Synthetic Aperture Sonar Phase Correction for Precise Navigation
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Solution Overview
Problem
Current underwater navigation systems face challenges due to coarse bathymetry maps, power consumption, size, and performance issues with synthetic aperture sonar (SAS) systems, particularly at high frequencies and low wavelengths, which limit their effectiveness for precision navigation in complex ocean conditions.
Innovation Solution
The development of high-frequency and low-frequency SAS systems that utilize phase error correction and holographic navigation techniques to improve image generation and navigation capabilities, enabling coherent terrain recognition and navigation by compensating for spatially varying phase errors and using multiple transmitters and receivers to form a full planar synthetic aperture sonar with higher resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-frequency SAS systems are used to improve angular resolution and image quality, then measurement precision is improved, but power consumption increases and system size increases
Solution Approach 1:
The patent changes the operating frequency parameter of the SAS system, demonstrating that both high-frequency and low-frequency systems can achieve effective navigation. By adjusting the frequency parameter and applying phase error correction, the system maintains measurement precision while adapting power consumption to different operational requirements
Solution Approach 2:
The patent implements dynamic phase error correction that adapts to varying ocean conditions and vehicle motion. The system dynamically adjusts correction parameters based on real-time spatially varying phase errors, allowing flexible operation across different frequency ranges and power consumption levels
2Measurement precision
If high-frequency SAS systems are used to improve angular resolution, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex hardware solutions with signal processing approaches. Instead of using larger physical arrays to achieve better resolution, the system uses phase error correction algorithms and holographic navigation techniques to achieve high measurement precision with compact sensor configurations
Solution Approach 2:
The patent demonstrates that changing operational parameters (frequency, aperture configuration) can achieve different performance levels without fundamentally changing the system architecture, thereby managing complexity while maintaining precision
3Length of stationary object
If low-frequency SAS systems are used to extend navigation range, then range is improved, but angular resolution deteriorates
Solution Approach 1:
The patent implements phase error correction that uses feedback from the received sonar signals to compensate for spatially varying phase errors. This feedback mechanism allows low-frequency systems to maintain angular resolution by actively correcting phase distortions that would otherwise degrade image quality at extended ranges
Solution Approach 2:
The patent applies preliminary phase error correction processing to the sonar signals before final image reconstruction. By pre-correcting phase errors in the signal processing chain, the system maintains angular resolution performance across extended navigation ranges
4Measurement precision
If phase error correction is applied to improve terrain recognition accuracy, then measurement precision is improved, but processing time increases
Solution Approach 1:
The patent performs phase error correction as a preliminary processing step before terrain recognition and navigation decisions. By pre-correcting phase errors in the signal domain, the system improves subsequent recognition accuracy without requiring iterative corrections during real-time navigation
Solution Approach 2:
The patent replaces computationally intensive iterative optimization methods with efficient phase correction algorithms based on holographic navigation principles. This substitution reduces processing time while maintaining high terrain recognition accuracy
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 enhances navigation precision and range, allowing for high-precision positioning and terrain recognition even in challenging ocean conditions, while reducing power consumption and hardware size, making it suitable for smaller autonomous underwater vehicles (AUVs) and unmanned aerial vehicles (UAVs).
Implementation Method 1
synthetic aperture sonar systems for generating images of the terrain
Implementation Method 2
utilize phase error correction and holographic navigation techniques to improve image generation and navigation capabilities, enabling coherent terrain recognition and navigation by compensating for spatially varying phase errors
Data Source
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AI summary
The systems and methods described herein relate to systems and methods for synthetic aperture sonar (SAS) or radar including a pressure compensated fuse for a sensor, holographic navigation, the use of orthogonal signals with SAS, overpinging with multiple SAS transmitters, simultaneous localization and mapping (SLAM) for holographic navigation, high-coverage SAS using orthogonal signals, bistatic gapfilling, and high-frequency holographic navigation using, e.g., grazing angle compensations.