Worker Positioning via Sensor Fusion and GNSS
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Solution Overview
Problem
The existing worker management systems face challenges in accurately monitoring the positions of workers across a construction site due to poor positioning accuracy of Global Navigation Satellite System (GNSS) devices, especially when signals from satellites are obstructed or of low reception quality, affecting the reliability of three-dimensional position calculations.
Innovation Solution
A worker management system comprising a terminal device carried by workers, a worker detection system mounted on work machines, and a site management device connected via a wireless communication network, which uses a combination of GNSS devices and surrounding monitoring sensors to transmit and calculate accurate positional information, including worker identification and work machine status, to provide comprehensive site coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a GNSS device with high reception sensitivity is used, then positioning accuracy is improved, but device size and weight increase
Solution Approach 1:
The system divides positioning functionality into two segments: work machines use high-sensitivity GNSS devices for accurate positioning, while workers use lightweight portable devices with lower sensitivity. The central control unit integrates these different quality levels of positioning data to achieve overall system accuracy without requiring every device to be heavy and expensive.
Solution Approach 2:
Different quality levels of positioning equipment are assigned to different locations and roles on the construction site. Work machines, which are stationary or slowly moving, use high-accuracy GNSS devices. Workers, who need mobility and portability, use lightweight devices with lower sensitivity. This local differentiation optimizes overall system performance while considering specific operational requirements at each location.
2Measurement precision
If a GNSS device with high reception sensitivity is used, then positioning accuracy is improved, but device cost increases
Solution Approach 1:
The system segments positioning equipment costs by application: expensive high-sensitivity GNSS devices are deployed only on work machines where they provide maximum value, while workers use cheaper portable devices. The central control unit reconciles these different data qualities, achieving accurate worker positioning without requiring every worker to carry expensive equipment.
Solution Approach 2:
High-cost positioning equipment is deployed only where most beneficial - on work machines that serve as stable reference points. Lower-cost equipment is used for workers who need mobility and portability. This local quality differentiation optimizes cost-effectiveness while maintaining overall positioning accuracy through centralized data integration.
3Area of stationary object
If GNSS positioning is used in obstructed environments, then worker monitoring coverage is improved, but positioning accuracy deteriorates
Solution Approach 1:
The central control unit acts as an intermediary that receives positioning data from both work machines and workers, processes this information, and resolves accuracy issues. When worker GNSS signals are obstructed, the system uses work machine positions (which have better reception) and sensor data as reference points to calculate accurate worker positions through collaborative positioning algorithms.
Solution Approach 2:
The system merges multiple positioning data sources - GNSS data from work machines, GNSS data from workers, and sensor information - into a unified positioning solution. This combination allows the system to compensate for poor worker GNSS reception in obstructed environments by using the more reliable work machine positioning data and sensor measurements to determine accurate worker positions.
Data Source
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AI summary
In a worker management system comprising a terminal device, a worker detection system, and a site management device, the terminal device transmits a worker signal, which includes terminal GNSS positional information represented by a GNSS coordinate system of the terminal device, to the site management device. The worker detection system transmits worker detected positional information, which indicates a position of the worker detected by a surrounding monitoring sensor mounted on the work machine, to the site management device. The site management device relates the terminal GNSS positional information to the worker detected positional information, and when both information for the same worker is available, it selects a position indicated by the worker detected positional information, and when only the terminal GNSS positional information is available, it selects a position indicated by the terminal GNSS positional information, as a current position of the worker.