MPiA Laser Scanning with Range Probing for Pulse Ambiguity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing multiple-pulses-in-air (MPiA) laser scanning systems face challenges in accurately assigning return pulses to their corresponding send pulses due to high pulse repetition frequencies, leading to ambiguity and computational complexity, especially in environments with rapidly changing elevations.
Innovation Solution
A laser scanning system that employs range probing at intermittent points in time, using range tracking to assign return pulses to send pulses based on measurement values from neighboring pulses, and incorporates heuristic techniques to minimize computational complexity and error, generating a 3D point cloud with confidence-based corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pulse repetition frequency is increased to accelerate data acquisition, then productivity is improved, but measurement precision deteriorates due to the multiple-pulses-in-air problem and ambiguity in pulse assignment
Solution Approach 1:
The system performs preliminary range probing at intermittent points in time to establish reference measurement values before the main scanning. These probe values are used to predict expected range values, which are then incorporated into the pulse assignment process to resolve ambiguities caused by high pulse repetition frequencies.
Solution Approach 2:
The system uses a feedback mechanism where previously determined measurement values from neighboring pulses are taken into account when assigning return pulses to send pulses. This contextual information from adjacent pulses helps disambiguate return pulses in high PRF conditions, maintaining measurement precision while enabling higher productivity.
2Loss of time
If the pulse repetition frequency is increased to reduce measurement time, then loss of time is reduced, but device complexity increases due to the need for sophisticated ambiguity resolution algorithms
Solution Approach 1:
Instead of performing full ambiguity resolution for every pulse, the system uses a hybrid approach: range probing is performed only at intermittent points rather than continuously, and measurement values from only neighboring pulses are considered. This partial application of complexity-reducing techniques maintains sufficient accuracy while significantly reducing computational burden.
Solution Approach 2:
Range probing is performed in advance at intermittent points to establish reference values that simplify subsequent pulse assignment. By having these preliminary reference measurements available, the system reduces the computational complexity required for real-time ambiguity resolution during main scanning operations.
3Measurement precision
If range probing is performed continuously to improve pulse assignment accuracy, then measurement precision is improved, but productivity decreases due to increased computational load and measurement time
Solution Approach 1:
The system performs range probing only at intermittent points in time rather than continuously, which is sufficient to maintain measurement precision while significantly improving productivity. The probe values obtained at these intermittent points are then used in conjunction with neighboring pulse information to resolve ambiguities for all pulses.
Solution Approach 2:
Range probing is performed at selective intermittent points to establish reference measurement values that can be used to inform pulse assignment for subsequent pulses. This preliminary action at key moments provides sufficient information to maintain accuracy without requiring continuous probing that would reduce productivity.
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
The system provides efficient and robust MPiA laser scanning by reducing computational complexity and error rates, ensuring accurate distance measurements and improved 3D point cloud generation even in complex terrains.
Implementation Method 1
measuring the time-of-flight of laser pulses of a laser scanner... the distance to the target is determined on the basis of the time of flight of the pulses
Implementation Method 2
emitting pulsed electromagnetic radiation onto a target to be surveyed and subsequently receiving the radiation that is returned by the target
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a multiple-pulses-in-air (MPiA) laser scanning system, wherein the MPiA problem is addressed in that an MPiA assignment of return pulses to send pulses of a laser scanner is based on range tracking and range probing at intermittent points in time, wherein each range probing comprises a time-of-flight arrangement which is constructed to be free of the MPiA problem. The invention further relates to an MPiA laser scanning system, wherein an MPiA ambiguity within a time series of return pulses, is converted into 3D point cloud space, which provides additional information from the spatial neighborhood of the points in question to enable MPiA disambiguation.