Abstract:
A system and method for suppressing collision warning in a host vehicle is provided. The system receives position data from a remote vehicle. The host vehicle suppresses a collision warning when a detected stationary object is in a safe-zone based on the remote vehicle position data, thereby preventing false collision warnings.

Description:
TECHNICAL FIELD 
       [0001]    The disclosure relates to a method and system for false event suppression of stationary objects in a collision avoidance system. 
       BACKGROUND 
       [0002]    Many vehicles are equipped with sensors and electronics that together help create a collision warning or collision avoidance system. As a vehicle approaches a target which could potentially cause a collision, the sensors receive information about the relationship of the vehicle&#39;s position to the target and issue a warning to the driver. 
         [0003]    In vehicular collision warning systems, the occurrence of false events has the potential to lead to annoyance or even an unsafe situation for the driver of the vehicle. For example, if the driver of the vehicle is constantly getting warnings that are not clearly related to a threatening situation, then this could quickly prove to be annoying and cause the driver to lose confidence in the system. 
         [0004]    One example of a collision avoidance system is disclosed in U.S. Patent Publication No. 2011/0040481. 
       SUMMARY 
       [0005]    In one embodiment, a warning suppression method for a host vehicle is provided. The method includes receiving position data from a remote vehicle. The host vehicle suppresses a collision warning when a detected stationary object is in a safe-zone based on the remote vehicle position data, thereby preventing false collision warnings. 
         [0006]    In another embodiment, the method includes detecting the stationary object with a host vehicle sensor. 
         [0007]    In another embodiment, the method includes determining a host vehicle position when the stationary object is detected. 
         [0008]    In another embodiment, the method includes receiving the collision warning based on a collision system sensor signal. 
         [0009]    In another embodiment, the method includes allowing the collision warning if the stationary object is not within the safe-zone. 
         [0010]    In another embodiment, the method includes monitoring collision threat information of the host vehicle. The host vehicle compares the collision threat information to the safe-zone. 
         [0011]    In one other embodiment, a host vehicle collision warning system is provided. The collision warning system includes a vehicle controller for a host vehicle. The controller is configured receive a collision threat and path data from a remote vehicle. The controller suppresses a collision warning if the collision threat is in a safe-zone based on the remote vehicle path data, thereby preventing false collision warnings. 
         [0012]    In another embodiment, in the controller is also determines a host vehicle position when the collision threat is received. 
         [0013]    In another embodiment, the host vehicle position data includes coordinate data. Likewise, the path data includes a plurality of transmitted coordinate positions of the remote vehicle. 
         [0014]    In another embodiment, the position data comprises a plurality of position data of the remote vehicle. 
         [0015]    In another embodiment, the position data comprises an absolute position data, a heading data, a vehicle length data and a vehicle width data of the remote vehicle. 
         [0016]    In another embodiment, the controller allows the collision warning if the collision threat is not within the safe-zone. 
         [0017]    In one other embodiment, a host vehicle collision warning system is provided. The vehicle collision warning system includes a collision detection sensor. The vehicle collision warning system also includes a receiver for receiving vehicle-to-vehicle communications. A controller in communication with the sensor and the receiver receives a collision threat and path data from a remote vehicle. The controller suppresses a collision warning in the host vehicle if the collision threat is in a safe-zone based on the remote vehicle path data, thereby preventing false collision warnings. 
         [0018]    In another embodiment, the sensor comprises a forward-looking device including at least one of a camera, radar, and lidar. 
         [0019]    In another embodiment, the collision warning system includes a global positioning system (GPS) device to determine a position of the host vehicle. 
         [0020]    The above advantages and other advantages and features will be readily apparent from the following detailed description of the preferred embodiments when taken in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  is a schematic illustration of a collision warning system provided on a vehicle, according to an embodiment; 
           [0022]      FIG. 2  illustrates a stationary object within a vehicle safe-zone according to an embodiment; 
           [0023]      FIG. 3  illustrates a process flowchart for determining if a collision event warning should be suppressed; 
           [0024]      FIG. 4  illustrates a vehicle safe-zone as shown in  FIG. 2  according to one embodiment; and 
           [0025]      FIG. 5  illustrates a vehicle safe-zone as shown in  FIG. 2  according to another embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. 
