Abstract:
A method for operating a pre-crash sensing system for a vehicle having an object detecting system and an associated data storage. The method includes partitioning the vehicle operating environment into a plurality of zones wherein each zone represents a different area surrounding the vehicle. In response to detecting an object within any one of the zones, the method activates the zone, and modifies an state of the object detection system and the contents of,the data storage as a function. the active zone. In one embodiment, three zones are disclosed wherein each zone represents a spheroidal area surrounding the vehicle. When the furthest zone is active, all data within the data storage is given approximately equal processing priority. When the middle zone is active, the content of the data storage is modified to prioritize data regarding the detected object for processing. Finally, when the nearest zone is active, the content of the data storage is further modified to provide highest priority to data regarding the detected object.

Description:
BACKGROUND OF INVENTION 
     The present invention relates to pre-crash sensing systems for automotive vehicles, and more particularly, to pre-crash sensing systems having spheroidal partitioning for real-time safety threat assessment. 
     Auto manufacturers are investigating radar, lidar, and vision-based pre-crash sensing systems to improve occupant safety. Current vehicles typically employ accelerometers that measure forces acting on the vehicle body. In response to accelerometers, airbags or other safety devices are employed. Also, Global Position Systems (GPS) are used in vehicles as part of navigation systems. 
     In certain crash situations, it would be desirable to provide information to the vehicle operator before forces actually act upon the vehicle. As mentioned above, known systems employ combinations of radar, lidar and vision systems to detect the presence of an object in front of the vehicle a predetermined time before an actual crash occurs. Such systems have expense constraints and can be prone to false positives. 
     Other systems broadcast their positions to other vehicles where the positions are displayed to the vehicle operator. The drawback to this type of system is that the driver is merely warned of the presence of a nearby vehicle without more. In a crowded traffic situation, it may be difficult for a vehicle operator to react to a crowded display. 
     Information processing and bandwidth for communications can also limit safety applications. As more sensing devices are implemented, the signals generated must be processed, actions determined, and control signals communicated to safety modules having their own reaction latency. For example, airbag deployment, seatbelt pretensioning, nose dipping and braking have latencies of approximately 100 ms, 180 ms, 300 ms and 400 ms, respectively. Having an intelligent methodology which can learn and make efficient use of processing cycles, available data and communication bandwidth is desirable for a robust in-vehicle threat assessment. 
     It would be desirable to provide a system that takes into consideration the position of other vehicles and provides adequate warning to the vehicle operator and, should the situation warrant, provides crash mitigation. 
     SUMMARY OF INVENTION 
     The present invention provides an improved pre-crash sensing-system using spheroidal partitioning of the vehicle environment to warn the vehicle operator and respond to detected objects. 
     In one aspect of the invention, a method for operating a pre-crash sensing system for a vehicle having an object detecting system and an associated data storage is provided. The method includes partitioning the vehicle-operating environment into a plurality of zones wherein each zone represents a different area surrounding the vehicle. In response to detecting an object within any one of the zones, the method activates the zone, and modifies an operating state of the object detection system and the contents of the data storage as a function the active zone. In one embodiment, three zones are disclosed wherein each zone represents a spheroidal area the vehicle. When the furthest zone is active, all data within the data storage is given approximately equal processing priority. When the middle zone is active, the content of the data storage is modified to prioritize data regarding the detected object for processing. Finally, when the nearest zone is active, the content of the data storage is further modified to provide highest priority to data regarding the detected object. 
     One advantage of the invention is that the spheroidal portioning of the vehicle environment allows for prioritizing data processing and communication. This reduces the amount of unnecessary information exchanged and therefore communication is expedited allowing more time for the vehicle operator or countermeasure device to react to a detected object. 
     Other aspects and features of the present invention will become apparent when viewed in light of the detailed description of the preferred embodiment when taken in conjunction with the attached drawings and appended claims. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     For a more complete understanding of this invention, reference should now be made to the embodiments illustrated in greater detail in the accompanying drawings and described below by way of examples of the invention. 
     FIG. 1 is a block diagrammatic view of a pre-crash sensing system according to one embodiment of the present invention. 
     FIG. 2 is a block diagrammatic view of one embodiment of the invention illustrating a vehicle network established by two pre-crash sensing systems. 
     FIG. 3 is a perspective view of an automotive vehicle instrument panel display for use with the present invention. 
     FIG. 4 is a front view of a vehicle network display according to an embodiment the present invention. 
     FIG. 5 is a schematic diagram of a spheroidal partition of a vehicle environment according to an embodiment of the present invention. 
     FIG. 6 is a block diagram of a spheroidal threat assessment system according to the present invention. 
     FIG. 7 is a logic flow diagram of the operation of the spheroidal threat assessment system of FIG.  6 . 
    
    
     DETAILED DESCRIPTION 
     In the following figures, the same reference numerals will be used to identify the same components in the various views. 
     Referring now to FIG. 1, a pre-crash sensing system  10  for an automotive vehicle  11  has a controller  12 . Controller  12  is preferably a microprocessor-based controller that is coupled to a memory  14 . Controller  12  has a corresponding CPU that is programmed to perform various tasks, as well as inputs/outputs and a communications bus. Memory  14  is illustrated as a separate component from that of controller  12 . However, those skilled in the art will recognize that memory may be incorporated into controller  12 . 
