A system comprising: a first decoder (201, 401, 501, 601) communicatively coupled to a front-end unit (211, 415, 515, 611, 619); and a second decoder (202, 402, 502, 602) communicatively coupled to the front-end unit (211,415,515,611,619), wherein the first decoder and the second decoder are configured to: detect (702, 706) automatic dependent surveillance - broadcast, ADS-B, preambles from a signal stream received via the front-end unit; decode (704, 708) ADS-B signals (301, 302, 411, 412, 413) associated with the ADS-B preambles; and output ADS-B message data (421, 422, 423, 521, 522, 523) based on the ADS-B signals, wherein the first decoder is configured to detect a first ADS-B preamble from the signal stream, and to decode a first ADS-B signal associated with the first ADS-B preamble, wherein the second decoder is configured to attempt to detect a subsequent ADS-B preamble while the first decoder is decoding the first ADS-B signal, and to decode a subsequent ADS-B signal associated with the subsequent ADS-B preamble, and characterised in that the system is further configured to enable the second decoder when the first decoder is decoding the first ADS-B signal, and to disable the second decoder when the first decoder is finished decoding the first ADS-B signal, and wherein to enable the second decoder comprises enabling preamble detection logic of the second decoder, and wherein to disable the second decoder comprises disabling the preamble detection logic of the second decoder. a first decoder (201, 401, 501, 601) communicatively coupled to a front-end unit (211, 415, 515, 611, 619); and a second decoder (202, 402, 502, 602) communicatively coupled to the front-end unit (211,415,515,611,619), wherein the first decoder and the second decoder are configured to: detect (702, 706) automatic dependent surveillance - broadcast, ADS-B, preambles from a signal stream received via the front-end unit; decode (704, 708) ADS-B signals (301, 302, 411, 412, 413) associated with the ADS-B preambles; and output ADS-B message data (421, 422, 423, 521, 522, 523) based on the ADS-B signals, wherein the first decoder is configured to detect a first ADS-B preamble from the signal stream, and to decode a first ADS-B signal associated with the first ADS-B preamble, wherein the second decoder is configured to attempt to detect a subsequent ADS-B preamble while the first decoder is decoding the first ADS-B signal, and to decode a subsequent ADS-B signal associated with the subsequent ADS-B preamble, and characterised in that the system is further configured to enable the second decoder when the first decoder is decoding the first ADS-B signal, and to disable the second decoder when the first decoder is finished decoding the first ADS-B signal, and wherein to enable the second decoder comprises enabling preamble detection logic of the second decoder, and wherein to disable the second decoder comprises disabling the preamble detection logic of the second decoder. detect (702, 706) automatic dependent surveillance - broadcast, ADS-B, preambles from a signal stream received via the front-end unit; decode (704, 708) ADS-B signals (301, 302, 411, 412, 413) associated with the ADS-B preambles; and output ADS-B message data (421, 422, 423, 521, 522, 523) based on the ADS-B signals, wherein the first decoder is configured to detect a first ADS-B preamble from the signal stream, and to decode a first ADS-B signal associated with the first ADS-B preamble, wherein the second decoder is configured to attempt to detect a subsequent ADS-B preamble while the first decoder is decoding the first ADS-B signal, and to decode a subsequent ADS-B signal associated with the subsequent ADS-B preamble, and characterised in that the system is further configured to enable the second decoder when the first decoder is decoding the first ADS-B signal, and to disable the second decoder when the first decoder is finished decoding the first ADS-B signal, and wherein to enable the second decoder comprises enabling preamble detection logic of the second decoder, and wherein to disable the second decoder comprises disabling the preamble detection logic of the second decoder.