         [0027]    Often times, the root cause of the false event is that a non-vehicle object that is sensed as a valid target by the collision avoidance system and is then reacted upon. Collision avoidance systems have an easier time identifying moving objects as false targets based on the host vehicle speed and the relative speed to the target. With the speed information, identification and rejection of false moving targets becomes much easier. However, rejecting false stationary targets is more difficult. Collision warning systems have a hard time discriminating between a vehicle and other false stationary targets because the stationary targets have no speed so there is no longer an obvious characteristic distinguishing it from a vehicle. All of a sudden objects like berms, man hole covers, trees and poles all resemble valid targets to the collision avoidance system. It is useful to reduce the instances of false positives if possible, because alarms that are unnecessary can be distracting to the driver. 
         [0028]      FIG. 1  is a schematic illustration of a collision warning system (CWS)  100  that can be provided to a vehicle. As shown, the CWS  100  includes a microprocessor  110  that is operable to process instructions to and from various components of the CWS  100 . This microprocessor  110  could be a dedicated processor or the CWS  100  could share a processor with other vehicle-based systems. 
         [0029]    The CWS  100  may also be provided with one or more vehicle-based sensors  112 . The sensors  112  may include, but are not limited to, radar, laser systems such as lidar, cameras or any other suitable sensing apparatus. For example, a camera or radar system can detect the presence of an obstacle within a projected possible path of a vehicle. As the vehicle approaches the obstacle, additional information about the positioning, size, etc of the obstacle can be gathered by vehicle sensors  112 . If the vehicle&#39;s current heading and speed makes a collision with the object likely or possible, a warning can be given to the driver through a visual display  116  or audio system  118  in communication with the microprocessor  110 . 
         [0030]    In the embodiment illustrated in  FIG. 1 , the CWS  100  is also provided with a communications system  120  such as a vehicle-to-vehicle (V2V) communication system. The CWS  100  may wirelessly communicate with other vehicles regarding their status. Various types of V2V communication systems are know to those of ordinary skill in the art that can be used for vehicles to send pertinent information back and forth to each other. For example, V2V information may be transmitted over a radio frequency. Another example of V2 communication system is Dedicated Short Range Communication (DSRC). V2V broadcast messages include information on surrounding vehicle range, range rate, heading, position, speed and acceleration/deceleration, etc. that can be used in a controller algorithm or CWS  100 . V2V communication systems can provide driving information about multiple vehicles and can also provide greater range of detection. The communications system  120  can communicates with a remote network or server and retrieve remote information for processing by the microprocessor  110  for rejecting false stationary targets by utilizing vehicle-to-vehicle communications data. Position tracks of surrounding vehicles that are equipped with V2V communications systems can be monitored to create zones of roadway have been driven over in the recent past. 
         [0031]    By compiling communications data from other vehicles with V2V communication systems, a map of zones without stationary objects may be created. If the host vehicle&#39;s CWS  120  subsequently detects a stationary target through one of the sensors  122 , the position of the target can be cross referenced to these zones. If the position of the target falls within an area that has just been driven over by the remote vehicle with a V2V communication system, it can be inferred that the target is then a false target, such as a man hole cover or an overhead sign. 
         [0032]    The CWS  100  may also be equipped a global positioning system (GPS)  122 . The GPS  122  can be used to record the location of the host vehicle when an object is detected. It can also be used in combination with stored map data to determine the vehicle&#39;s position, or vehicle heading on a particular road as a detected obstacle is approached. 
         [0033]    The CWS  100  provides a way of identifying zones of roadway that are highly unlikely to contain valid stationary obstacles by monitoring the path histories, positions, headings and velocities of surrounding vehicles that are equipped with a vehicle to vehicle communications system. These zones will be referred to as safe-zones without stationary objects. 
         [0034]      FIG. 2  shows a common roadway scenario where a lead vehicle  130  has just crossed over a manhole cover  132  with a trailing host vehicle  136  following. For a CWS  100 , such as a radar based system, there is a possibility that the manhole cover  132  will be detected or sensed as a valid stationary obstacle for the trailing host vehicle  136 , especially since manhole covers are difficult to distinguish from vehicles for a radar-based CWS. Subsequently, the CWS  100  in the host vehicle  136  may issue a false warning event. 
