Method for determining a time to impact in a danger zone for a vehicle having a pre-crash sensing system

A method for operating a pre-crash sensing system for a source vehicle having a source vehicle width and length having a countermeasure system, said method comprising:

• measuring a source vehicle speed;
• determining an object distance, object relative velocity and object travel direction;
• determining an object classification with a vision system;
• determining an object length and object width corresponding to the object classification;
• determining a danger zone based on the source vehicle length, source vehicle width, object length, object width and object travel direction;
• determining a source vehicle time interval corresponding to the time the source vehicle is within said danger zone;
• determining an object time interval corresponding to the time the object is within said danger zone;
• and
• when the source vehicle time interval coincides with the object time interval, activating the countermeasure system.

A method for operating a pre-crash sensing system for a source vehicle having a source vehicle width and length having a countermeasure system, said method comprising:

• measuring a source vehicle speed;
• measuring a source vehicle acceleration;
• determining a target vehicle distance and target vehicle velocity;
• determining a target vehicle acceleration;
• determining a target vehicle classification with a vision system;
• determining a target vehicle length and target vehicle width corresponding to the target vehicle classification;
• determining an angle between a source vehicle direction and a target vehicle direction;
• determining a danger zone based on the source vehicle length, source vehicle width and object length and object width;
• determining a source vehicle time interval corresponding to the time the source vehicle is within said danger zone as a function of the angle, the source vehicle velocity and the source vehicle acceleration;
• determining a target vehicle time interval corresponding to the time the target vehicle is within said danger zone as a function of the angle, the target vehicle velocity and target vehicle acceleration;
• and
• when the source vehicle time interval coincides with the target vehicle time interval, activating the countermeasure system.