Evaluating Path Loss by Extended Squitter Signals for Aeronautical Surveillance

For the successful deployment of the aeronautical surveillance systems, it is important to select the appropriate path loss model that is used in the coverage design. While the flight experiment is a traditional approach to evaluate the path loss models, the passive measurement of the 1090-MHz extended squitters (1090 ESs) broadcast by target of opportunity is a new complementary approach. This letter examines the feasibility of the 1090 ES measurement for evaluating the aeronautical path loss models. First, the effect of the alternate transmission using two transponder antennas is removed to extract the effect of the propagation channel. Then, the measurement result during the flight experiment is compared to the reference values given by free-space path loss in order to show the relevance of using the 1090 ES.