Assessing the interference of transmitting portable electronic devices to distance measurement equipment

The use of intentionally transmitting portable electronic devices, such as cell phones, WiFi devices, Bluetooth headsets, etc., is widespread and growing. RTCA Special Committee 202 has been considering guidelines for the use of such devices on aircraft. A key element of the assessment of such devices is the quantitative expression of the effect of the intentional and unintentional (spurious) emissions of such devices on the communications, navigation and surveillance radios used on the aircraft. These radios were generally not designed to accommodate interference from consumer devices operated on-board the aircraft. This paper develops the performance equations necessary to evaluate the effects of emissions from such intentionally transmitting devices to the L- Band Distance Measuring Equipment, and uses these equations to recommend appropriate susceptibility thresholds. The resultant thresholds will be incorporated into the recommendations of SC-202, as documented in a modification of RTCA/DO-294B.