DETECTING LOCATION, TIMETABLE AND TRAVEL TIME ESTIMATIONS FOR BARRIER CROSSINGS IN A DIGITAL MAP
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Abstract
A method for determining barrier crossing information for convoyed objects (22) using historic trajectory data (28). Trajectories (28) having similar geographical and directional properties are bundled so that trajectory density can be measured as a function of position and time (s, t). Visual presentation of the trajectory information can be used to determine certain types of barrier crossing information useful in a digital map. Frequency analysis on a number of trajectory density time series may be performed to determine specific barrier crossing locations (26) through the detection of vehicle bursts. Such frequency analysis may also indicate barrier crossing times and schedules in the case of crossing patterns.
26 Citations
20 Claims
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1-19. -19. (canceled)
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20. A method for determining barrier crossing information using historic trajectory data, said method comprising the steps of:
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receiving trajectory data representative of the movements of a plurality of objects over a network of travel paths with respect to time, said trajectory data for an object comprising a plurality of sequential time-stamped geo-positions, and said network of travel paths comprising at least one barrier crossing which periodically impedes or restricts the free flow of objects along the network of travel paths; associating the received trajectory data with segments of a digital map, said segments being representative of the network of travel paths; determining the trajectory density along at least some of the segments as a function of position and time from the trajectory data, the trajectory density being indicative of the number of objects at a particular location and time; identifying locations at which the trajectory density changes periodically from zero to substantially greater than zero; using said identified locations to determine the location of a barrier crossing and augmenting the digital map with the determined location of the barrier crossing, the barrier crossing being between a first segment and a second segment; determining a crossing timetable and/or crossing frequency for the barrier crossing from the changes in trajectory density; and associating the determined crossing timetable and/or crossing frequency with the barrier crossing in the digital map.
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Specification