Mode S Radar Code Verification and Interrogation Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional Mode S radars face issues with incorrect detection of Mode A code data, leading to adverse effects on air traffic control due to a high error rate, and doubling the number of interrogations and replies, which increases RF channel occupation time and affects data link communications.
Innovation Solution
The Mode S radar system repeatedly transmits Mode S all-call interrogations for initial acquisition, then uses selective interrogations to obtain and verify Mode A codes, storing identical codes for subsequent scans, reducing the need for repeated Mode A code requests and enhancing data accuracy by confirming code identity across multiple scans.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If Mode A code is obtained only in the initial scan after initial acquisition, then the number of interrogations and replies is reduced, but the detection precision of Mode A code decreases due to potential incorrect detection
Solution Approach 1:
The patent applies preliminary action by obtaining the Mode A code in advance during the initial scan after initial acquisition, storing it for subsequent scan processing. This allows the system to prepare the code data beforehand, reducing the need for repeated interrogations while ensuring the code is captured at a critical early stage when the target is first identified and tracked.
Solution Approach 2:
The patent uses copying by storing the Mode A code obtained in the initial scan and reusing this copied data for generating detection reports in subsequent scans. Instead of repeatedly interrogating the target for the Mode A code, the system copies the previously obtained code and applies it across multiple scans, reducing communication overhead while maintaining operational efficiency.
2Measurement precision
If Mode A code is obtained in every scan, then the detection precision of Mode A code is improved, but the RF channel occupation time increases affecting data link communications
Solution Approach 1:
The system performs the Mode A code acquisition in advance during the initial scan, capturing the code data before subsequent scans. This preliminary acquisition eliminates the need for repeated code requests in every scan, thereby reducing RF channel occupation time and freeing up bandwidth for data link communications while maintaining code accuracy.
Solution Approach 2:
The patent copies the Mode A code obtained during the initial scan and reuses this copied information for generating detection reports in subsequent scans. This approach eliminates redundant interrogations and replies for Mode A code in every scan, significantly reducing RF channel occupation time and allowing more channel capacity to be allocated to data link communications.
3Loss of time
If Mode A code is obtained only in the initial scan, then the RF channel usage is optimized, but the reliability of detection reports decreases due to potential code errors
Solution Approach 1:
The patent implements feedback by using the Mode A code obtained in the initial scan and applying it consistently across subsequent scan processing. The system feeds back this code information to the detection report generation process, ensuring that the same code is used throughout the tracking sequence, which maintains reliability while optimizing channel usage.
Solution Approach 2:
The system copies the Mode A code from the initial scan and uses this copied data for generating all subsequent detection reports. This copying approach ensures consistency and reliability of the code across multiple scans while minimizing RF channel occupation, as the code is not re-interrogated but rather reused from the initial acquisition.
4Measurement precision
If the number of scans is increased to verify Mode A code identity, then the detection precision is improved, but the processing time and channel occupation increase
Solution Approach 1:
The patent performs Mode A code verification in advance during the initial scan phase, before entering the routine surveillance scans. By completing the code acquisition and verification process preliminarily, the system avoids the need for extended verification procedures in subsequent scans, thereby maintaining high detection precision while minimizing additional processing time and channel occupation.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Disclosed is a Mode S radar which specifies an aircraft by transmitting interrogations to an aircraft A equipped with a Mode S transponder, and by then receiving and decoding replies corresponding to these interrogations. In the Mode S radar, detection reports on the aircraft A are generated in a manner that: for a Mode A code necessary for generating detection reports, when identicalness between the Mode A codes obtained in a plurality of scans after the initial acquisition of the aircraft A has been found to exist, the Mode A code thus found identical is adopted without carrying out a Mode A code interrogation (UF=5) thereafter. Accordingly, the Mode S secondary surveillance capable of generating more highly reliable detection reports is achieved.