Intelligent vehicle highway system sensor and method

A sensor for detecting the presence of an object within an area, the sensor comprising:

• means for emitting a first output of pulsed, coherent radiation in a forward plane toward a first fixed area a known distance from the emitting means;
• means for scanning the first output radiation across the first fixed area;
• means for receiving a portion of the returning first pulsed energy reflected from the first area;
• means for determining a time of flight change for pulses between the first emitting and first receiving means caused by the presence of an object in the first area;
• means for emitting a second output of pulsed, coherent radiation in a backward plane toward a second fixed area a known distance from the emitting means;
• means for scanning the second output radiation across the second fixed area;
• means for receiving a portion of the returning second pulsed energy reflected from the second area;
• means for diverting the pulsed energy output of the emitting means into two diverging directional beams;
• means for determining a time of flight change for pulses between the second emitting and second receiving means caused by the presence of an object in the second area;
• and
• means for receiving input from the time of flight determining means and for providing range, angle and speed output for indicating whether the object meets one of a plurality of classification criteria.

A sensor for detecting the presence of a vehicle within close range and suitable for measuring traffic speed and vehicle classification, the sensor comprising:

• means for emitting a directional output of pulsed energy toward a fixed area a known distance from the emitting means;
• means for scanning the pulsed energy output in a fixed plane;
• means for receiving a portion of returning pulsed energy reflected from the area;
• means for determining a time-of-flight change for pulses between the emitting and receiving means caused by the presence of a vehicle in the area;
• means for determining a vehicle speed as the vehicle passes through the fixed area;
• means for processing signals received from the emitting, scanning, receiving and speed determining means for providing range and sensor angle data, the data useful in determining a vehicle profile;
• and
• means for comparing the vehicle profile with predetermined profiles for classifying the vehicle.

A method for determining the shape of a vehicle useful in classify the vehicle, the method comprising the steps of:

• providing a sensor having a laser beam transmitter and optical receiver for the beam;
• determining a range from the sensor to a vehicle when the vehicle travels within a sensing zone of the sensor;
• providing respective range data outputs corresponding with a sensor angle for a range to a point on the vehicle;
• scanning the laser beam across the vehicle for determining the range for points on two dimensions of the vehicle;
• determining the beam orientation and a corresponding sensor angle;
• determining a vehicle speed;
• and
• processing the ranges and corresponding angles for providing a multiplicity of two dimensional cross-sectional profiles of the vehicle;
• positioning the profiles based on the vehicle speed;
• and
• providing a three dimensional image representative of the vehicle, the image useful in classifying the vehicle.

A method for determining the shape of a vehicle for purposes of classification of the vehicle, the method comprising the steps of:

• providing a sensor having a laser beam transmitter and an optical receiver for the laser beam;
• scanning the laser beam across the vehicle in a predetermined scanning zone;
• measuring a range and angle for a plurality of scanned cycles as the vehicle travels through the zone;
• measuring a time and distance traveled by the vehicle within the zone;
• and
• processing the measured range, angle, travel time and distance data for determining a vehicle profile and speed.