Robustness of Ethernet in complex aircraft environment

As in all industries, electrical systems on board of modern aircraft become increasingly complex up to the point, where conventional cabling becomes inapt because of weight or size. Additionally modern materials in aircraft practically forbid classical ground referenced signals on dedicated wires. Digital data transmission by busses or networks allows a high data rate and a great reduction of wiring. At the same time, the robustness against electromagnetic interference (EMI) is strongly increased. For this paper, the robustness of Ethernet signals in an aircraft environment has been evaluated. The analysis was performed for conducted EMI, technically speaking for low frequency crosstalk and high intensity radio frequencies (HIRF). The result shows a very high robustness of the analysed Ethernet standards. By using disturbance signals according to common test standards it was not possible to directly disturb the Ethernet data transmission in the aircraft environment. The threshold to interfere with the data integrity of an Ethernet transmission is much higher than the threshold of direct effects to the analysed Ethernet hardware. With regard to the analysed types of EMI, the equipment qualification is sufficient to prove undisturbed data transfer over Ethernet connections as any hardware on aircraft is subject to strict equipment qualification.