Underwater Vehicle Electromagnetic Disturbance Analysis
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Solution Overview
Problem
Conventional sonar detection methods for underwater targets, such as shipwrecks, are prone to false alarms due to ocean sediment and seabed terrain, and are expensive and vulnerable to marine background noise, making it difficult to detect targets hidden in noise across large sea areas.
Innovation Solution
A sequence time window amplitude-phase-frequency characteristics analysis method for underwater vehicle power frequency electromagnetic field disturbance, which involves determining background field data, measuring data when an underwater vehicle passes, performing short-time Fourier transforms and Fourier sliding window decomposition, and analyzing amplitude and phase spectra to detect disturbance signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sonar detection method is used to detect underwater targets, then the orientation of target can be sensed by receiving sonar echo, but false alarm detections occur due to disturbance from undulating terrain of seabed and ocean sediment
Solution Approach 1:
The patent replaces the acoustic sonar detection system with an electromagnetic field-based detection system. Specifically, it uses power frequency electromagnetic fields generated by underwater vehicles to induce currents in ferromagnetic targets, detecting the resulting electromagnetic responses. This substitution eliminates the fundamental problem of acoustic wave interference from seabed terrain and ocean sediment that causes false alarms in sonar systems.
Solution Approach 2:
The patent changes the detection parameter from acoustic echo reception to electromagnetic field interaction. By utilizing the power frequency electromagnetic fields naturally generated by underwater vehicles and their interaction with ferromagnetic targets, the system detects targets through electromagnetic induction rather than acoustic reflection. This parameter change fundamentally avoids the false alarm issue caused by acoustic disturbance from undulating seabed terrain.
2Measurement precision
If acoustic detection means is used to detect underwater targets, then detection can be performed, but it is expensive and vulnerable to interference of marine background noise
Solution Approach 1:
The patent replaces the acoustic detection means with an electromagnetic detection system. It utilizes power frequency electromagnetic fields to interact with ferromagnetic underwater targets, detecting them through electromagnetic induction. This substitution eliminates vulnerability to marine background noise that interferes with acoustic detection, as electromagnetic fields at power frequency are not affected by ambient marine acoustic noise.
3Length of stationary object
If acoustic detection means is used to detect underwater targets hidden under ocean background noise across long distance, then detection is attempted, but it has been difficult to achieve effective detection
Solution Approach 1:
The patent replaces acoustic detection with electromagnetic field-based detection using power frequency electromagnetic fields. These fields can penetrate seawater effectively and interact with ferromagnetic targets at long distances. The electromagnetic induction mechanism allows detection of targets hidden under ocean background noise across long distances with improved accuracy, overcoming the limitations of acoustic detection in such conditions.
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 effectively suppresses background clutter interference and detects disturbance signals caused by underwater vehicles, with disturbance signals being significantly stronger than background signals, leading to improved detection accuracy.
Implementation Method 1
The power frequency electromagnetic field has high penetration performance, and can penetrate the sea to act on an underwater ferromagnetic target
Implementation Method 2
Under the action of the power frequency electromagnetic field (waves), the target generates a distorted signal, thereby enabling an underwater ferromagnetic target to be detected
Data Source
AI summary
A sequence time window amplitude-phase-frequency characteristics analysis method and system for underwater vehicle power frequency electromagnetic field disturbance are provided. The method includes: establishing a power grid dipole group model, emulating and calculating to obtain background field intensity data of a test location, and constructing an emulated background field database; acquiring measured background field data, comparing the emulated data with the measured data, and providing a relative error; calculating a background field intensity and underwater vehicle target disturbance under the action of the above dipole group, and establishing a measured target signal database; and performing actual measurement according to an underwater vehicle motion and detection topology, performing a Fourier transform and Fourier sliding window decomposition after acquiring original data, and acquiring an amplitude spectrum and a spectrogram of an underwater vehicle target disturbance signal.