Method and system for segmentally limiting speed of vehicle

A system for segmentally limiting speed of vehicle, applied for measuring speed of vehicles in real time, comprising:

• an expanded rectangle calculating module configured for receiving characteristic parameters of a route sent by a vehicle monitoring platform, and expanding a plurality of road segments of the route into a plurality of rectangles respectively according to the characteristic parameters of the route;
• a hash table establishing module configured for dividing the plurality of rectangles into blocks sequentially, wherein each block comprises at least two rectangles, and calculating a minimum enclosing rectangle of the at least two rectangles, and establishing a hash table, wherein the hash table comprises vertex information of the minimum enclosing rectangle of each block;
• a current road segment calculating module configured for obtaining an instant longitude and latitude of a moving vehicle, searching in the hash table according to the instant longitude and latitude so as to determine a block where the vehicle is currently located, and determining a road segment where the vehicle is currently located;
• and
• an excessive speed judging module configured for comparing a current speed of the vehicle with a limiting speed of the road segment where the vehicle is currently located, judging whether the vehicle exceeds the limiting speed, and uploading excessive speed information and the instant longitude and latitude of the vehicle to the vehicle monitoring platform if the vehicle exceeds the speed limit;
• wherein the current road segment calculating module comprises:
• a coordinate system establishing unit configured for using the instant longitude and latitude as an origin of coordinate and establishing a rectangular coordinate system, and calculating a quadrant where each of vertexes in each rectangle is located respectively, wherein the rectangle is in the block where the vehicle is currently located;
• an arc algebraic sum calculating unit configured for selecting a rectangle from the block where the vehicle is currently located, accessing each of the vertexes of the rectangle according to a neighbor sequence, recording quadrant changes in each group of adjacent vertexes in the rectangle, obtaining an arc length change of each group of adjacent vertexes by searching in the hash table according to the quadrant changes, and calculating an arc length algebraic sum corresponding to the rectangle according to the arc length change in each group of adjacent vertexes;
• and
• a judging unit configured for determining a positional relationship between the instant longitude and latitude of the vehicle and the rectangle according to the arc length algebraic sum.