         [0035]    To prevent false warning events from occurring, the other surrounding vehicles that are equipped with a V2V system can be monitored to determine where they have been in the recent past. From this path history information of remote vehicle  130 , the CWS  100  can determine safe-zones  140  without stationary objects on the roadway. Once a safe-zone  140  has been determined, any stationary object  132  that is detected within the safe-zone  140  would be rejected, since it is highly probable that the stationary object in the safe-zone  140  is an invalid object, such as a manhole cover of a metal grate, as shown in  FIG. 2 . 
         [0036]      FIG. 3  illustrates a method  300  for determining if a collision event warning should be suppressed. As those of ordinary skill in the art will understand, the functions represented by the flowchart blocks can be performed by software and/or hardware. Also, the functions can be performed in an order or sequence other than that illustrated in  FIG. 3 . Similarly, one or more of the steps or functions can be repeatedly performed although not explicitly illustrated. Likewise, one or more of the representative steps of functions illustrated can be omitted in some applications. In one embodiment, the functions illustrated are primarily implemented by software instructions, code, or control logic stored in a computer-readable storage medium and if executed by a microprocessor based computer or controller such as the controller  110 . 
         [0037]    The CWS  100  monitors potential collision threats, as represented by block  310 . The CWS may determine that a non-vehicle stationary object is causing a threatening situation, by looking at the absolute position of the host vehicle and the range to the object and the azimuth angle to the object, for example. The current absolute position of a potential collision threat, such as a stationary object can be determined as the vehicle monitors for threatening situations in block  310 . 
         [0038]    Next, the vehicle-to-vehicle data of surrounding vehicles is received, as represented by block  312 . The V2V data may include the absolute positions, headings, length and width of the surrounding V2V vehicles. The V2V data may also include path history bread crumbs and width of the surrounding V2V vehicles, for example. 
         [0039]    Based on the remote vehicle data in block  312 , the safe-zones without stationary objects are determined, as represented by block  314 . The safe-zones are determined based on the V2V data of the surrounding vehicles. This will be described in greater detail in  FIG. 4  and  FIG. 5 . 
         [0040]    Next, the threat information in is compared to the safe-zones, as represented by block  316 . The threat information was determined in step  310  and likewise, the safe-zones were determined in step  312 . 
         [0041]    Next it must be determined if the threatening stationary non-vehicle object is within the safe-zone, as represented by block  318 . This is done by comparing the absolute position of the stationary object to the safe-zones. The detected objects are within any of the safe zones of remote vehicles, the detected object is highly unlikely to be a vehicle collision, so the controller may suppress the event and prevent a collision warning, as represented by block  320 . 
         [0042]    If the detected object is outside of the safe-zones without stationary objects, then the controller can allow the event, as represented by block  322 . If the event is allowed, no determination of the likely hood that the object is a false target can be obtained so the collision avoidance system can warn the driver of a potential threat. 
         [0043]    Turning now to  FIGS. 4 and 5 , the method of determining safe-zone of a remote vehicle  410  is illustrated. In  FIG. 4 , the safe-zone is determined by using the position  420 , the heading  422 , the length  424  and width  426  of the remote vehicle  410  to determine the four corners  430  of the remote vehicle  410  at any moment as gathered in vehicle-to-vehicle data. The four corners define a bounding box  434  of a zone free of stationary objects for the current moment. These bounding boxes  434  are then maintained for a specified period of time, so a number of sample times, such that each for each sample time a new box  434  is drawn. Overtime, the compilation of bounding boxes  434  defines the safe-zone  440  without stationary objects, as shown in  FIG. 4 . The safe-zone  440  without stationary objects illustrated in  FIG. 4  defines a geometric-shaped trajectory of the remote vehicle  410 . 
         [0044]      FIG. 5  illustrates another embodiment for determining zones that are free of stationary objects. Like in  FIG. 4 , the safe-zone is determined by using the position  420 , the heading  422 , the length  424  and width  426  of the remote vehicle at any moment as gathered in vehicle-to-vehicle data. The path history breadcrumbs  450  of the remote vehicle  448  represent where the remote vehicle  448  has been. Half the width  452  of the vehicle is applied to either side of the breadcrumb  450  at a current moment. The safe-zone  256  is defined when the breadcrumbs  450  and vehicle width  452  are then maintained for a duration of time. The safe-zone  256  without stationary objects illustrated in  FIG. 5  defines a smoothed trajectory of the remote vehicle  448 . 
         [0045]    While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.