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Trajectory data compression

  • US 10,048,075 B2
  • Filed: 10/16/2013
  • Issued: 08/14/2018
  • Est. Priority Date: 07/19/2013
  • Status: Active Grant
First Claim
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1. A method for more efficiently compressing locational data and for performing real-time analytics of such locational data comprisingproviding raw trajectory data of an object, the raw trajectory data relates to a physical trajectory of the object and is derived from a signal collection system;

  • processing, by a processor, the raw trajectory data to identify key data points from the raw trajectory data, the key data points include primary key data points and secondary key data points, wherein identifying the key data points is based on compression parameters comprisingTmax which is the maximum time constant that when exceeded, indicates that the object is stationary,Dmin which is the minimum distance control parameter to tolerate signal noises and error,Dmax which is the maximum distance for indicating that the object is moving, andθ

    min which is the minimum angle for indicating that the object is turning, the compression parameters are used todetermine if a current data point under analysis Ptc is a primary key data point, wherein a primary key data point comprises begin (B) or end (E) points, andin response to determining that the data point Ptc is not a primary key data point, determine if one or more data points in a temporary buffer (Ptemp) is a secondary key data point, wherein a secondary key data point comprises a turn (T) point which indicates that the object is turning at an angle relative to a previous data point;

    removing, by the processor, data points from the raw trajectory data which are not identified as key data points (non-key data points) thereby reducing an amount of data required to characterize the physical trajectory of the object;

    storing the key data points as a set of compressed trajectory data points P′

    corresponding to a compressed trajectory of the object, the compressed trajectory represented by at least one segment, whereinprimary key data points define ends of the segment, andsecondary key data points are intermediate key data points between ends of the segment; and

    analyzing, by the processor, the compressed data points to provide an analysis for developing traffic models, wherein the analysis comprisesdetermining accuracy and error tolerance of a data compression system by adjusting at least one of input compression parameters.

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