Vehicle Speed Estimation via Street Light Intensity
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Solution Overview
Problem
Existing positioning systems for vehicles, particularly those using GNSS signals, face accuracy limitations when GNSS signal reception is poor or unavailable, such as in tunnels, relying heavily on inertial sensors which can introduce considerable errors, especially in mobile devices like smartphones.
Innovation Solution
A method that utilizes the variation in intensity of light emitted from light sources positioned along a road segment to estimate the velocity of a vehicle, independent of GNSS signals, by detecting light intensity using a mobile device's camera or light sensor and calculating velocity based on the periodic variation of light intensity and the mutual distance between light sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inertial sensors are used to estimate vehicle trajectory when GNSS signal is unavailable, then positioning can continue in tunnels, but measurement precision deteriorates due to sensor limits causing considerable errors
Solution Approach 1:
The patent replaces the mechanical inertial sensing system with an optical measurement system. Instead of using accelerometers and gyroscopes to estimate trajectory, the system uses a light sensor to detect variations in light intensity from street lamps, thereby determining vehicle speed and position without relying on mechanical sensors that accumulate errors.
Solution Approach 2:
The patent introduces light intensity variations from street lamps as an intermediary medium for measurement. The light sensor detects these variations, which serve as a reference signal to calculate vehicle speed and position, replacing the direct mechanical measurement approach with an indirect optical reference-based method.
2Measurement precision
If GNSS-based positioning is used, then positioning accuracy is maintained, but positioning fails when GNSS signal reception is poor or unavailable
Solution Approach 1:
The patent introduces light intensity variations from street lamps as an intermediary measurement reference. By detecting these periodic variations with a light sensor, the system can determine vehicle speed and position independently of GNSS signals, providing an alternative measurement pathway that works in signal-denied environments.
Solution Approach 2:
The patent changes the measurement parameter from GNSS signal reception to light intensity detection. Instead of relying on satellite signals, the system measures the intensity of light from street lamps over time, using the temporal variations in light intensity to infer vehicle motion parameters such as speed and position.
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 enables accurate navigation and velocity estimation even in areas with poor or no GNSS signal reception, reducing reliance on inertial sensors and improving positioning accuracy without requiring specific modulating or demodulating of visible light signals.
Implementation Method 1
detecting light intensity using a mobile device's camera or light sensor and calculating velocity based on the periodic variation of light intensity
Data Source
AI summary
A method is provided that is performed by at least one first apparatus with the method including obtaining or causing obtaining information indicative of a variation in intensity of light emitted from at least two light sources positioned along a segment of a road; and obtaining or causing obtaining information indicative of a velocity of the at least one first apparatus based at least on the information indicative of the variation in intensity. A corresponding apparatus is also provided.