GLRT Preamble Detection for Satellite ADS-B

Satellite-based automatic dependent surveillance broadcast (ADS-B) is considered as suitable technology for the next generation air traffic management, which offers the opportunity of real-time aircraft surveillance even in remote areas where ground stations cannot be installed. For a correct reception of the A D S - B message, the receiver must preliminarily detect the packet preamble. This task m a y be particularly critical in space-borne applications, where the transmitted signal experiences high path attenuation before reachingthe receiver. Existing methods for preamble detection are mostly based on heuristic reasoning and work poorly in a low signal-to-noise ratio (SNR) scenario. This motivates the search for an improved scheme obeying to some optimality criterion that can operate successfully in a satellite-based A D S - B system. In this work, w e use the generalized likelihood ratio test (GLRT) criterion to develop a novel algorithm for reliable detection of the A D S - B message. Its peculiar feature is that, in addition to the packet preamble, also a part of the subsequent data block can be embedded in the detection process. Computer simulations indicate that the proposed scheme outperforms existing alternatives and is tolerant to residual frequency errors.