Inter-vehicle distance measuring apparatus and method for automotive

An inter-vehicle distance measuring apparatus for an automotive vehicle comprising:

• a communications unit for receiving a reference signal transmitted from external transmitting means;
• inter-vehicle distance measuring means for measuring a time difference from the time a measuring signal is transmitted to the time said measuring signal, reflected back from a vehicle in front, is received by counting clock signals from a clock signal generator to measure a distance between said vehicle in front and a host vehicle;
• and
• means for correcting the period of said clock signal generated by said clock signal generator of said inter-vehicle distance measuring means, based on said reference signal received by said communications unit.

An inter-vehicle distance measuring apparatus for an automotive vehicle comprising:

• means for previously storing a position on a road at which marker means placed at a predetermined position by the road or on the road exists and a fixed distance from said predetermined position to a target member;
• position detecting means for detecting said predetermined position based on said marker means;
• inter-vehicle distance measuring means for measuring a distance between a vehicle in front and a host vehicle as well as for measuring a distance between said target member and the host vehicle;
• correction amount determining means for calculating a correction amount used to correct the distance to said target member measured by said inter-vehicle distance measuring means based on said fixed distance stored in said storing means, when said position detecting means detects said predetermined position;
• and
• inter-vehicle distance correcting means for correcting the distance between the vehicle in front and the host vehicle measured by said inter-vehicle distance measuring means based on the correction amount calculated by said correction amount determining means.

An inter-vehicle distance measuring method for an automotive vehicle comprising the steps of:

• receiving inter-vehicle data related to a distance between a vehicle in front and a host vehicle, transmitted from an inter-vehicle data measuring and transmitting apparatus installed by a road or in the surface of the road;
• measuring a distance between the vehicle in front and the host vehicle;
• calculating a correction amount for correcting said measured distance between the vehicle in front and the host vehicle based on said measured distance between the vehicle in front and the host vehicle and said received inter-vehicle data;
• and
• correcting said measured distance between the vehicle in front and the host vehicle based on said calculated correction amount.

An inter-vehicle distance measuring method for an automotive vehicle, comprising the steps of:

• previously storing a position on a road at which marker means placed at a predetermined position by the road or on the road exists and a fixed distance from said predetermined position to a target member;
• detecting said predetermined position based on said marker means;
• measuring a distance to said target member when said predetermined position is detected at said detecting step;
• calculating a correction amount used to correct the distance between said marker means and said target member measured at said target measuring step, based on said fixed distance stored at said storing step;
• measuring a distance between a vehicle in front and a host vehicle;
• and
• correcting the distance between the vehicle in front and the host vehicle measured at said inter-vehicle distance measuring step, based on the correction amount calculated at said correction amount calculating step.