Mode S Radar Aircraft ID Verification
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Solution Overview
Problem
The existing mode S secondary surveillance radar systems have a nominal error rate of 10−7 in the CRC function, which can lead to the preparation of erroneous aircraft IDs in target reports, posing a safety risk in air traffic control due to the reliance on a single acquired ID without verification.
Innovation Solution
A mode S secondary surveillance radar that includes a verifier to determine the correctness of acquired aircraft IDs by storing and matching IDs associated with mode S addresses in memory, ensuring only correct IDs are used for preparing target reports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the radar system relies on a single acquired aircraft ID without verification, then the processing speed and simplicity are improved, but the reliability of aircraft ID acquisition deteriorates due to the nominal error rate of 10^-7 in the CRC function
Solution Approach 1:
The patent implements a feedback mechanism where the verifier compares newly acquired aircraft IDs with previously stored IDs associated with the same mode S address. This feedback loop ensures that only consistent, verified IDs are accepted, resolving the contradiction by adding reliability checks without significantly impacting processing speed.
Solution Approach 2:
The system performs preliminary verification by storing aircraft IDs in advance and using them for comparison before finalizing target reports. This preliminary action of storing and comparing IDs proactively prevents erroneous IDs from being used, thereby improving reliability while maintaining efficient processing.
2Reliability
If the radar system implements verification by storing and matching multiple aircraft IDs, then the reliability of aircraft ID acquisition is improved, but the device complexity increases due to additional memory storage and comparison operations
Solution Approach 1:
The patent uses a simple copying and comparison approach where acquired aircraft IDs are stored in memory and subsequent IDs are compared against these stored copies. This method improves reliability through verification while avoiding complex verification algorithms, thus minimizing the increase in device complexity.
Solution Approach 2:
The verifier component performs self-service by automatically comparing newly acquired IDs with stored IDs without requiring external intervention or complex processing. This self-service mechanism enhances reliability while keeping the system architecture simple and the added complexity minimal.
3Reliability
If the radar system performs verification of aircraft IDs in real-time scans, then the safety of air traffic control is improved, but the loss of time increases due to additional verification operations in each scan
Solution Approach 1:
The patent implements periodic verification where aircraft IDs are compared at regular intervals (each scan) rather than continuously. This periodic action ensures real-time safety verification while minimizing time loss by not performing verification operations more frequently than necessary.
Solution Approach 2:
The verification process skips unnecessary operations by directly comparing newly acquired IDs with stored IDs using simple equality checks. This approach rushes through the verification process efficiently, ensuring safety without significant time loss in each scan operation.
Data Source
AI summary
A transmitter (13) operates in an immediate scan after an initial acquisition or detection of an altered aircraft ID by a changed flight status, to transmit to an aircraft a sequence of interrogation signals requesting an aircraft ID transmission, a verifier (17) operates upon acquisition of a reply signal including an aircraft ID transmitted from a transponder on the aircraft, to store in a memory (17a) a mode S address assigned to the aircraft and the aircraft ID in an associating manner, and upon an occurrence of a storage of aircraft IDs associated with the mode S address in the memory (17a), to determine whether or not the aircraft ID is correct, depending on whether or not the aircraft IDs have a match therein, and a report generator (18) operates upon a determination for the aircraft ID to be correct, to prepare a target report using the aircraft ID.