Acoustic Region Mapping Using Synthetic Array Correlation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for mapping the ocean floor face challenges in achieving high mapping resolution while keeping operational costs low, particularly due to the increasing difficulty of acoustic imaging at greater depths and the high costs associated with using surface vessels or subsea vehicles.
Innovation Solution
A method involving a signal transmitter and receiver that move relative to a target region, transmitting a continuous probing signal with a predefined bandwidth of noise, and correlating the response signal to generate a map of correlation strength values, utilizing temporal information to create a synthetic array that suppresses signals with different path lengths, allowing for high-resolution mapping with low-cost hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pulse-based mapping systems are used, then mapping capability is achieved, but roundtrip time increases with propagation distance making acoustic imaging increasingly difficult for surfaces at greater depths
Solution Approach 1:
The patent employs periodic transmission of acoustic signals with known time sequences, allowing the system to continuously probe the target region and accumulate signal data over multiple periods. This periodic action enables the system to overcome the increasing roundtrip time by integrating information from repeated signal transmissions, maintaining mapping capability at greater depths.
Solution Approach 2:
The system implements continuous signal transmission and reception, where the acoustic probing signal is continuously sent towards the target region and the response signal is continuously received and processed. This continuity allows the system to maintain constant mapping operation despite increasing propagation delays, as useful information is accumulated continuously rather than in discrete pulses.
2Measurement precision
If surface vessels with continuous wave or frequency modulated multi-beam acoustic arrays are used, then imaging capability at greater depths is improved, but operational costs become high and achievable imaging resolution remains relatively low
Solution Approach 1:
The patent creates a virtual copy of the acoustic array by using signal processing to synthesize additional receiver elements. Instead of physically deploying a large multi-beam acoustic array on a surface vessel, the system uses a single or few physical receivers and generates virtual receivers through correlation processing, significantly reducing hardware complexity and operational costs while achieving comparable imaging capability.
Solution Approach 2:
The system changes the temporal parameters of the acoustic signals by using long sequences with specific autocorrelation properties. By carefully selecting the time sequence characteristics (long duration, narrow autocorrelation peak), the system achieves high range resolution without requiring complex hardware, transforming the problem from a spatial array design to a temporal signal design.
3Measurement precision
If subsea vehicles are brought close to the seabed, then mapping resolution is improved, but operational costs become high due to required presence of operators and support vessel
Solution Approach 1:
The system enables self-service operation where the acoustic signal processing and mapping generation are performed automatically by the system itself without requiring external operators or support vessels. The correlation processing and map generation are executed autonomously, allowing the system to operate independently and eliminate the need for costly human intervention and support infrastructure.
Solution Approach 2:
The patent replaces the mechanical approach of physically positioning vehicles close to the seabed with a signal processing approach. Instead of mechanically moving the receiver close to the target, the system uses acoustic signal correlation to achieve virtual proximity, substituting mechanical positioning with electromagnetic (acoustic) field processing.
4Measurement precision
If long sequences with narrow autocorrelation peak are used, then range resolution is improved, but signal transmission time increases
Solution Approach 1:
The system performs preliminary processing of the received signal by correlating it with the known transmitted sequence before final map generation. This preliminary correlation action extracts the range information early in the processing chain, allowing the system to use long sequences for high resolution while efficiently managing transmission time through pre-computed correlation templates.
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 method enables high-resolution mapping of underwater surfaces with reduced operational costs by using a synthetic array that leverages temporal information, achieving accurate imaging of subsea surfaces and other applications with simple and cost-effective acquisition hardware.
Implementation Method 1
transmitting, with the signal transmitter, a probing signal towards the target region... continuously receiving, with the signal receiver, a response signal composed of a plurality of signal components that result from scattering of the probing signal by respective ones of the portions of the target region
Implementation Method 2
Pulse-based mapping systems rely on the round-trip time for the acoustic signals propagating through the water
Data Source
AI summary
A method and system for mapping a target region (60) of space with signal scatterers. The method involves moving a signal transmitter (26) and/or signal receiver (46) along a respective trajectory (34, 54) relative to the target region, and meanwhile transmitting a probing signal (62) towards the target region, this probing signal including a time sequence of noise (70) with a predefined bandwidth, receiving a response signal (76) composed of components resulting from scattering of the probing signal (62) by respective portions of the target region, and repeatedly determining positions (QT, QR) of the transmitter and/or receiver. The method further involves transforming the probing signal (62) into multiple test signals, each test signal being associated with a propagation path via a portion of the target region, and correlating each of the test signals with the response signal (76) in the time domain, to generate a map of correlation strength values associated with the portions of the target region.