Abstract:
A rear collision warning system ( 10 ) for a target vehicle ( 17 ) and an approaching vehicle ( 18 ) is provided. The rear collision warning system ( 10 ) includes a first transmitter ( 54 ) located on the approaching vehicle ( 18 ) and directed at the target vehicle ( 17 ). The first transmitter ( 54 ) generates a vehicle information signal. A first indicator ( 16 ) located on the target vehicle ( 17 ). A first receiver ( 50 ) electrically coupled to the first indicator ( 16 ) receives the vehicle information signal and transmits a warning signal to the approaching vehicle ( 18 ) when the vehicle information signal is above a predetermined magnitude. A method of performing the same is also provided.

Description:
BACKGROUND OF INVENTION 
     The present invention relates generally to collision warning systems, and more particularly to a method and apparatus for warning both operators of two imminent and potentially collidable vehicles of their close proximity. 
     Collision warning systems are becoming more widely used. Collision warning systems provide a vehicle operator knowledge and awareness of objects or vehicles within a close proximity so as to prevent colliding with those objects. Current collision warning systems are unitary in nature in that they only warn the operator of the vehicle containing the collision warning system of a potential collision. A sensor located on a vehicle, upon sensing an object generates an object detection signal, which is communicated to the operator of that vehicle. 
     Typically, a collision that occurs between two moving vehicles occurs over a short duration of time, that may not be long enough in extent for an operator to react. Reaction time is critical in preventing collisions. The longer the available reaction time, the lower the probability of the collision ever occurring. Some data indicates that half of all collisions between vehicles could be avoided if each driver would initiate his accident avoidance maneuver between one and one half second earlier. A factor that affects operator reaction time is the manner in which a vehicle collision warning system indicates to the operator an impending collision. Other factors are also relevant in preventing a collision such as whether the operator is distracted so as to not visualize or hear a collision-warning signal, which can impede the operator from reacting in time. 
     Current collision warning systems have absorbed some of these potential downfalls by creating large lead times, thereby warning the operator far in advance of a potential collision. Some active collision warning systems have considered interrupting verbal and visual communications within the vehicle or applying the brakes or other countermeasures. Yet other warning systems have considered the use of deceleration brake lights that have widening illumination with decreases in vehicle speed, as to warn rearly approaching vehicles of a nearing decelerating vehicle. 
     The above-mentioned warning systems have several disadvantages. Due to drastically increased warning times the operator of a vehicle may be prematurely warned of a potential collision. The operator, because of the far in advance warning, may find the system to be inaccurate and less likely to heed to the warning signals. Therefore, the above warning systems are limited in their prevention of a collision. The above-mentioned warning systems also do not address closing speed of the approaching vehicle and the likelihood of a collision. 
     Therefore, it would be desirable to provide an improved rear collision warning system. The improved system may increase reaction time and decrease the probability of a collision occurring. 
     SUMMARY OF INVENTION 
     Accordingly, an advantage of the present invention is to provide an improved rear collision warning system for use in an automotive vehicle. 
     The foregoing and other advantages are provided by a method and apparatus for warning both operators of two imminent and potentially collidable vehicles of their close proximity. A rear collision warning system for a target vehicle and an approaching vehicle is provided. The rear collision warning system includes a first transmitter located on the approaching vehicle and directed at the target vehicle. The first transmitter generates a vehicle information signal to a first indicator located on the target vehicle. A first receiver electrically coupled to the first indicator receives the vehicle information signal and transmits a warning signal to the approaching vehicle when the vehicle information signal is above a predetermined magnitude. A method of performing the same is also provided. 
     One of several advantages of the present invention is that it provides a system for not only warning a target vehicle of a potential collision, but also warning an approaching vehicle. 
     Another advantage of the present invention is that it increases the reaction time for both operators of the target vehicle and the approaching vehicle. Thereby, decreasing the probability of a collision between the two vehicles. 
     Additionally, the present invention provides multiple methods of warning both vehicle operators of the potential for a collision, increasing the overall versatility of the rear collision warning system. 
