Method for Reducing Multipath Propagation Effects During the Processing of Replies in Mode "S"
First Claim
1. A method of processing replies from targets interrogated by a surveillance radar for interrogations in mode S, independently for each target present in the reception lobe of the radar, whereby the different targets present in the reception lobe of the radar SSR are interrogated at least once, all the reply signals received for this lobe for each target are collected after each interrogation, a reply detection processing operation is performed in a signal processing module and errors are detected and corrected and the corresponding blips are extracted,wherein said signal quality detection and determination processing operation is implemented, in the event of decoding failure by the signal processing operation, by a data processing module which forms a synthetic message with the stored set of replies to each interrogation for one and the same target, establishing, for each bit of each message, the value and the quality of this bit and performing the detection and correction of errors using this synthetic message.
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Abstract
The processing method according to the invention is a method of processing replies from targets interrogated by a surveillance radar according to a mode S interrogation of all the targets present in the receiving lobe of the radar, whereby the different targets present in the receiving lobe of the radar are interrogated at least once, the set of the mode S reply signals received for this lobe are collected after each interrogation, a reply detection processing operation is performed for each target and errors are detected and, if necessary, corrected then the corresponding blips are extracted, and this method is characterized in that said signal quality detection and determination processing operation consists in forming a synthetic message with the set of replies to each interrogation for each target, establishing, for each bit of the message, the value and the quality of this bit and performing the error detection and correction using this synthetic message, and the three variables Σ, Δ and monopulse of all the failed replies from the same target are exploited to construct the synthetic message.
This processing operation is useful in highly polluted electromagnetic environments where the existing methods are inadequate: the same target may be asked the question again for reasons other than a reply failure.
26 Citations
10 Claims
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1. A method of processing replies from targets interrogated by a surveillance radar for interrogations in mode S, independently for each target present in the reception lobe of the radar, whereby the different targets present in the reception lobe of the radar SSR are interrogated at least once, all the reply signals received for this lobe for each target are collected after each interrogation, a reply detection processing operation is performed in a signal processing module and errors are detected and corrected and the corresponding blips are extracted,
wherein said signal quality detection and determination processing operation is implemented, in the event of decoding failure by the signal processing operation, by a data processing module which forms a synthetic message with the stored set of replies to each interrogation for one and the same target, establishing, for each bit of each message, the value and the quality of this bit and performing the detection and correction of errors using this synthetic message.
Specification