Tunnel Speed Estimation Using Upstream Probe Data
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Solution Overview
Problem
Current navigation systems are unable to accurately determine vehicle speed and traffic conditions within tunnels due to the loss of GPS satellite signals, leading to inaccurate map matching and location determination, and inability to assess real-time traffic congestion.
Innovation Solution
A method and apparatus that aggregate probe data using network geometry topology to estimate tunnel speed by designating probe points upstream and downstream of the tunnel, allowing for the calculation of temporary tunnel speed and congestion status based on timestamp differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS probe data is used to determine vehicle speed and location, then navigation accuracy is improved, but GPS satellite signals are lost in tunnels causing measurement failure
Solution Approach 1:
The patent introduces an intermediary calculation method that uses probe data from upstream and downstream of the tunnel along with network geometry topology to estimate tunnel speed, rather than relying directly on GPS signals within the tunnel. This intermediary approach bridges the gap caused by signal loss.
Solution Approach 2:
The system collects and processes probe data upstream of the tunnel before the vehicle enters, designating it as the starting point with a timestamp. This preliminary data collection enables subsequent speed estimation when GPS signals are unavailable inside the tunnel.
2Loss of information
If real-time traffic congestion assessment is implemented, then traffic information accuracy is improved, but GPS signal loss in tunnels prevents data collection
Solution Approach 1:
The patent uses probe data from locations outside the tunnel (upstream and downstream) as intermediaries to infer traffic conditions within the tunnel. By calculating temporary tunnel speed based on these intermediary points and comparing it with actual speed when available, the system maintains traffic information completeness without requiring direct GPS signals inside the tunnel.
Solution Approach 2:
The system establishes a feedback mechanism where temporary tunnel speed estimates are continuously updated and refined. When probe data becomes available downstream or when vehicles exit the tunnel, the system compares estimated speeds with actual speeds to improve future estimations, ensuring accurate traffic information even during periods of signal loss.
3Measurement precision
If map matching is performed using GPS probe data, then location determination accuracy is improved, but GPS signal loss causes matching failure
Solution Approach 1:
The system performs preliminary designation of probe points upstream of the tunnel as starting points with recorded timestamps before the vehicle enters the tunnel. This preliminary action establishes a reference framework that enables continuous location tracking through the tunnel using network geometry topology even without GPS signals.
Solution Approach 2:
The patent creates a virtual representation of the tunnel path using network geometry topology data, effectively copying the physical tunnel structure into a digital model. This allows map matching to continue using the topological copy rather than relying on GPS signals that are unavailable in the physical tunnel environment.
Data Source
AI summary
An approach is provided for determining tunnel speed for a vehicle travelling through a tunnel. A tunnel processing platform aggregates probe data associated with at least one vehicle into at least one tunnel path based, at least in part, on a network geometry topology for at least one tunnel. The tunnel processing platform also designates at least one probe point collected upstream of the at least one tunnel as at least one starting point of the at least one tunnel path and at least one temporary probe point as at least one endpoint of the at least one tunnel path, wherein the at least one temporary probe point is downstream of the at least one tunnel. It then determines at least one temporary tunnel speed for the at least one tunnel path based, at least in part, on the timestamp for the at least one probe point and the current time associated with the at least one temporary probe point.