Badge Reader Position Calibration Using Vehicle Speed and Time
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Solution Overview
Problem
The existing methods for calibrating the position of a badge reader on a gantry overhanging a traffic lane require interrupting traffic and using static visual cues, making them inefficient and prone to disruption by external events, which can degrade the reception quality of the badge reader.
Innovation Solution
A method that calculates the distance of the badge reader from the traffic lane by estimating the average speed of vehicles and time difference of their passage using lasers, allowing for continuous calibration without interrupting traffic or using static visual cues, and updates this estimate with each passing vehicle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If static visual cues (center lines, roadside lines, poles) are used for calibration, then the badge reader position can be determined, but traffic must be interrupted and the process becomes complex
Solution Approach 1:
The system uses the vehicles themselves as calibration references by detecting their badges and measuring their speeds and positions. The moving vehicles provide the calibration data needed, eliminating the requirement for external static visual cues and traffic interruption.
Solution Approach 2:
The patent replaces the mechanical/static calibration system (visual cues, physical markers) with a dynamic electronic system that uses RFID badge detection, laser speed measurement, and computational algorithms to determine badge reader positioning continuously.
2Measurement precision
If static visual cues are installed on the traffic lane, then calibration can be performed, but the device complexity increases and external events can still affect positioning
Solution Approach 1:
The calibration system uses the vehicles' own badges as references, eliminating the need for external static visual cues. The vehicles themselves provide the measurement baseline through their badge signals, speed, and position data.
Solution Approach 2:
The patent extracts the calibration function from external static infrastructure and relocates it to the moving vehicles themselves. By using vehicle badges as the reference frame, the system removes the complexity of installing and maintaining static visual cues.
3Ease of manufacture
If the badge reader position is fixed, then installation is simple, but external events (wind, bird impacts) can degrade reception quality
Solution Approach 1:
The system continuously monitors beacon reception quality and calculates real-time positioning errors based on vehicle speed and position measurements. This feedback enables dynamic compensation for position drift caused by external events, maintaining reliable reception without complex physical stabilization.
Solution Approach 2:
The patent transforms the static badge reader positioning problem into a dynamic solution by continuously measuring and compensating for position changes. The system adapts to external disturbances by using real-time vehicle data to calculate and correct positioning errors.
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 method provides precise and continuous calibration of the badge reader's position, ensuring optimal reception quality and minimizing the impact of external events, with an estimated precision of 10 cm accuracy after 100 vehicle passes.
Implementation Method 1
calculation of an estimate of said distance by the ratio between a measured average speed of the vehicle and the time difference between a moment of detection of the badge of a vehicle by said badge reader, and a moment of passage of the vehicle at the verticality of the gantry
Implementation Method 2
A badge B emits a beacon in the form of short distance waves of the RFID (Radio Frequency Identification in English) or even DSRC (Dedicated Short Range Communications in English) type. The beacon is received by the badge reader 2
Data Source
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AI summary
The invention relates to a method and a device for calibrating the position of a badge reader (2) on board a vehicle, said badge reader (2) being mounted on a portal frame overhanging a travel lane in such a way that it points towards a point on the travel lane located at a predetermined distance (D) from the vertical of the portal frame. The method is characterised in that it comprises the following steps: calculation of an estimate (formula I) of said distance (D) by working out the ratio between a measured average speed (VMi) of the vehicle (Vi) and the time distance between the moment ( ti 1) of detection of the badge of a vehicle (Vi) by said badge reader and the moment of the passage ( ti 2 ) of the vehicle (Vi) directly below the portal frame; and calculation of an average estimate (formula II) of said distance (D) by working out the average of a plurality of thus calculated estimates (formula I) of said distance (D) following the passage of a plurality of vehicles beneath the portal frame.