     Furthermore, the present invention provides a method for enacting countermeasures to prevent injury of the vehicle operators in case of a collision. 
     The present invention itself, together with attendant advantages, will be best understood by reference to the following detailed description, taken in conjunction with the accompanying figures. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     For a more complete understanding of this invention reference should now be had to the embodiments illustrated in greater detail in the accompanying figures and described below by way of examples of the invention. 
     FIG. 1 is a schematic view illustrating a sensor implementation technique of a rear collision warning system in accordance with an embodiment of the present invention. 
     FIG. 2 is a schematic view of a wireless communication implementation technique of a rear collision warning system in accordance with another embodiment of the present invention. 
     FIG. 3 is a block diagram of a rear collision warning system in accordance with another embodiment of the present invention. 
     FIG. 4 is a logic flow diagram illustrating a method of preventing a rear collision between an approaching vehicle and a target vehicle, according to an embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION 
     While the present invention is described with respect to a method and apparatus for warning both operators of two imminent and potentially collidable vehicles of their close proximity, the present invention may be adapted to be used in various systems including: forward collision warning systems, collision avoidance systems, vehicle systems, or other systems that may require collision avoidance. 
     In the following description, various operating parameters and components are described for one constructed embodiment. These specific parameters and components are included as examples and are not meant to be limiting. 
     Also, in the following description, the terms “target vehicle” and “approaching vehicle” are relative terms used to reference a vehicle for a particular situation or application of the present invention. By no means do these terms only refer to a certain vehicle position relative to the position of another vehicle. For example, an approaching vehicle may refer to a first vehicle that is approaching a second vehicle from behind or it may refer to the second vehicle that is forward of the first vehicle but is becoming closer to the first vehicle. 
     Referring now to FIG. 1, a schematic view illustrating a sensor implementation technique of a rear collision warning system  10  in accordance with an embodiment of the present invention is shown. The system  10  includes an object detection sensor  12 , a controller  14 , and an indicator  16 , all of which are located on a target vehicle  17 . The object detection sensor  12  senses an approaching vehicle  18 , represented by field lines  20 , and generates a detection signal that is transferred to the controller  14 . The controller  14  determines whether the detection signal is greater than a predetermined magnitude, constituting that the approaching vehicle  18  is within a predetermined distance and/or is accelerating toward or approaching the target vehicle  17 . The controller  14  warns the operator of the approaching vehicle  18  by a warning signal, represented by triangle  22 , via the indicator  16  that the approaching vehicle  18  may potentially collide with the target vehicle  17 . In so doing, the operator of the approaching vehicle  18  may react upon sensing the warning signal  22  and preventing a collision with the target vehicle  17 . In a less sophisticated system the object detection sensor  12  may directly transmit a warning signal to the indicator  16  when the detection signal is above the predetermined magnitude. The use of controller  14  provides added advantages over non-use of the controller  14  that will become more evident in the following description. 
     The object detection sensor  12  may be of various form and style including a radar sensor, a scanning laser radar sensor, a pair of stereo camera sensors, an infrared sensor, an ultrasonic sensor, or other sensor known in the art for detecting an object. The object sensor may be also located in various locations on the target vehicle  17 . 
     Controller  14  is preferably a microprocessor based controller such as a computer having a central processing unit, memory (RAM and/or ROM), and associated inputs and outputs communicating across a bus. Controller  14  may be a portion of central vehicle main control unit or a stand-alone rear collision controller. 
     The indicator  16  may be a pulsating indicator, a light bulb, an LED, a fluorescent light, a brake light, a tail light, a hazard light, a horn, or any other indicator that an operator of a vehicle may sense visually or audibly. The indicator  16  may vary in intensity, amplitude, size, or in a way so as to communicate to an operator of an approaching vehicle  18  that the potential for colliding with the target vehicle  17  is increasing or decreasing depending upon the proximity and/or velocity of the approaching vehicle  18  relative to the target vehicle  17 . 
