Forward Scattering Wave Target Detection via Phase Conjugation
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Solution Overview
Problem
Existing underwater target searching methods face challenges in accurately locating targets due to insufficient backward scattering waves from small targets or low-frequency sound waves, and the difficulty in distinguishing forward scattering waves from traveling waves in shallow water environments.
Innovation Solution
A target searching device and method that utilize forward scattering waves mixed with traveling waves, employing subtraction processing to separate the waves, followed by passive-phase conjugate processing and autocorrelation processing to generate and compare signals, allowing for accurate target detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If backward scattering waves are used for target searching, then target detection can be performed, but sufficient backward scattering waves cannot be obtained from small targets or low-frequency sound waves, making accurate target searching impossible
Solution Approach 1:
The patent inverts the conventional approach by using forward scattering waves instead of backward scattering waves for target detection. Forward scattering waves naturally have higher intensity than backward scattering waves, especially for small targets and low-frequency sound waves. The method receives forward scattering waves that travel from the sound source through the target to the receiver, eliminating the need for strong backward scattering that is insufficient for small targets.
Solution Approach 2:
The patent changes the detection parameter from backward scattering wave intensity to forward scattering wave characteristics. By utilizing the higher intensity forward scattering waves and applying phase conjugate processing to separate them from traveling waves, the system achieves accurate target detection where conventional backward scattering methods fail.
2Quantity of substance
If forward scattering waves are used for target searching, then higher signal level is obtained, but forward scattering waves are hidden in traveling waves, making accurate target searching difficult
Solution Approach 1:
The patent extracts the forward scattering wave signal from the mixed signal containing both traveling waves and forward scattering waves. By using phase conjugate processing, the system separates the forward scattering waves from the dominant traveling waves, making the target detection possible despite the lower intensity of the scattered component.
Solution Approach 2:
The patent introduces phase conjugate processing as an intermediary technique to separate the forward scattering waves from traveling waves. This mathematical processing acts as a mediator that isolates the target-related signal from the background noise of direct traveling waves, enabling accurate target detection.
3Adaptability or versatility
If conventional searching methods are used in shallow water, then reflected waves from sea surface or seabed can be handled, but these reflected waves make it difficult to search targets accurately
Solution Approach 1:
The patent segments the received signal into distinct components: traveling waves and forward scattering waves. By applying phase conjugate processing, the system separates these components and uses only the forward scattering waves for target detection, eliminating the interference from reflected waves that plague conventional methods in shallow water environments.
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 target detection by matching the autocorrelation function of incident sound waves with the passive-phase conjugated signal of forward scattering waves, effectively overcoming limitations in existing methods by utilizing the similarity between these signals to determine the target's position.
Implementation Method 1
a sound source (3) for transmitting a sound wave into the propagation space (1)
Implementation Method 2
a forward scattering wave scattering forward from the target (2)
Implementation Method 3
a subtraction processing device (7) for separating the forward scattering wave (5) by subtracting the traveling wave (4) directly traveling towards the transducer array (6) from a mixed wave of the forward scattering wave (5) and the traveling wave (4)
Implementation Method 4
a passive-phase conjugate processing device (8) for generating a passive-phase conjugated signal of the forward scattering wave (5) by performing passive-phase conjugate processing on the forward scattering wave (5)
Implementation Method 5
an autocorrelation processing device (9) for generating an autocorrelation processed signal of the traveling wave (4) by performing autocorrelation processing on the traveling wave (4)
Implementation Method 6
a correlation device (10) for judging a similarity between the autocorrelation processed signal and the passive-phase conjugated signal
Data Source
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AI summary
The target searching device includes: a sound source which transmits a sound wave into a propagation space; a transducer array placed in an area to receive a forward scattering wave which scatters forward from the target within the propagation space; a subtraction processing device which subtracts a traveling wave directly traveling towards the transducer array from a mixed wave of the forward scattering wave and the traveling wave so as to separate the forward scattering wave; a passive-phase conjugate processing device which performs passive-phase conjugate processing on the forward scattering wave separated by the subtraction processing device so as to generate a passive-phase conjugated signal of the forward scattering wave; an autocorrelation processing device which performs autocorrelation processing on the traveling wave to generate an autocorrelation processed signal of the traveling wave; and a correlation device which judges a similarity between the autocorrelation processed signal and the passive-phase conjugated signal.