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System and method for creating, storing, and updating local dynamic MAP database with safety attribute

  • US 9,435,654 B2
  • Filed: 01/24/2014
  • Issued: 09/06/2016
  • Est. Priority Date: 06/01/2013
  • Status: Active Grant
First Claim
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1. A method for creating, storing, and updating local dynamic map database with safety attribute, for a street or highway, said method comprising:

  • a central computer obtaining basic safety messages in an intended region of map, wherein the basic safety messages include vehicle data;

    filtering out a first basic safety message data out of said basic safety messages which falls outside of said intended region of map;

    adaptively defining said intended region of map, using speed profiles data in each road segment of interest;

    wherein a high average speed road segment requires greater map coverage than a low average speed road segment;

    receiving path history or trajectory from an at least one vehicle;

    checking accuracy of said path history or trajectory;

    when said accuracy of said path history or trajectory is better than a first accuracy threshold distance, storing said path history or trajectory, instead of actual locations reported by said at least one vehicle;

    when said accuracy of said path history or trajectory is worse than said first accuracy threshold distance, storing said actual locations reported by said at least one vehicle;

    storing a location, heading, speed, and timestamp of each of said basic safety messages received; and

    when corresponding number of vehicles for stored data is above a first number of vehicle threshold, then starting generation of a temporary map;

    said central computer further;

    generating lanes, wherein generating lanes includes;

    assigning equal weights for all paths at beginning, as an initialization step;

    combining paths or parts of paths which have a separation distance of smaller than a threshold fraction of a lane width, to produce a resultant path, to indicate that said paths or parts of paths are actually the same;

    wherein weight of said resultant path is calculated using the equation;


    (1/sqrt(((1/w1)2*(1/w2)2)/((1/w1)2+(1/w2)2)))wherein sqrt is the square root function, w1 is weight of a first path, and w2 is weight of a second path;

    combining paths which start and end with same heading angles;

    combining parts of paths of vehicles which have same headings in said parts;

    updating weights of the paths or parts of the paths of combined paths which are headed in same direction, using the equation;


    (1/sqrt(((1/w1)2*(1/w2)2)/((1/w1)2+(1/w2)2)))detecting lane changes in captured data, wherein detecting lane changes includes using statistical median operation to filter outliers in positions and paths for lane change detection;

    determining an intersection region and splitting lanes wherein determining an intersection region and splitting lanes includes;

    identifying an intersection diamond region using speed profiles of vehicles, heading angles of said vehicles, and intersection of lanes, generated from said vehicles'"'"' travel paths;

    obtaining intersection of lanes, generated from said vehicles'"'"' travel paths;

    constructing intersection points of lanes for each of lanes which differ in heading angle by more than a threshold angle value;

    constructing a convex polygon using said intersection points of lanes;

    expanding a convex polygon by adding a certain amount of width, equal to a specific fraction of lane width on each of sides;

    splitting lanes, based on intersection region polygon;

    determining lane type as ingress or egress, wherein determining lane type includes determining a difference in angle between vehicle heading and lane heading;

    combining incoming and outgoing lanes which fall on one side of said polygon and have either same or exactly opposite heading angle, with difference of approximately 180 degrees;

    determining connected lanes;

    determining movement states for each of said ingress lanesbased on connected egress lane'"'"'s maneuver code,wherein connection maneuvers comprise;

    left-turn, straight, or right-turn;

    updating said map data;

    generating lanes for said street or highway.

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