Collision warning system

Claim 2

A collision warning system mounted on a vehicle to issue an alarm when the vehicle approaches near an obstacle, said system comprising: means for detecting the speed (Vf) of the vehicle; means for measuring the distance (R) between the vehicle and the obstacle; means for deriving a speed (Va) of the obstacle using both said speed (Vf) and said distance (R); means for determining whether the following relationship exists between the vehicle and the obstacle: Vf×Td+(Vf-Va).sup.2 /2α≧R wherein: Vf: said speed of the vehicle, Td: a time period, Va: said speed of the obstacle, α: a braking performance of the vehicle, R: said distance between the vehicle and the obstacle; and means for issuing an alarm to the driver when said relationship exists.

Claim 3

A collision warning system as claimed in claim 1, further comprising means for setting said time period (Td) to zero when a brake pedal of the vehicle is depressed a given amount.

Claim 4

A collision warning system as claimed in claim 1, wherein said means for detecting said speed (Vf) of the vehicle is a vehicle speed sensor mounted on the vehicle.

Claim 5

A collision warning system as claimed in claim 3, wherein said means for measuring said distance (R) comprises a laser beam emitting device mounted on the vehicle.

Claim 6

A collision warning system as claimed in claim 4, wherein said means for deriving uses the following equation for the derivation of said speed (Va) of the obstacle: Va=Vf-dR/dt wherein: Va: said speed of the obstacle, Vf: said speed of the vehicle, dR/dt: relative speed between the vehicle and the obstacle.

Claim 7

A collision warning system as claimed in claim 1, wherein said time period (Td) is the time period which elapses from the time when a driver notices the issuance of the alarm to the time the driver actuates the brake pedal.

Claim 8

A collision warning system mounted on a vehicle to issue an alarm when the vehicle approaches near an obstacle in front of the vehicle, said system comprising: means for setting a time period (Td) which elapses from a time when a driver notices a danger to a time when the driver actuates a brake pedal of the vehicle; means for detecting the speed (Vf) of the vehicle; laser beam emitting means for measuring the distance (R) between the vehicle and the obstacle; means for deriving the speed (Va) of the obstacle using the following equation: Va=Vf-dR/dt wherein: Va: said speed of the obstacle, Vf: said speed of the vehicle, dR/dt: relative speed between the vehicle and the obstacle, means for determining whether the following relationship exists between the vehicle and the obstacle: Vf×Td+(Vf-Va).sup.2 /2α≧R wherein: Vf: said speed of the vehicle, Td: said time period, Va: said speed of the obstacle, α: braking performance of the vehicle, R: said distance between the vehicle and the obstacle; and alarm means for giving an alarm to the driver when the relationship exists.

Claim 9

A collision warning system mounted on a vehicle to issue an alarm when the vehicle approaches near an obstacle in front of the vehicle, said system comprising: means for setting a time period (Td) which elapses from a time when a driver notices a danger to a time when the driver actuates a brake pedal of the vehicle; means for detecting the speed (Vf) of the vehicle; laser beam emitting means for measuring the distance (R) between the vehicle and the obstacle; means for deriving the speed (Va) of the obstacle using the following equation: Va=Vf-dR/dt wherein: Va: said speed of the obstacle, Vf: said speed of the vehicle, dR/dt: relative speed between the vehicle and the obstacle, means for determining whether the following relationship exists between the vehicle and the obstacle: Vf×Td+(Vf-Va).sup.2 /2α≧R wherein: Vf: said speed of the vehicle, Td: said time period, Va: said speed of the obstacle, α: braking performance of the vehicle, R: said distance between the vehicle and the obstacle; and alarm means for giving an alarm to the driver when the relationship exists.

Claim 10

A collision warning system mounted on a vehicle to issue an alarm when the vehicle approaches near an obstacle in front of the vehicle, said system comprising: first means for setting a time period (Td) which elapses from a time when a driver notices a danger to a time when the driver actuates a brake pedal of the vehicle; second means for detecting the speed (Vf) of the vehicle; third means for measuring a distance (R) between the vehicle and the obstacle; fourth means for deriving the speed (Va) of the obstacle using the following equation: Va=Vf-dR/dt wherein: Va: said speed of the obstacle, Vf: said speed of the vehicle, dR/dt: relative speed between the vehicle and the obstacle, fifth means for determining whether the following relationship exists between the vehicle and the obstacle: Vf×Td+(Vf-Va).sup.2 /2α≧R wherein: Vf: said speed of the vehicle, Td: said time period, Va: said speed of the obstacle, α: braking performance of the vehicle, R: said distance between the vehicle and the obstacle; sixth means for giving an alarm to the driver when said relationship exists; and seventh means for setting said time period (Td) to zero when the brake pedal has been depressed before said fifth means determines whether said relationship exists.

Claim 11

A collision warning system mounted on a vehicle to issue an alarm when the vehicle approaches near an obstacle in front of the vehicle, said system comprising: first means for setting a time period (Td) which elapses from a time when a driver notices a danger to a time when the driver actuates a brake pedal of the vehicle; second means for detecting the speed (Vf) of the vehicle; third means for measuring a distance (R) between the vehicle and the obstacle; fourth means for deriving the speed (Va) of the obstacle using the following equation: Va=Vf-dR/dt wherein: Va: said speed of the obstacle, Vf: said speed of the vehicle, dR/dt: relative speed between the vehicle and the obstacle, fifth means for determining whether the following relationship exists between the vehicle and the obstacle: Vf×Td+(Vf-Va).sup.2 /2α≧R wherein: Vf: said speed of the vehicle, Td: said time period, Va: said speed of the obstacle, α: braking performance of the vehicle, R: said distance between the vehicle and the obstacle; sixth means for giving an alarm to the driver when said relationship exists; and seventh means for setting said time period (Td) to zero when the brake pedal has been depressed before said fifth means determines whether said relationship exists.