Vehicle Stop Determination Using Velocity Transition Models
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Solution Overview
Problem
Existing GPS-based methods for determining whether a vehicle has stopped face challenges in accuracy due to low velocity measurements, leading to false determinations, as changes in velocity direction can be influenced by environmental factors like reflected radio waves, rather than the vehicle's movement.
Innovation Solution
A vehicle-stop determination method and system that extract a low-velocity section from GPS data, generating a vehicle velocity transition model using section distance and time, and determining a stop based on the presence of a velocity zero or lower section within this model, ensuring accurate stop detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a threshold value higher than zero is used to determine vehicle stop, then the security of stop determination is improved, but the accuracy of velocity measurement is degraded
Solution Approach 1:
The patent changes the determination parameter from velocity alone to a composite parameter combining velocity and direction change. This allows using a higher velocity threshold while compensating for reduced measurement accuracy by adding directional information as a discriminating factor.
Solution Approach 2:
The patent introduces a new dimension (direction of velocity vector) to the determination process. By considering both magnitude (velocity) and direction changes, the system can use higher velocity thresholds without sacrificing accuracy, as false stops would not exhibit the characteristic large direction changes.
2Measurement precision
If a lower threshold value is used to prevent false determination, then the accuracy of velocity measurement is improved, but the possibility of false stop determination increases
Solution Approach 1:
The patent changes from single-parameter (velocity) determination to two-parameter determination (velocity + direction change). This allows using lower velocity thresholds to capture more potential stops while filtering out false positives through the direction change criterion.
Solution Approach 2:
The system uses direction change information as feedback to validate velocity-based stop determinations. When velocity suggests a stop but direction change is minimal, the system can reject the false positive, effectively using one measurement to correct another.
3Reliability
If the direction of velocity vector is used to determine vehicle stop, then the possibility of false stop determination is reduced, but the measurement accuracy is degraded due to environmental factors
Solution Approach 1:
The patent performs preliminary filtering by checking velocity threshold before analyzing direction changes. This preliminary action reduces the number of cases where directional measurement errors would lead to false determinations, as only low-velocity cases are subjected to direction analysis.
Solution Approach 2:
The patent applies direction change analysis selectively only to cases where velocity is below the threshold. This local application of the directional criterion avoids the pitfalls of using directional measurements in high-velocity scenarios where environmental interference is more significant.
Data Source
AI summary
Device (100) has: a low-speed interval extraction unit (120) for extracting, from GPS information, a low-speed interval extending from the location at a first time point at which the measured speed of a vehicle has fallen below a prescribed value, to the location at a second time point at which the speed has exceeded the prescribed value; a vehicle speed transition model generating unit (130) for generating a model having, as constraint condition, the length and the amount of time of the low-speed interval, for indicating temporal transition of the speed in such a way that the speed continuously increases to the second time point after having decreased from the first time point; and a stop determination unit (140) for determining that the vehicle has stopped within the low-speed interval, on the condition that an interval in which the speed is zero or less is present within the model.