Laser Scanning Vehicle Train for High-Accuracy Digital Terrain Models
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Solution Overview
Problem
Current methods for creating digital terrain models (DTMs) of constructional parts like roads and surfaces lack the necessary elevation accuracy and point density, leading to subjective measurement errors and inefficiencies in construction evaluation and repair navigation.
Innovation Solution
A method utilizing a set of three road vehicles equipped with a laser scanner, GNSS devices, and levelling instruments to create DTM with guaranteed elevation accuracy of 2 mm to 5 mm, minimizing operator subjectivity and atmospheric effects, and enabling objective evaluation and navigation for construction quality assessment and repair processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If contact measuring instruments (total stations, GNSS) are used for terrain surveying, then measurement coverage is improved, but point density and elevation accuracy deteriorate (cannot achieve 25 points/m² or 2-5 mm elevation standard deviation)
Solution Approach 1:
The patent replaces contact-based mechanical measuring instruments (total stations, GNSS receivers requiring physical contact or line-of-sight) with a contactless laser scanning system. The laser scanner emits laser beams that automatically measure distances to all visible points on the terrain surface without requiring operator contact or stabilization of measuring points, thereby achieving both high measurement coverage and high point density (25 points/m²) with improved elevation accuracy (2-5 mm standard deviation).
Solution Approach 2:
The laser scanning system performs automatic measurement of all terrain points within its field of view without requiring operator selection or stabilization of individual points. The system independently captures, processes, and records elevation data from the entire measured area, eliminating the need for manual point-by-point measurement and stabilization that characterizes traditional contact methods.
2Measurement precision
If accurate levelling method is used in combination with total stations or GNSS, then elevation accuracy is improved (1 mm), but measurement time and operational complexity deteriorate (time consuming, requires stabilization, traffic limitation)
Solution Approach 1:
The patent replaces the mechanical levelling process (requiring levelling instruments, stabilization of measuring points, and sequential measurement) with a contactless laser scanning system that simultaneously captures elevation data from all points in the measurement field. This substitution eliminates the need for stabilization of measuring points and reduces measurement time while maintaining high elevation accuracy through the laser's precise distance measurement capability combined with atmospheric compensation.
Solution Approach 2:
The laser scanning system continuously measures all terrain points within its field of view simultaneously, rather than measuring points sequentially as required by the levelling method. This continuous measurement process eliminates interruptions for stabilization and repositioning, thereby significantly improving measurement speed and productivity while maintaining high elevation accuracy through real-time data capture.
3Productivity
If laser scanning in motion is used, then measurement speed is improved, but elevation accuracy deteriorates (cannot achieve 2-5 mm standard deviation)
Solution Approach 1:
The patent introduces an intermediary atmospheric compensation system that corrects for atmospheric effects (temperature, pressure, humidity) on laser beam propagation. This intermediary layer between the laser scanner and the terrain surface compensates for atmospheric disturbances that would otherwise degrade measurement accuracy during motion, enabling the system to maintain 2-5 mm elevation standard deviation even when moving during measurement.
Solution Approach 2:
The system incorporates feedback mechanisms that continuously monitor atmospheric conditions and adjust measurements in real-time. By measuring atmospheric parameters (temperature, pressure, humidity) and using this feedback to correct laser distance measurements, the system compensates for atmospheric effects on the speed of light, thereby maintaining high elevation accuracy during motion-based laser scanning.
4Measurement precision
If static laser scanning with scan-position registration is used, then elevation accuracy is improved, but measurement time and organizational complexity deteriorate (time consuming, requires method combination, traffic limitation)
Solution Approach 1:
The patent integrates multiple measurement functions into a single laser scanning system that simultaneously performs distance measurement, elevation determination, and point cloud generation. This multi-functional approach eliminates the need to combine multiple separate measurement methods (levelling, total station, GNSS) that characterize traditional scan-position registration, thereby reducing organizational complexity and measurement time while maintaining high elevation accuracy through the scanner's integrated capabilities.
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 provides accurate, objective, and repeatable DTM creation with improved elevation accuracy, facilitating precise construction evaluation and navigation, reducing errors and costs in road repairs and quality assessments.
Implementation Method 1
The laser scanner is an active sensor which emits laser beams
Implementation Method 2
The position of the measurement trajectory is determined by the GNSS receiver
Data Source
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AI summary
PROBLEM: Efficiently generating digital terrain model (DTM) having high elevation surface accuracy and high point density, and suitable for controlling pavement milling machines during road repairs. SOLUTION: Combination of motorized levelling and Stop-Go mobile laser scanning system, including train of three vehicles, which are at standstill during measurements, and which move in unison in between measurements. Middle vehicle carries laser scanner, elevation sight, and GNSS receiver. Front and rear vehicle each carry levelling rod; front vehicle also carries GNSS receiver. During measurement cycle, laser scanner generates point cloud, while GNSS positions of middle and front vehicles and elevations at the resp. positions of front and rear vehicles are determined. After measurement cycle, vehicle train moves until rear vehicle halts at previous GNSS position of front vehicle, etc. When all measurement cycles are completed, collected data is integrated and transformed into a DTM.