Ladar Underwater Object Detection Using Pseudo-Random Coding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current sonar devices face limitations in detecting objects under water surfaces due to non-stationary propagation scenarios and limited frequency bandwidth, making it difficult to detect small objects or those at long ranges.
Innovation Solution
A laser detection and ranging (ladar) device is used to modulate a laser beam, transmit it towards the water surface, and detect the reflected beam to precisely locate objects underwater, employing binary pseudo-random coding sequences and a processor for high-resolution object detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sonar devices are used to detect objects under water surface, then detection capability is provided, but detection precision and resolution are limited due to non-stationary propagation scenario and limited frequency bandwidth
Solution Approach 1:
The patent replaces the acoustic wave-based sonar system with an optical laser system. Light waves are used instead of acoustic waves to illuminate and detect underwater objects, eliminating the limitations of acoustic wave propagation in water (attenuation, speed variations, reflections). The laser beam provides superior resolution and precision for detecting both surface and submerged objects.
Solution Approach 2:
The patent changes the fundamental wave parameter from acoustic frequency (10 kHz to 1 MHz) to optical frequency. This parameter change enables detection at much longer ranges and with higher precision, as optical waves experience less attenuation and can provide finer resolution details of underwater objects.
2Measurement precision
If acoustic waves are transmitted towards underwater objects, then objects can be detected, but detection range is limited for small objects or long distances due to attenuation and propagation speed variations
Solution Approach 1:
The patent substitutes acoustic wave transmission with laser beam transmission. Optical waves travel much farther in water with less attenuation than acoustic waves, enabling detection of small objects at long distances. The laser's directional nature and higher speed also improve range and precision capabilities.
3Manufacturing precision
If conventional sonar frequency bandwidth is used, then detection is possible, but resolution and precision are insufficient for detailed object detection
Solution Approach 1:
The patent changes the operating frequency from acoustic frequencies (10 kHz to 1 MHz) to optical frequencies. This parameter change provides vastly superior resolution capability, as optical waves can resolve much finer details of underwater objects. The laser's coherent light provides the necessary precision for detailed object characterization.
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
Enables precise and high-resolution detection of objects at various ranges, including short, medium, and long distances, overcoming the limitations of traditional sonar devices.
Implementation Method 1
a laser transmitter (101) being configured to modulate a laser beam by a binary pseudo-random coding sequence to obtain a modulated laser beam
Implementation Method 2
The transmitted laser beam can then be refracted at the water surface and can be reflected by the object under the water surface
Implementation Method 3
The transmitted laser beam can then be refracted at the water surface and can be reflected by the object under the water surface
Implementation Method 4
a laser detector (103) for detecting a reflected laser beam, the reflected laser beam forming a reflected version of the transmitted laser beam
Data Source
AI summary
A laser detection and ranging device for detecting an object under a water surface, the laser detection and ranging device having a laser transmitter being configured to modulate a laser beam by a binary pseudo-random coding sequence to obtain a modulated laser beam, and to transmit the modulated laser beam towards the water surface, a laser detector for detecting a reflected laser beam, the reflected laser beam forming a reflected version of the transmitted laser beam, and a processor for detecting the object under the water surface upon the basis of the reflected laser beam.