Compatibility Analysis Between LDACS and GNSS L5/E5a/B2a Signals

L-band Digital Aeronautical Communications System (LDACS) is an important data link technology defined in the future communication infrastructure (FCI). However, the issue of the electromagnetic compatibility of LDACS with other existing aeronautical L-band communication, navigation, and surveillance systems has drawn widespread concern. This paper conducts both theoretical and experimental analyses on the compatibility between LDACS and Global Navigation Satellite System (GNSS) L5/E5a/B2a signals. A link budget model is constructed to estimate the LDACS signal power arriving at the GNSS receiver input. The potential scenarios for the LDACS and GNSS L5/E5a/B2a signal compatibility analysis are identified. The required antenna separation in each scenario is calculated. A lab test on the LDACS and Global Positioning System (GPS) L5 signal compatibility is conducted. Based on the analysis, it was found that the LDACS signal probably causes no interfere with the reception of GNSS L5/B2a/E5a signals in most of scenarios. When LDACS signals transmitting with a center frequency of 1000 MHz, a duty cycle of 100 %, and a power range of approximately -75 to -5 dBm, it produces no effects on the GPS L5 signal Carrier-to-Noise Density Ratio (C/N0).