Rotating Directional Antenna Scanning for 3D Subsurface Imaging
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Solution Overview
Problem
Current subsurface and infrastructure investigation radar apparatuses are limited by fixed antenna arrays that cannot extend laterally beyond the vehicle, leading to undetected issues like shoulder ballast fouling and obscured radar shadows under rails, and suffer from poor lateral spatial sampling density, resulting in distorted 3D image data.
Innovation Solution
A method and apparatus that utilize a directional antenna mounted to a moving vehicle, rotated through a 360-degree arc to collect radar data, emitting and receiving RF energy while varying angles to form 3D image data, allowing for higher spatial sampling density and comprehensive subsurface imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a fixed antenna array is used that cannot extend laterally beyond the vehicle, then the device complexity is reduced, but the area of investigation is limited to the subsurface directly under the vehicle
Solution Approach 1:
The patent applies the dynamics principle by transforming the fixed antenna array into a rotating directional antenna system. The antenna rotates about a vertical axis while the vehicle moves forward, dynamically expanding the investigation area from a fixed footprint to a sweeping helical pattern that covers a much larger lateral area without requiring multiple simultaneous antennas.
Solution Approach 2:
The patent introduces a new dimension of rotation about the vertical axis, converting a one-dimensional linear antenna array into a two-dimensional scanning system. This dimensional change allows the single antenna to access multiple lateral positions by rotating, thereby expanding the investigation area without proportionally increasing device complexity.
2Ease of operation
If antennas are vertically fixed with boresight aligned to vertical axis, then the ease of operation is improved, but the measurement precision of lateral subsurface features deteriorates
Solution Approach 1:
The system maintains ease of operation by automating the antenna orientation through rotation about the vertical axis. The dynamic rotation allows the antenna to systematically sweep through different angular positions, achieving precise lateral measurement coverage without requiring manual adjustment or complex multi-antenna geometries.
Solution Approach 2:
The system incorporates feedback mechanisms to track the angular position of the rotating antenna and correlate it with the vehicle's translational position. This feedback enables precise mapping of radar reflections to their corresponding spatial locations, maintaining measurement precision despite the dynamic scanning motion.
3Device complexity
If only three antennas are used in the array, then the device complexity is reduced, but the lateral spatial sampling density deteriorates
Solution Approach 1:
The rotating antenna system dynamically generates high lateral spatial sampling density by continuously sweeping through multiple angular positions. Instead of requiring multiple simultaneously positioned antennas, the single rotating antenna visits each lateral sampling point in sequence, achieving fine sampling density without the complexity of a large antenna array.
Solution Approach 2:
The system employs periodic rotation of the antenna to systematically sample lateral positions. By rotating through a full 360 degrees or appropriate angular range, the antenna periodically revisits sampling points, enabling dense lateral sampling through time-sequential measurement rather than spatial multiplicity.
4Object-affected harmful factors
If the antenna array is positioned between the rails, then the object-generated harmful factors (radar shadow and ring down effect) are reduced, but the area of investigation under the rails deteriorates
Solution Approach 1:
The rotating antenna system dynamically adjusts its illumination pattern by sweeping through different angular positions. This allows the antenna to illuminate areas under the rails from oblique angles during parts of its rotation, compensating for the radar shadow effect that occurs when viewing from directly between the rails, thereby expanding coverage to include previously inaccessible regions.
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 the creation of accurate 3D image data of infrastructure surrounding the vehicle, detecting previously undetected issues and improving lateral sampling density, facilitating targeted maintenance and comprehensive subsurface evaluation.
Implementation Method 1
The directional antenna emits an RF waveform consisting of sets of short-period ultra-wideband (UWB) pulses
Implementation Method 2
receives reflected RF energy
Implementation Method 3
rotating a directional antenna, mounted to the moving vehicle, about an antenna rotation axis with a plane perpendicular to the antenna rotation axis at least partially facing in a direction of movement of the vehicle
Data Source
Figure 1
Figure 2
Figure 3(a)~3(d)
AI summary
A method for forming 3D image data representative of the subsurface of infrastructure located in the vicinity of a moving vehicle. The method includes: rotating a directional antenna, mounted to the moving vehicle, about an antenna rotation axis; performing, using the directional antenna whilst it is rotated about the antenna rotation axis, a plurality of collection cycles in which the directional antenna emits RF energy and receives reflected RF energy; collecting, during each of the plurality of collection cycles performed by the directional antenna: (i) radar data representative of reflected RF energy received by the directional anteuna during the collection cycle; (ii) angular position data representative of an angular position of the directional antenna about the antenna rotation axis during the collection cycle; and (iii) translat ional position data regarding a translational position of the directional antenna during the collection cycle; processing the radar data, the angular position data and the translational position data collected during each of the plurality of collection cycles to form 3D image data representative of the subsurface of infrastructure located in the vicinity of the moving vehicle.