Monopulse Radar Stand-by Channel Fixed Antennas
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Solution Overview
Problem
Monopulse Secondary Surveillance Radars with dual redundant architecture often miss unsolicited squitter transmissions due to the rotation of the antenna, leading to disrupted information update rates and variable reception ranges depending on the antenna's azimuth position.
Innovation Solution
Incorporating a dual redundant interrogator with a stand-by TR/RX channel connected to fixed sectorised antennas, allowing for the reception and processing of unsolicited squitter transmissions from aviation radio systems, such as ADS-B, independent of the antenna's azimuth position, and using low noise amplifiers to enhance reception range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rotating antenna with three RF paths (sum, diff, omni) is used for active interrogation, then the radar can perform monopulse tracking and active target interrogation, but unsolicited squitter transmissions are missed due to antenna rotation and dissimilar antenna diagrams
Solution Approach 1:
The antenna system is segmented into two independent parts: a rotating monopulse antenna for active interrogation and fixed sectorised antennas for receiving unsolicited transmissions. This segmentation allows each antenna type to be optimized for its specific function without interference from the other.
Solution Approach 2:
The stand-by TR/RX channel is given multi-functionality by connecting it to fixed sectorised antennas, enabling it to receive both unsolicited squitter transmissions and potentially support active interrogation if needed. This universal design maximizes resource utilization.
2Adaptability or versatility
If the stand-by TR/RX channel is left idle and connected to dummy loads, then the dual redundant architecture maintains simplicity, but the reception capability for unsolicited transmissions is not utilized
Solution Approach 1:
The fixed sectorised antennas are merged with the stand-by TR/RX channel, combining the redundancy capability with enhanced reception functionality. This merging allows the stand-by channel to serve dual purposes: maintaining system redundancy and receiving unsolicited transmissions.
Solution Approach 2:
The stand-by TR/RX channel serves itself by being equipped with fixed sectorised antennas, enabling it to independently receive unsolicited transmissions without requiring additional active components or complex switching mechanisms.
3Measurement precision
If fixed sectorised antennas are connected to the stand-by TR/RX channel, then unsolicited squitter transmissions can be received independent of azimuth position, but the system complexity increases
Solution Approach 1:
Different antenna types are assigned to different functional requirements: the rotating monopulse antenna provides directional precision for active tracking, while fixed sectorised antennas provide omnidirectional coverage for unsolicited transmissions. Each antenna type is optimized for its local quality requirements.
Solution Approach 2:
Instead of using the rotating antenna for receiving unsolicited transmissions, the invention inverts the approach by using fixed antennas for reception while the rotating antenna focuses on active interrogation. This inversion resolves the contradiction between rotation and continuous reception.
Data Source
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AI summary
The inventions relates to a monopulse secondary surveillance radar comprising: - a rotating antenna (10) for transmitting interrogations and receiving corresponding replies from external transponders, - a dual redundant interrogator (30) comprising two parallel TR/RX channels (32A,32S), each TR/RX channel comprising a transmitter and a receiver, - a changeover equipment, the status of which defines which one of the two TR/RX channels acts as the active (32A) or as the stand-by TR/RX channel (32S) by connecting the rotating antenna (10) with the active TR/RX channel (32A), characterized in that the monopulse secondary surveillance radar further comprises a plurality of fixed sectorised antennas (40) that together are capable to cover the complete azimuth, and that the stand-by TR/RX channel (32S) can be switchably connected to the fixed sectorised antennas (40), and that the stand-by TR/RX channel (32S) is capable to receive and process unsolicited squittered transmissions from aviation radio systems received via the sectorised antennas (40).