shielding effectiveness (SE) with respect to frequency, material, polarization, angle of incidence, and aperture; anechoic-chamber tests combined with the DO-160G compliance method (Section 20, Class G) are then conducted, and this integrated scheme: (1) validates the simulation’s effectiveness and confirms the HIRF coupling risk; (2) reveals the GNSS failure mechanism—C/N0 decrease → DOP increase → loss of lock. Subsequently, an equation-based mechanism framework (cavity modes, slot/aperture coupling, waveguide-below-cutoff, thickness attenuation) is proposed, together with an effective-dimension correction, by which a single-point calibration can predict the remaining resonances. Accordingly, mechanism-aligned design strategies are provided (aperture control and honeycomb windows, geometric detuning and local absorbers, high-permeability inserts, multi-polarization and multi-directional protection), achieving predictable, verifiable, and quantifiable improvements in SE.
Electromagnetic compatibility (EMC) impacts of arc discharge from medium-low speed maglev trains on the VHF Data Broadcast (VDB) link of the Ground-Based Augmentation System (GBAS) are systematically investigated. Considering that a single VDB station serves multiple runways, this study evaluates how different placements of the VDB antenna relative to runway thresholds affect its susceptibility to maglev interference. Field measurements of maglev arc radiation under various operational conditions revealed a maximum radiation field strength of 57.76 dBμV/m at 113 MHz. Laboratory experiments further identified a minimum required signal-to-interference ratio (SIR) of 26 dB for reliable VDB signal decoding. Theoretical analyses demonstrate that maintaining a separation greater than 5.73 km between the maglev arc source and runway threshold is necessary to ensure signal integrity. The findings offer practical guidance for airport planning and electromagnetic protection design.
Visible–thermal tiny pedestrian detection in UAV aerial images is crucial for online decision-making in urban security and disaster response. However, the extremely small scale and sparse distribution of pedestrians cause discriminative cues to be submerged by dominant low-frequency background and contextual redundancy during feature learning. Meanwhile, cross-modal spatial misalignment and spatially varying modality reliability hinder stable fine-grained correspondence, thereby degrading fusion quality. To address these issues, QA2FDet is proposed as a quality-aware adaptive alignment fusion network comprising three modules: spectrum-spatial decoupled enhancement module (SDE), cross-modal correspondence mining module (CCM), and prior-informed gated fusion (PGF). SDE leverages the discrete cosine transform to disentangle redundant low-frequency background information, while deep semantic gating propagates high signal-to-noise ratio details into shallow representations to enhance subtle cues of tiny pedestrians and suppress high-frequency noise. To establish fine-grained neighborhood correspondences under slight spatial offsets, thermal-guided local asymmetric cross-attention is designed in CCM. Finally, region-level quality and modality discrepancy are jointly modeled for adaptive cross-modal fusion in PGF. Extensive experiments on multiple UAV-based RGBT detection benchmarks demonstrate that QA2FDet achieves state-of-the-art performance and exhibits strong robustness in challenging aerial scenes.
High-Intensity Radiated Fields (HIRF) can cause significant electromagnetic interference (EMI) to aircraft and their onboard systems, posing a threat to flight safety. To enhance the interference immunity of navigation devices, this study establishes a 3D simulation model based on the actual structure of a GNSS receiver and utilizes CST software to analyze the shielding effectiveness (SE) under varying conditions, including frequency, material properties, polarization, incident angle, and aperture configuration. The results show that structural differences, aperture coupling effects, and material characteristics have a significant impact on SE. In particular, strong single-point resonances frequently occur in the 3–10 GHz range, leading to severe SE fluctuations, while shielding performance generally deteriorates above 10 GHz due to reduced structural stability. To validate the simulation results, an anechoic chamber test was conducted, revealing signal faults in the GNSS receiver under high-frequency HIRF conditions, thereby confirming the validity of the simulation and the risk of coupling. Based on these findings, the study proposes optimization strategies including aperture control, resonance suppression, material selection, and multi-polarization/multi-directional protection, providing theoretical and engineering references for electromagnetic compatibility (EMC) design of airborne equipment in HIRF environments.
This study employs CST simulations to analyze the electromagnetic response and cable coupling characteristics of electric vertical takeoff and landing (eVTOL) aircraft under lightning conditions. Based on the SAE ARP5414B standard, lightning zoning was carried out, and three typical strike scenarios—the nose, wing, and vertical tail—were established. Referring to representative lightning current waveforms in SAE ARP5412B, Component A was selected as the primary excitation source. On this basis, the L9(33) orthogonal design method was applied to evaluate the influence of cable structure, length, and routing method on the induced current. The results show that nose attachment produces the strongest coupling to the airframe. Shielded cables effectively reduce the induced current in the conductor core by diverting most of the coupled current through the shielding layer, while unshielded single-core cables demonstrate the weakest resistance to interference. The induced current increases with cable length, and Z-shaped wall-mounted routing produces stronger coupling than straight or suspended routing. This research provides a systematic approach for evaluating indirect lightning effects in eVTOL and offers engineering guidance for electromagnetic protection and cable design.
This study employs CST simulations to analyze the electromagnetic response and cable coupling characteristics of electric vertical takeoff and landing (eVTOL) aircraft under lightning conditions. Based on the SAE ARP5414B standard, lightning zoning was carried out, and three typical strike scenarios—the nose, wing, and vertical tail—were established. Referring to representative lightning current waveforms in SAE ARP5412B, Component A was selected as the primary excitation source. On this basis, the L9(3³) orthogonal design method was applied to evaluate the influence of cable structure, length, and routing method on induced current. The results show that lightning strikes at the nose have the strongest coupling effect on the airframe, with both electric and magnetic fields exhibiting significant spatial distribution. Shielded cables effectively reduce induced current in the conductor core by diverting most of the coupled current through the shielding layer, while unshielded single-core cables demonstrate the weakest resistance to interference. Induced current increases with cable length, and Z-shaped wall-mounted routing produces stronger coupling than straight or suspended routing. This research provides a systematic approach for evaluating indirect lightning effects in eVTOL and offers engineering guidance for electromagnetic protection and cable design.