Inter-vehicle Distance Estimation Using Observable Vehicle Speeds
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Solution Overview
Problem
Existing inter-vehicle distance estimation methods, such as those using target tracking devices, face accuracy issues when vehicles change speed, particularly in lines of vehicles where the speed of the tracking target is used, leading to decreased accuracy in estimating inter-vehicle distances.
Innovation Solution
An inter-vehicle distance estimation method and device that employs a sensor system including a ranging sensor, image sensor, or radar to detect positional and speed information of surrounding vehicles, combined with map data and movement information, to estimate inter-vehicle distances based on the speeds of observable and unobservable vehicles in the same traffic lane, using the speeds of observable vehicles to estimate the speeds of unobservable vehicles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the speed of the tracking target at the point when the tracking target was screened is used as its speed, then the estimation process is simplified, but the accuracy of inter-vehicle distance estimation decreases when the tracking target changes speed
Solution Approach 1:
The patent introduces an intermediary vehicle (a vehicle whose speed can be observed) as a mediator to estimate the speed of the tracked vehicle. Instead of directly using the tracked vehicle's speed which becomes unreliable when screened, the system uses the speed of another vehicle in the same lane as an intermediate reference to infer the tracked vehicle's speed, thereby maintaining accuracy without significantly complicating the system.
Solution Approach 2:
The patent copies the speed information from one vehicle (the intermediary vehicle with observable speed) to estimate the speed of the tracked vehicle. By assuming vehicles in the same lane travel at similar speeds, the system creates a speed profile copy that can be applied to the tracked vehicle even when its direct speed measurement is unavailable or inaccurate.
2Measurement precision
If multiple observable vehicles are used to estimate the speed of unobservable vehicles, then the accuracy of speed estimation improves, but the complexity of data processing increases
Solution Approach 1:
The patent applies partial action by using only the necessary number of observable vehicles (typically two) to estimate the speed of unobservable vehicles, rather than processing data from all possible vehicles. This selective approach provides sufficient accuracy for speed estimation while avoiding the excessive computational complexity that would result from utilizing all available vehicle data.
Data Source
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AI summary
An inter-vehicle distance estimation method according to one aspect of the present invention includes: estimating a screened area screened by an obstacle from a sensor and two unscreened areas sandwiching the screened area; and, based on speeds of two tracked vehicles traveling in a same traffic lane respectively within the two unscreened areas, estimating the inter-vehicle distances from the two tracked vehicles to a tracked vehicle traveling in the same traffic lane within the screened area.