Sonar Range Estimation via Sidelobe Compensation
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Solution Overview
Problem
Current sonar systems face inaccuracies in detecting the bottom of a body of water due to false bottoms caused by strong inhomogeneities or life layers, leading to incorrect range and velocity measurements, and fail to account for signal losses from water absorption and spreading.
Innovation Solution
A method and system for estimating the range to a water surface using acoustic signals, incorporating a sonar system with multiple transducers and a signal processor that compensates for sidelobe coupling by performing linear transformations on received echoes to accurately determine the distance, minimizing false bottom detection and accounting for signal losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If simple threshold comparison is used for bottom detection, then the system is easy to operate, but false bottoms are detected due to strong inhomogeneities or life layers
Solution Approach 1:
The patent introduces an intermediary approach by using multiple beam data and signal processing algorithms as a mediator between the simple threshold comparison and the complex reality of acoustic reflections. The system processes echoes from multiple beams simultaneously, using algorithmic analysis to distinguish true bottom reflections from false bottoms caused by inhomogeneities or life layers, thereby maintaining operational simplicity while improving detection accuracy.
Solution Approach 2:
The patent transitions from one-dimensional threshold comparison to multi-dimensional analysis by utilizing echoes from multiple beams (at least two beams) simultaneously. This dimensional expansion allows the system to analyze the spatial distribution and characteristics of reflections across different beam angles, enabling differentiation between true bottom and false bottom reflections through pattern recognition in the multi-beam echo data.
2Measurement precision
If multiple beams are used to improve measurement accuracy, then velocity components can be measured, but sidelobe coupling causes signal loss and measurement errors
Solution Approach 1:
The patent implements feedback by continuously monitoring the echo data from multiple beams and using signal processing algorithms to identify and compensate for sidelobe coupling effects. The system analyzes the relationship between beams and adjusts the velocity calculations based on the observed interference patterns, effectively feeding back the sidelobe information to correct the measurements and maintain accuracy despite signal loss.
Solution Approach 2:
The patent uses signal processing algorithms as an intermediary to manage the complex interactions between multiple beams. These algorithms act as a mediator that processes the raw echo data, separates the useful signal from the interfering sidelobe components, and produces accurate velocity measurements despite the presence of signal loss from sidelobe coupling.
3Measurement precision
If bottom range pulses are interleaved with current velocity pulses, then vessel velocity can be determined, but the pulse duration must be extended to fully ensonify the bottom
Solution Approach 1:
The patent segments the pulse transmission by using multiple shorter pulses instead of one long pulse. By transmitting multiple pulses at different times and processing their echoes separately, the system achieves complete ensonification of the bottom without requiring each individual pulse to be excessively long, thereby maintaining vessel velocity determination accuracy while reducing the duration requirement for each pulse.
Solution Approach 2:
The patent ensures continuity of useful action by interleaving bottom range pulses with current velocity pulses in a continuous monitoring sequence. This allows the system to maintain continuous contact with the bottom while periodically sampling velocity information, ensuring that the bottom remains fully ensonified throughout the measurement process without requiring extended pulse durations.
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 enhances the accuracy of sonar systems by reducing false bottom detection and compensating for signal losses, resulting in improved vessel and water velocity measurements.
Implementation Method 1
receiving a plurality of signals reflected from the surface
Implementation Method 2
The received sound has a Doppler frequency shift proportionate to the relative velocity between the scatters and the transducer
Implementation Method 3
a transducer to generate pulses of sound (which when down-converted to human hearing frequencies sound like 'pings') that backscatter as echoes from plankton, small particles, and small-scale inhomogeneities in the water
Implementation Method 4
compensating for signal losses due to water absorption and spreading
Data Source
AI summary
A system and method of range estimation are disclosed. In one embodiment, the method comprises transmitting beams through a medium towards a surface, receiving reflected signals from the surface, and estimating range to the surfaced based on the reflected signals and an estimate of sidelobe coupling of the beams.