Phase-Conjugate Pseudo Sound Source for Buried Object Detection
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Solution Overview
Problem
Conventional sonar devices face difficulties in detecting buried objects in the ocean due to the complex interference of transverse, lateral, and longitudinal wave components at the water-seabed boundary, requiring extensive scanning time and posing safety risks when detecting explosive objects.
Innovation Solution
A phase-conjugate pseudo sound sweeping system that transmits scanning sound waves using active phase conjugation, allowing them to converge on the detection object from above, and employs passive phase conjugation to extract reflected waves, enabling detection without being constrained by the object's positional relationship and ensuring safety by avoiding direct contact with explosive objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sound wave is emitted vertically downward to avoid transverse and lateral wave components, then wave interference is reduced, but the search time becomes enormous and safety risks arise when detecting explosive objects
Solution Approach 1:
Instead of emitting sound waves vertically downward from above the search area, the invention inverts the approach by emitting sound waves from the sides at oblique angles. The phase conjugation technique then focuses these obliquely incident waves onto the target, achieving both reduced interference and improved safety while maintaining detection effectiveness.
Solution Approach 2:
The invention changes the incident angle parameter from vertical (0 degrees) to oblique angles. By controlling the sound wave incidence at specific oblique angles and using phase conjugation, the system achieves focused energy concentration on the target while avoiding the generation of transverse and lateral wave components that occur with vertical incidence.
2Ease of operation
If a sound wave is emitted vertically downward, then transverse and lateral wave components are not generated, but the method cannot detect explosive objects safely and requires unlimited scanning time
Solution Approach 1:
The phase conjugation technique provides universal applicability for detecting different types of objects (metallic, non-metallic, buried, surface) regardless of their position or composition. The system can detect objects anywhere in the search area by adjusting the phase conjugation parameters, making the method highly versatile while maintaining operational simplicity.
3Measurement precision
If conventional sonar methods are used to detect buried objects, then detection is possible, but complex interference from transverse, lateral, and longitudinal wave components makes detection difficult
Solution Approach 1:
The invention extracts only the useful longitudinal wave component by using phase conjugation with oblique incidence, effectively removing the problematic transverse and lateral wave components. This extraction of the desired wave mode simplifies the detection process and improves measurement precision by eliminating complex interference patterns.
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
This method allows for efficient detection of objects without the limitations of conventional scanning times and safety hazards, effectively identifying buried objects through phase-conjugate pseudo sound source sweeping.
Implementation Method 1
transmitting a scanning sound wave generated by performing active phase conjugation (time reversal processing) on a phase-conjugate wave in a time domain based on an acoustic signal emitted from a pseudo sound source, by utilizing a feature that the scanning sound wave converges on the pseudo sound source which is a generation source of the acoustic signal
Implementation Method 2
causing the scanning sound wave to converge on a detection object (T) in the detection area from above the detection object (T) in a propagation space
Implementation Method 3
a monitoring unit which performs passive phase conjugation so as to extract from the sound wave in the propagation space a reflected sound wave which is reflected at the detection object
Implementation Method 4
extract from the sound wave in the propagation space a reflected sound wave which is reflected at the detection object
Data Source
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AI summary
An object is detected without being constrained by the positional relationship between the object and the detecting position. A detection device includes a pseudo sound source and a monitoring unit. The pseudo sound source generates a scanning sound wave of a phase-conjugate wave in the time domain based on an acoustic signal by performing active phase conjugation, and causes the scanning sound wave to converge on the detection object from the above thereof within the propagation space by utilizing a feature that the scanning sound wave converges on the pseudo sound source which is the generation source of the acoustic signal. The monitoring unit extracts a reflected sound wave which is reflected at the detection object from the sound wave in the propagation space by performing passive phase conjugation. The detection object is detected based on presence or absence of the extracted reflected wave.