Sensor Receiver Null Steering for Marine Noise Discrimination
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Solution Overview
Problem
Geophysical surveying in marine environments faces challenges in discriminating between reflected signals and noise sources due to complex acoustic interactions at the water-air interface and environmental noise, which complicates signal detection and interpretation.
Innovation Solution
The use of multi-component sensors, including co-located hydrophones and particle motion sensors, combined with coordinate rotation and signal processing techniques to create nulls in sensor sensitivity, effectively discriminates against noise sources and enhances signal discrimination by aligning sensor directivity patterns to minimize noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multi-component sensors and coordinate rotation techniques are used to create nulls in sensor sensitivity, then noise discrimination capability is improved, but device complexity increases
Solution Approach 1:
The sensor system is divided into multiple independent sensor components (e.g., vertical, north-south, east-west sensors) that can be individually controlled. Each sensor component responds to acoustic signals from different directions, allowing the system to create directional nulls by selectively combining or suppressing signals from specific sensors based on the noise source location.
Solution Approach 2:
The system dynamically adjusts sensor sensitivity in different directions by applying coordinate rotations and time-varying weighting factors to sensor outputs. This allows the null direction to be steered dynamically toward moving noise sources while maintaining sensitivity to seismic signals from other directions.
2Measurement precision
If sensor directivity patterns are aligned to minimize noise interference, then signal discrimination accuracy is improved, but ease of operation deteriorates
Solution Approach 1:
The system automatically determines the location of noise sources using signals detected by the sensor array, then autonomously steers nulls toward these identified noise sources without requiring manual intervention. The system self-adjusts the coordinate rotations and weighting factors based on real-time noise source localization.
Solution Approach 2:
The system continuously monitors sensor outputs to detect noise sources, calculates appropriate null steering parameters, and applies coordinate rotations to achieve the desired directivity pattern. This closed-loop feedback mechanism automatically adapts the sensor array response to current environmental 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 approach significantly reduces noise interference, allowing for effective discrimination between seismic acoustic signals and noise, improving the accuracy of geophysical data acquisition and enabling repeat surveys and passive monitoring of subsurface activity.
Implementation Method 1
the output from hydrophones sensitive to the pressure perturbation from the acoustic signal
Implementation Method 2
the output of a particle motion sensor sensitive to the velocity of a particle for example, a geophone
Data Source
AI summary
Sensor receiver nulls and null steering. One example embodiment is method in which a direction from a sensor position to a noise source is determined. A coordinate rotation is applied to a first set of signal values, wherein each signal value of the first set of signal values is based on an output of a corresponding component of a three-component particle motion sensor at the sensor position. The applying generates a rotated set of signal values. The coordinate rotation comprises a coordinate rotation transforming a first set of coordinate axes to a second set of coordinate axes, wherein the first set of coordinate axes has each coordinate axis aligned with a corresponding component of the three-component particle motion sensor at the sensor position, and the second set of coordinate axes comprises a first axis pointed in a direction opposite the direction from the sensor position to the noise source.