     Referring now to FIG. 2, a pictorial view of a wireless communication implementation of a rear collision warning system  10 ″ in accordance with another embodiment of the present invention is shown. The system  10 ″ includes a first receiver  50 , a second transmitter  52 , a first controller  14 ″, and a first indicator  16 , all of which are located in the target vehicle  17 . The system  10 ″ also includes a first transmitter  54 , a second receiver  56 , a second controller  58 , and a second indicator  60 , all of which are located in the approaching vehicle  18 . The approaching vehicle  18  continuously transmits an information signal containing information of the location, velocity, and direction of travel of the approaching vehicle  18 . The first controller  14 ″ receives the information signal via the first receiver  50  and determines whether to warn the operator of the approaching vehicle  18  via the indicator  16  and, if so, in what manner. As with the object detection sensor  16  in system  10 , the first receiver  50  may directly transmit a warning signal to the first indicator  16 . The first controller  14 ″ may also transmit a warning signal via the second transmitter  52  to the second receiver  56 , as to communicate the warning signal to the second controller  58 . The second controller  58  may then determine whether, using the second indicator  60 , to warn the operator of the approaching vehicle  18 . 
     The transmitters  52  and  54  and the receivers  50  and  56  may be part of a radar system, a scanning laser radar system, a stereo camera system, an infrared sensing system, an ultrasonic sensing system, or other sensing system known in the art. The transmitters  52  and  54  and the receivers  50  and  56  may also be part of a communication system such as a Bluetooth wireless communication system, an 802.11A wireless communication system, an 802.11B wireless communication system, a satellite wireless communication system, or other communication system. The receivers  50  and  56  may be one of the following type: an AM/FM receiver, a wireless communication system receiver, a telematic system receiver, a global positioning system (GPS) receiver, a satellite receiver, and a navigation system receiver. The receivers  50  and  56  may receive warning signals or approaching vehicle information from either controller  14 ″ or  58 , or a communication system external to both the approaching vehicle  18  and target vehicle  17 . For example, the receivers  50  and  56  may receive position information, of either vehicle  18  or  17 , from global positioning data received as part of a GPS. 
     Controllers  14 ″ and  58  are similar to controller  14 , in system  10 , as to their internal componentry and some potential locations and uses within a vehicle. The controllers  14 ″ and  58  may have additional logic and memory, above that of controller  14 , as to satisfy additional features of system  10 ″. 
     The second indicator  60  may be of various type and style including a computer, an LED display, an LED, a PDA, a light bulb, a heads-up display, an audio system, a video system, or other indicator known in the art. Further explanation of the audio system and the video system is below and best illustrated in FIG.  3 . 
     Referring now to FIG. 3, a block diagrammatic view of a rear collision warning system  10 ″″ in accordance with another embodiment of the present invention is shown. System  10 ″″ includes the transmitters  52  and  54 , receivers  50  and  56 , and indicators  16  and  60  as in system  10 ″. System  10 ″″ also includes a first controller  14 ″″ and a second controller  58 ″, which are similar to controllers  14 ″ and  58 , respectively. Controllers  14 ″″ and  58 ″ may have additional logic and memory, above that of controllers  14 ″ and  58 , for use in system  10 ″″. The system  10 ″″ also includes audio systems  100  and  102 , video systems  104  and  106 , restraint systems  108  and  110 , braking systems  112  and  114 , and fuel and power supply systems  116  and  118  for the target vehicle  17  and the approaching vehicle  18 , respectively. 
