Circular Phased Array Sonar for Single-Ping 3D Imaging
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Solution Overview
Problem
Traditional sonar systems face limitations in achieving high-resolution, efficient, and scalable 3D imaging underwater due to complex electronics and beamwidth requirements, particularly with Mills Cross and square phased arrays.
Innovation Solution
A circular phased array is used instead of traditional square arrays, reducing the number of elements needed and simplifying electronics, while maintaining beam steering capabilities, and employing a wide-angle projector for comprehensive coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a square phased array is used to achieve narrow beamwidth in two directions, then 3D imaging capability is improved, but the number of elements increases to N2, resulting in complex and expensive electronics
Solution Approach 1:
The patent applies a circular array geometry instead of a square array. The circular arrangement of N elements provides rotational symmetry that enables narrow beamwidth in all azimuth directions while maintaining a manageable number of elements. The circular geometry naturally distributes elements to achieve omnidirectional coverage without requiring N2 elements as in a square configuration.
Solution Approach 2:
The patent transitions from a two-dimensional square array to a one-dimensional circular array by arranging elements along the circumference. This dimensional reduction allows achieving similar 3D imaging capability with fewer elements, as the circular geometry provides inherent rotational coverage that eliminates the need for a full 2D grid of elements.
2Device complexity
If a linear array is used, then the number of elements is reduced to N, but the beamwidth becomes wide in the perpendicular direction, limiting 3D imaging capability
Solution Approach 1:
The circular array geometry provides rotational symmetry that narrows the beamwidth in the azimuth direction compared to a linear array, while maintaining the advantage of using only N elements. The curved circular arrangement distributes the N elements around a circumference, creating narrower beams in all directions around the array rather than having a wide perpendicular beamwidth as in linear configurations.
3Measurement precision
If more elements are added to increase resolution, then imaging precision is improved, but the electronic complexity and cost increase significantly
Solution Approach 1:
The circular array geometry provides more efficient use of elements for achieving resolution. By arranging N elements along a circular circumference, the system achieves omnidirectional coverage and narrow beamwidth simultaneously, providing better resolution in all directions compared to linear or square arrangements with the same number of elements.
Solution Approach 2:
The circular array configuration provides multi-functional capability: it achieves 3D imaging, provides rotational symmetry for omnidirectional coverage, and maintains a manageable number of elements. This universal design satisfies multiple requirements (resolution, coverage, complexity control) simultaneously, making the system more efficient than specialized configurations.
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 circular array design achieves high-resolution, single-ping 3D imaging with simplified electronics, reduced cost, and improved scalability, enhancing underwater mapping and navigation applications.
Implementation Method 1
A 3D imaging sonar system includes a wide opening angle projector that transmits at least one pulse of acoustic energy
Implementation Method 2
The echoes from this pulse are received by the circular array
Implementation Method 3
The range to each detected high reflectivity object is found by the time of flight
Data Source
AI summary
A system and method for generating three-dimensional (3D) images using sonar technology comprises a circular phased array to create 3D point clouds from the echoes of a single sonar ping and may be configured to measure Doppler shift. The circular phased array is a circular receiver array that is combined with a single, wide opening angle projector that transmits at least one pulse of acoustic energy. The echoes from this pulse are received by the circular array. The signals from the receiver elements are combined using Delay and Sum beamforming processes to perform spatial filtering with resolution as discussed above. The system and method combine advantages of Mills Cross systems and square arrays, providing high-resolution, instantaneous 3D imaging employing a 1D array, leading to a more efficient and scalable design.