Collision detection system and method of estimating target crossing location
A collision detection system and method of estimating a crossing location are provided. The system includes a first sensor for sensing an object in a field of view and sensing a first range defined as the distance between the object and the first sensor. The system also includes a second sensor for sensing the object in the field of view and sensing a second range defined by the distance between the object and the second sensor. The system further includes a controller for processing the first and second range measurements and estimating a crossing location of the object as a function of the first and second range measurements. The crossing location is estimated using range and range rate in a W-plane in one embodiment and using a time domain approach in another embodiment.
1. A method of estimating a crossing location of an object, said method comprising the steps of:
sensing the presence of an object in a field of view;
tracking the object with first and second sensors;
measuring range to the object with the first sensor;
measuring range to the object with the second sensor, wherein the first and second sensors are separate from each other;
determining a first range rate of the object with the first sensor, and determining a second range rate of the object with the second sensor;
computing a mathematical square of range and a mathematical square of the product of range and range rate for each of the plurality of measurements taken with the first sensor and generating a first curve as a function thereof;
computing a mathematical square of range and a mathematical square of the product of range and range rate for each of the plurality of measurements taken by the second sensor and generating a second curve as a function thereof; and
estimating the crossing location of the object as a function of the first and second curves.
2. The method as defined in claim 1 , wherein the crossing location is estimated relative to a location midway between the first and second sensors.
3. The method as defined in claim 1 , wherein the step of estimating the crossing location of the object as a function of the first and second curves comprises computing the distance between the first and second curves and dividing the distance by twice the separation distance of the first and second sensors to estimate the crossing location relative to a location midway between the first and second sensors.
4. The method as defined in claim 1 , wherein the method estimates the crossing location of the object relative to a vehicle.
5. The method as defined in claim 4 , further comprising the step of
generating a collision output signal as a function of the estimated crossing location.