     The audio systems  100  and  102  and the video systems  104  and  106  of both the approaching vehicle  18  and the target vehicle  17  may be in communication with the second controller  58 ″ and the first controller  14 ″″, respectively, and be used as an indicator to warn an operator of a potential collision. The audio systems  100  and  102  may include a vehicle stereo system, a computer generated audio system, an entertainment system, and a sound-conveying device. Audio systems  100  and  102  may warn an operator in a verbal format such as a recorded voice, warning tones, and text-to-speech. Video systems  104  and  106  may include a radar display, a data capable phone, a wireless-enabled personal digital assistant, a navigation system, a telematic system, and a video entertainment system. The audio systems  100  and  102  and the video system  104  and  106  convey approaching vehicle information to an operator including proximity, position, velocity, distance, direction of travel, time to impact, and other relative information as to inform the operator of a potential collision. Time to impact refers to the amount of time between a warning signal and a predicted time of collision. The time to impact preferably includes velocity of the approaching vehicle  18  relative to the target vehicle  17 . Time to impact may also include other components such as whether one vehicle is accelerating or not, the distance between the vehicles, or other factors that may effect the probability of the approaching vehicle  18  colliding with the target vehicle  17  in a predicted time frame. 
     The restraints systems  108  and  110  of the approaching vehicle  18  and the target vehicle  17  are enacted by the controllers  14 ″″ and  58 ″ as a countermeasure to protect operators of both vehicles, in case of a collision. The restraint systems  108  and  110  may include a vehicles air bag deployment system containing frontal, side, side curtain, or other vehicle air bags. The restraint systems  108  and  110  may also include pretensioners, seat positioning systems, head restraint systems, or other restraint systems. 
     The controllers  14 ″″ and  58 ″ may also activate the braking systems  112  and  114 , downshift a vehicle transmission (not shown), or deactivate a vehicle fuel system or a portion of a vehicle power supply system in order to reduce traveling velocity of the vehicle and maintain a predetermined distance between the approaching vehicle  18  and the target vehicle  17 . This is another added precautionary measure, of the present invention, in preventing a potential collision. 
     All of the above-mentioned systems and embodiments of the present invention are not meant to be separate all-inclusive systems; they may share components and systems from each other depending upon the application. 
     Referring now to FIG. 4, a logic flow diagram illustrating a method of preventing a rear collision between an approaching vehicle and a target vehicle is shown, in accordance with an embodiment of the present invention. 
     In step  150 , an object detection sensor or a first receiver detects the approaching vehicle and signals a first controller as described above. 
     In step  152 , the first controller determines the proximity of the approaching vehicle relative to the target vehicle. The proximity is determined, using one of several methods including the target vehicle sensing the approaching vehicle, the target vehicle receiving a communication signal from the approaching vehicle, or the target vehicle determining proximity as part of a communication system that is partially external to both the approaching vehicle and the target vehicle. Proximity includes the relative position and distance of the approaching vehicle. The first controller, as stated above, may also determine the velocity and direction of travel of the approaching vehicle relative to the target vehicle, as well as, other factors in determining the probability of a collision between the approaching vehicle and the target vehicle. 
     In step  154 , the first controller continuously monitors the above-mentioned factors and signals the operators of the approaching vehicle and the target vehicle of a potential collision when any of the above mentioned factors are above corresponding predetermined magnitude or threshold levels. Controllers located on the approaching vehicle and the target vehicle then determine, in response to the above factors, whether to enact a countermeasure, and what countermeasures to enact. For example, when the time to impact is less than a particular predetermined duration, a controller may enact a pretensioner to pull the operator of a vehicle further into a driver seat as to aid in preventing operator injury during a collision. The proactive action of the controller activating the pretensioner further indicates to the operator that a collision has a high probability of occurring. 
     The present invention provides an improved rear collision warning system that increases reaction time for both the operator of an approaching vehicle and the operator of a target vehicle. The present invention is passive in that it warns vehicle operators of a potential collision and it is also active in that it activates countermeasures as to prevent a collision from ever occurring. The variety of potential uses and the versatility of the present invention allow it to be used for various purposes having various system and cost requirements. 
     The above-described apparatus, to one skilled in the art, is capable of being adapted for various purposes and is not limited to the following systems: forward collision warning systems, collision avoidance systems, vehicle systems, or other systems that may require collision avoidance. The above-described invention may also be varied without deviating from the spirit and scope of the invention as contemplated by the following claims.