METHOD FOR REDUCING MULTIPATH PROPAGATION EFFECTS DURING THE PROCESSING OF REPLIES IN MODE 'S'

摘要

The invention relates to a method for processing replies from targets interrogated by a surveillance radar, involving the Mode-S interrogation of all the targets present in the receiving lobe of the radar. The inventive method comprises the following steps: the different targets present in the receiving lobe of the radar are interrogated at least once; the set of Mode-S reply signals received for the lobe are collected after each interrogation; and a processing operation is performed for each target, comprising the detection of replies followed by the detection of errors and, if necessary, the correction of said errors and the extraction of the corresponding blips. The method is characterised in that the aforementioned processing operation involving the detection and determination of signal quality is performed by forming a synthetic message with the set of replies to each interrogation for each target, establishing the value and the quality of each bit of the message and detecting and correcting errors using said synthetic message. The three variables, Σ, Δ and monopulse, of all of the failed replies from the same target are used to form the synthetic message. Said method can be used in a very polluted electromagnetic environment where existing methods are insufficient. The same target may be asked a question again for reasons other than a reply failure.