Lane monitoring with electronic horizon

A method of detecting a lane position of a vehicle on a roadway, comprising the steps of:

• maintaining a first lane model based on optical sensor data, wherein the first lane model includes a lane heading and a lane marker offset distance;
• maintaining a second lane model based on monitored vehicle position and a map database, wherein the second lane model includes a pathline heading and a virtual offset distance;
• obtaining a pathline representing the roadway from the map database;
• determining a point on the pathline closest to the vehicle;
• determining the pathline heading in response to a direction of the pathline at the closest point;
• determining a lateral offset distance between the vehicle and the closest point;
• determining the virtual offset distance by shifting the pathline according to a difference between the lateral offset distance of the pathline and the lane marker offset distance of the first lane model;
• evaluating a similarity of the models;
• and
• selecting an active lane model in response to whether lane markers are being detected in the optical sensor data and whether the similarity is above a predetermined similarity.

Apparatus for a vehicle operated on a roadway having lane markers, comprising:

• an optical sensor providing optical data of the roadway;
• a first lane model stored in an electronic memory in response to detected lane markers in the optical data;
• an electronic horizon system tracking a position of the vehicle and providing roadway data in response to the position;
• a second lane model stored in the electronic memory in response to the roadway data;
• a confidence checker comparing a discrepancy between the first and second lane models to a threshold in order to determine a confidence level;
• and
• an output selector that selects the first lane model when lane markers are detected in the optical data, and that selects the second lane model if the lane markers are not detected in the optical data and the confidence level is greater than a predetermined level;
• wherein the first lane model includes an optical heading (φLane), wherein the second lane model includes an electronic horizon heading (φEH), and wherein the discrepancy compared by the confidence checker to the threshold is comprised of an absolute value of a difference φEH−φLane.

Apparatus for a vehicle operated on a roadway having lane markers, comprising:

• an optical sensor providing optical data of the roadway;
• a first lane model stored in an electronic memory in response to detected lane markers in the optical data;
• an electronic horizon system tracking a position of the vehicle and providing roadway data in response to the position;
• a second lane model stored in the electronic memory in response to the roadway data;
• a confidence checker comparing a discrepancy between the first and second lane models to a threshold in order to determine a confidence level;
• and
• an output selector that selects the first lane model when lane markers are detected in the optical data, and that selects the second lane model if the lane markers are not detected in the optical data and the confidence level is greater than a predetermined level;
• wherein the first lane model includes an optical vehicle to lane offset distance (dLane), wherein the second lane model includes an electronic horizon vehicle to pathline offset distance (dEH), and wherein the discrepancy compared by the confidence checker to the threshold is comprised of a variance of dEH−dLane.