Underwater Detection Device Range Side Lobe Suppression
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Solution Overview
Problem
Underwater detection devices face issues with range side lobes appearing due to seabeds, leading to false images and difficulty in detecting fish shoals near the seabed, as these devices perform pulse compression, reducing axial resolving power and causing mistaken identification of seabed features as target objects.
Innovation Solution
An underwater detection device with a range side lobe suppression module that determines a suppression range, calculates suppression values, and performs calculations to suppress range side lobes in the pulse-compressed signals, enhancing the clarity of seabed images by differentiating between target echoes and seabed reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If pulse compression process is performed to increase detection distance, then detection distance is improved, but range side lobes appear causing false images and reducing measurement precision
Solution Approach 1:
The patent extracts and removes the harmful range side lobe components from the pulse-compressed signal while preserving the main lobe information. This is achieved through detecting range side lobes based on their characteristic features (lower amplitude, specific temporal position relative to main lobe) and selectively eliminating them, thereby maintaining detection distance improvement while restoring measurement precision.
Solution Approach 2:
The patent applies different processing qualities to different parts of the signal: the main lobe components are preserved with high fidelity for accurate target detection, while the range side lobe components are selectively suppressed or removed. This local differentiation allows the system to maintain high axial resolving power in critical regions while preserving overall detection distance capability.
2Duration of action of moving object
If transmission pulse length is lengthened to increase detection distance, then detection distance is improved, but axial resolving power is reduced
Solution Approach 1:
The patent changes the temporal parameters of the transmitted pulse by applying frequency modulation (chirp modulation) to extend the pulse duration for increased detection distance. The frequency modulation allows the pulse to carry more energy over extended time while the subsequent pulse compression process restores the axial resolving power by re-compressing the spread spectrum signal back to a sharp peak.
3Measurement precision
If pulse compression is performed to maintain axial resolving power, then axial resolving power is improved, but range side lobes cause false identification of target objects
Solution Approach 1:
The patent converts the harmful effect of range side lobes into a beneficial detection mechanism by using their predictable characteristics (consistent amplitude ratio relative to main lobe, specific temporal positioning) as fingerprints to identify and remove them. The range side lobes, which were previously causing false targets, are now systematically detected and eliminated based on their inherent structural properties, thereby improving target identification accuracy.
4Measurement precision
If range side lobes are suppressed to improve target detection accuracy, then measurement precision is improved, but detection device complexity increases
Solution Approach 1:
The patent applies partial suppression action by selectively removing only the range side lobe components that meet specific detection criteria (amplitude threshold relative to main lobe, temporal position constraints) rather than applying uniform suppression across the entire signal. This partial action approach achieves sufficient target detection accuracy improvement while avoiding the excessive complexity of comprehensive signal processing methods.
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 solution effectively suppresses range side lobes, allowing for clearer detection images near the seabed, reducing false identifications and improving the accuracy of seabed depth determination and fish shoal detection.
Implementation Method 1
transmitting underwater an ultrasonic pulse signal that is frequency-modulated
Implementation Method 2
receiving an echo signal corresponding to the transmitted signal
Implementation Method 3
a received echo signal and a replica waveform of the transmitted signal is correlation-processed to perform a pulse compression of the received signal
Data Source
AI summary
An underwater detection device includes a transceiver module for transmitting underwater an ultrasonic pulse signal that is frequency-modulated and receiving an echo signal corresponding to the transmitted signal, a pulse compression module for pulse-compressing the signal received by the transceiver module and outputting a signal pulse-compressed, a suppression range determining module for determining a suppression range where a range side lobe suppression process is performed for the pulse-compressed signal, an echo determining module for determining whether the data of the pulse-compressed signal at each depth corresponding to a range side lobe, a suppression value determining module for determining a suppression value for the data of the pulse-compressed signal at each depth, a suppression conducting module for performing a calculation to suppress the range side lobe based on the suppression value for the data determined to be data of the pulse-compressed signal corresponding to the range side lobe by the echo determining module among a plurality of data of the pulse-compressed signals that fall into the suppression range, and a display processing module for generating a signal for display based on the signal outputted from the suppression conducting module to display a generated signal as detected information.