Secondary Surveillance Radar Mode S Track Combiner
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Solution Overview
Problem
Conventional secondary surveillance radar systems face challenges in accurately eliminating unnecessary Mode A/C target reports, leading to incorrect collision alerts and incorrect rejection of valid reports due to low validity values and positional correlations.
Innovation Solution
The system transmits specific interrogations to aircraft transponders, generates and analyzes Mode S and Mode A/C target reports, and uses a combiner to eliminate unnecessary Mode A/C reports by comparing track information from both modes, ensuring accurate identification and rejection of reports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a combiner is provided to eliminate unnecessary Mode A/C target reports by comparing positional information, then the capability to reduce unnecessary reports is improved, but incorrect rejection of valid reports occurs when validity values are low
Solution Approach 1:
The system performs preliminary actions by transmitting multiple types of interrogations (Mode S only all call, Mode A only all call, Mode C, Mode A, Mode C only all call) before generating target reports. This allows the system to collect comprehensive data from transponders in advance, enabling more accurate subsequent judgment on report validity and reducing incorrect rejection of valid reports while maintaining the capability to eliminate unnecessary reports.
2Adaptability or versatility
If Mode S and Mode A/C are used in combination in the same SSR, then the versatility of information acquisition is improved, but unnecessary Mode A/C replies are received even when Mode S transponder functions properly
Solution Approach 1:
The system segments the interrogation process into distinct types (Mode S only all call interrogation, Mode A only all call interrogation, Mode C interrogation, Mode A interrogation, Mode C only all call interrogation). Each segmentation targets specific information needs, allowing the system to acquire various kinds of aircraft information while reducing the quantity of unnecessary replies by precisely controlling which interrogations are transmitted based on current operational requirements.
3Reliability
If any Mode A/C target report with low validities is rejected based on positional correlation, then the capability to eliminate unnecessary reports is improved, but valid reports may be incorrectly rejected due to distance information indicating slant range
Solution Approach 1:
The system uses feedback mechanisms by comparing positional information, validity values (Va and Vc), and distance information from multiple interrogation types. The feedback loop allows the system to continuously refine its judgment on report validity, distinguishing between unnecessary reports that should be rejected and valid reports that should be retained, thereby improving both the capability to reject unnecessary reports and the accuracy of aircraft identification.
Data Source
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AI summary
Provided is a secondary surveillance radar with an improved capability of eliminating an unnecessary Mode A/C target report, which includes a transmission unit transmitting interrogations, a reception unit receiving replies, from a transponder, corresponding respectively to the interrogations, and a signal processing unit generating a Mode S target report and a Mode A/C target report from the replies. The radar also includes a combiner generating a Mode S track and a Mode A/C track respectively from the Mode S and the Mode A/C reports, and then judging whether the Mode S report and the Mode A/C report are of the same target on the basis of the Mode S and the Mode A/C tracks. When the Mode S and the Mode A/C reports are of the same target, the combiner rejects the Mode A/C report.