Patent ID: 6643588
Filing Date: 2003-11-04
Classification: B60K,B60W

Abstract:
A method for estimating a radius of curvature in a road, the method comprising:measuring a range and an azimuth angle between a host vehicle and a plurality of target vehicles; determining one of whether the host vehicle is changing lanes and whether a primary target vehicle in the plurality of target vehicles is changing lanes; calculating a heading angle of the host vehicle, wherein calculating a heading angle (&eegr;) further comprises calculating the heading angle as defined by: VhL&it;â€ƒ&it;x&it;â€ƒ&it;Î±+Î±=-Î·&it;â€ƒ&it;where&it;:&it;â€ƒVh=â€ƒ&it;the&it;â€ƒ&it;host&it;â€ƒ&it;vehicle&it;â€ƒ&it;speed;â€ƒ&it;L=â€ƒ&it;the&it;â€ƒ&it;range&it;â€ƒ&it;between&it;â€ƒ&it;the&it;â€ƒ&it;host&it;â€ƒ&it;vehicle&it;â€ƒ&it;and&it;â€ƒ&it;the&it;â€ƒ&it;target&it;â€ƒ&it;vehicle;Î±=â€ƒ&it;the&it;â€ƒ&it;azimuth&it;â€ƒ&it;angle&it;â€ƒ&it;between&it;â€ƒ&it;the&it;â€ƒ&it;host&it;â€ƒ&it;vehicle&it;â€ƒ&it;and&it;â€ƒ&it;the&it;â€ƒ&it;target&it;â€ƒ&it;vehicle;calculating a corrected azimuth angle by adjusting the measured azimuth angle by the calculated heading angle; selecting a curve that minimizes a mean square error between the selected curve and a plurality of measured locations of the plurality of target vehicles; and determining an equation that describes the curve, wherein the equation is used to determine the radius of curvature of the road ahead of the host vehicle.