Aircraft Transponder Positioning Using Range and Angle of Arrival
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Solution Overview
Problem
Current systems face challenges in determining the position of a transponder-equipped aircraft outside the range of Secondary Surveillance Radar (SSR) coverage, particularly on the ground, where existing methods like TCAS are limited in range and cannot be used on the ground.
Innovation Solution
A method involving an omni-directional antenna system that transmits interrogation signals, detects reply signals, determines the range and heading of a flying object, and uses angle of arrival to pinpoint its position, ensuring aviation safety by calculating potential collision avoidance measures and updating protection volumes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If TCAS is used for collision avoidance, then mid-air collision prevention is improved, but the system cannot be used on the ground and coverage is limited
Solution Approach 1:
The patent creates a positioning system that serves multiple functions: it can track both manned and unmanned aircraft, operate both in the air and on the ground, and work within or outside SSR coverage. The single ground station with omni-directional antenna performs positioning, collision risk assessment, and protection volume management across all these scenarios.
Solution Approach 2:
The patent divides the surveillance space into protection volumes centered on each manned aircraft, allowing the system to provide targeted collision avoidance for specific aircraft while maintaining overall situational awareness of all flying objects in the area.
2Measurement precision
If three broadcasting stations with omni-directional antennas are used for positioning, then position determination outside SSR range is improved, but transmission time precision requirements increase complexity
Solution Approach 1:
The patent extracts the positioning function from the complex three-station SSR-like system and implements it with a single ground station. By using one station with omni-directional antenna capability and angle of arrival measurement, the system achieves positioning without requiring precise synchronization between multiple transmitters.
Solution Approach 2:
The patent introduces an intermediary measurement method - angle of arrival detection at a single station - that serves as a mediator between the transmitted signal and position determination. This intermediary approach eliminates the need for complex multi-station time synchronization while achieving accurate positioning.
3Area of stationary object
If a single ground station with omni-directional antenna is used for positioning, then ground coverage is improved, but the ability to determine position without SSR assistance must be achieved
Solution Approach 1:
The patent adds the angle of arrival dimension to the traditional range-based positioning. By measuring both the round-trip time (giving range) and the angle of arrival of the reply signal, the single ground station can determine two-dimensional position information without requiring multiple stations or SSR assistance.
Solution Approach 2:
The patent replaces the mechanical/multi-station radar approach with an electronic signal processing approach. The single station uses electronic angle of arrival measurement and signal processing to achieve positioning that would traditionally require multiple physical stations, thereby achieving full ground coverage with simplified hardware.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate positioning of aircraft outside SSR range, ensuring safety by determining the minimum time interval for collision avoidance and implementing corrective actions to prevent mid-air collisions, with full ground coverage.
Implementation Method 1
transmitting an interrogation signal from an omni-directional antenna located at a control station
Implementation Method 2
detecting a reply signal from a transponder of the flying object
Implementation Method 3
detecting an angle of arrival of the reply signal by an antenna arrangement, thereby discriminating between the two possible paths
Data Source
AI summary
A method and apparatus for enhancing aviation safety, ensuring that unmanned aircraft remain well clear of other flying objects, are disclosed. A control station acquires a direction of a path of a flying object and periodically transmits requests to a transponder of the flying object to acquire specific data. Upon receiving a response to a request, a range of the flying object from the control station is determined. Using data acquired from each three consecutive responses, the displacement magnitude, the speed, and angular displacements of the flying object are determined. The method assesses potential crossing of a protection zone surrounding a protected aircraft based on most recent acquired data.