Nested Sonar Antenna Design for Volume Reduction
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Solution Overview
Problem
The bulkiness and mass of sonar subassemblies, particularly the antenna, pose challenges in anti-submarine warfare due to increased acoustic discretion of modern submarines, limiting mission duration and requiring complex, unreliable articulated arms for low-frequency operation.
Innovation Solution
An omnidirectional sonar antenna design where elementary emission rings and hydrophones are nested, reducing volume and mass, and using a computer for robust adaptive processing to enhance directivity and signal-to-noise ratio, eliminating the need for articulated arms and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the operating frequency is lowered to improve acoustic discretion detection, then the detection capability against modern submarines is improved, but the dimensions and mass of the antenna increase
Solution Approach 1:
The patent applies nesting by placing hydrophones inside the emission rings structure. The hydrophones are positioned within the volume occupied by the emission rings, allowing the receiving function to be integrated within the transmitting structure. This nested arrangement enables low-frequency operation with reduced mass compared to conventional separate structures.
2Reliability
If the operating frequency is lowered to improve acoustic discretion detection, then the detection capability against modern submarines is improved, but the dimensions and volume of the antenna increase
Solution Approach 1:
The patent applies nesting by placing hydrophones inside the emission rings structure. The hydrophones are positioned within the volume occupied by the emission rings, allowing the receiving function to be integrated within the transmitting structure. This nested arrangement enables low-frequency operation with reduced volume compared to conventional separate structures.
Solution Approach 2:
The patent merges the transmitting and receiving functions into a single integrated antenna structure. The emission rings and hydrophones are combined in space, with hydrophones positioned within the emission rings volume. This merging eliminates the need for separate transmitting and receiving structures, reducing overall antenna volume.
3Reliability
If articulated arms are used to carry hydrophones for low-frequency operation, then the acoustic performance is maintained, but the device complexity and reliability are worsened
Solution Approach 1:
The patent extracts the hydrophones from the articulated arm structure and integrates them directly into the emission rings. This eliminates the need for complex articulated arms while maintaining the low-frequency acoustic performance. The hydrophones are positioned within the emission rings volume, removing the mechanical complexity of deployable arms.
Solution Approach 2:
The patent replaces the mechanical articulated arm system with a fixed integrated structure. Instead of using movable arms to position hydrophones, the hydrophones are directly integrated within the emission rings structure. This substitution eliminates mechanical complexity and improves reliability while maintaining acoustic performance.
4Reliability
If the antenna dimensions are increased to maintain acoustic performance at low frequency, then the detection capability is improved, but the ability to house the sonar inside the helicopter is worsened
Solution Approach 1:
The patent applies nesting by placing hydrophones inside the emission rings structure. This nested arrangement allows the receiving function to be integrated within the transmitting structure volume, enabling low-frequency operation with compact dimensions that can be housed inside the helicopter.
Solution Approach 2:
The patent merges the transmitting and receiving functions into a single integrated antenna structure. This merging eliminates the need for separate transmitting and receiving structures, reducing overall antenna volume to fit within helicopter constraints while maintaining low-frequency acoustic performance.
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
The design reduces the bulk and mass of sonar subassemblies while maintaining acoustic performance, improving reliability and extending mission duration by optimizing directivity and signal processing, and allowing the sonar to be used on various platforms, including drones.
Implementation Method 1
elementary sound wave emission rings (21) formed around the axis (20)
Implementation Method 2
hydrophones (22) distributed in rings formed around the axis (20)
Data Source
Figure 1
Figure 2a~2b
Figure 2c~2d
AI summary
The invention relates to a compact omnidirectional antenna for a dipping sonar. The antenna (40) includes a plurality of basic transmission rings (21) formed around a longitudinal axis of the antenna (40) and a plurality of hydrophones (22) distributed around the longitudinal axis, the antenna (40) being intended for being dipped in water, the hydrophones (22) being separate from the basic transmission rings (21), the hydrophones (22) and the basic transmission rings (21) being secured to the antenna (40). According to the invention, the basic transmission rings (21) and the hydrophones (22) are interlocked along a same height (H) measured according to the longitudinal axis.