     Memory  14  may comprise various types of memory including read only memory, random access memory, electrically erasable programmable read only memory, and keep alive memory. Memory  14  is used to store various thresholds and parameters including vehicle data  16  as illustrated. 
     Controller  12  is coupled to a global positioning system (GPS)  18  that receives position data triangulated from satellites as is known to those skilled in the art. 
     Controller  12  is coupled to a sensor data block  20  that represents various sensors located throughout the vehicle. The various sensors will be further described below. 
     Controller  12  may also be coupled to a receiver  22  coupled to a receiving antenna  24  and a transmitter  26  coupled to a transmitting antenna  28 . Transmitter  26  and receiver  22  may be part of a transponder  27 . Transponder  27  can be located at the front of the vehicle  11 . Preferably, vehicle has a transponder located on each of the four sides of the vehicle. That is, a rear transponder is located at the rear of the vehicle, a transponder is located on the left side of the vehicle and, a transponder is located on the right side of the vehicle. A radar sensor  29  is located within each transponder. When a radar signal having a certain amplitude is detected, transmitter  26  generates a response that includes its location relative to the vehicle. Other data such as sensor data, position data, and other data may also be communicated. An example of a radar signal is a cruise control signal from an active cruise control system. 
     Controller  12  is also coupled to a display  30  that may include various types of displays including a vehicle network display, a warning display  34 , and a counter-measure display  36 . An example of a network display will be described in further detail below. As should be noted, display  30  may be a single display with different display features or may be individual displays that may include audible warnings as well. 
     Controller  12  has various functional blocks illustrated within CPU  13 . Although these functional blocks may be represented in software, they may also be implemented in hardware. As will be further described below, controller  12  has a proximity detector  42  that is used to determine the proximity of the various vehicles around automotive vehicle  11 . A vehicle trajectory block  44  is used to determine the trajectory of the vehicle and surrounding vehicles. Based upon the vehicle trajectory block  44 , a threat assessment is made in functional block  46 . Of course, threat assessment  46  takes into consideration various vehicle data  16  and sensor data from sensor block  20 . Threat assessment  46  may be made based upon the braking capability of the present vehicle and surrounding vehicles in block  48  and also road conditions of the present vehicle and surrounding vehicles in block  50 . As will be further described below, the road conditions of block  50  may be used to determine the braking capability in block  48 . 
     In block  16 , various vehicle data are stored within the memory. Vehicle data represents data that does not change rapidly during operation and thus can be fixed into memory. Various information may change only infrequently and thus may also be fixed into memory  14 . Vehicle data includes but is not limited to the vehicle type, which may be determined from the vehicle identification number, the weight of the vehicle and various types of tire information. Tire information may include the tire and type of tread. Such data may be loaded initially during vehicle build and may then manually be updated by a service technician should information such as the tire information change. 
     Global positioning system (GPS)  18  generates a position signal for the vehicle  11 . Global positioning system  18  updates its position at a predetermined interval. Typical interval update periods may, for example, be one second. Although this interval may seem long compared to a crash event, the vehicle position may be determined based upon the last update from the GPS and velocity and acceleration information within the vehicle. 
     Global positioning system  18  has a clock that is common to all GPS. Clock  19  provides a timing signal. Each of the GPS for different vehicles uses the same clock and timing signal. As will be described below, the common clock for timing signal is used to synchronize the communication between the various vehicles of the system. 
     Sensor data  20  may be coupled to various sensors used in various systems within vehicle  11 . Sensor data  20  may include a speed sensor  56  that determines the speed of the vehicle. Speed sensor may for example be a speed sensor used in an anti-lock brake system. Such sensors are typically comprised of a toothed wheel from which the speed of each wheel can be determined. The speed of each wheel is then averaged to determine the vehicle speed. Of course, those skilled in the art will recognize that the vehicle acceleration can be determined directly from the change in speed of the vehicle. A road surface detector  58  may also be used as part of sensor data  20 . Road surface detector  58  may be a millimeter radar that is used to measure the road condition. Road surface detector  58  may also be a detector that uses information from an anti-lock brake system or control system. For example, slight accelerations of the wheel due to slippage may be used to determine the road condition. For example, road conditions such as black ice, snow, slippery or wet surfaces may be determined. By averaging microaccelerations of each tire combined with information such as exterior temperature through temperature sensor  60 , slippage can be determined and therefore the road conditions may be inferred therefrom. Such information may be displayed to the driver of the vehicle. The surface conditions may also be transmitted to other vehicles. 
     Vehicle data  16  has a block  52  coupled thereto representing the information stored therein. Examples of vehicle data include the type, weight, tire information, tire size and tread. Of course, other information may be stored therein. 
     Sensor data  20  may also include a tire temperature sensor  62  and a tire pressure sensor  64 . The road condition and the braking capability of the vehicle may be determined therefrom. 
     Other system sensors  66  may generate sensor data  20  including steering wheel angle sensor, lateral acceleration sensor, longitudinal acceleration sensor, gyroscopic sensors and other types of sensors. 
     Referring now to FIG. 2, vehicle  11  may be part of a network  70  in conjunction with a second vehicle or various numbers of vehicles represented by reference numeral  72 . Vehicle  72  preferably is configured in a similar manner to that of vehicle  11  shown in FIG.  1 . Vehicle  72  may communicate directly with vehicle  11  through transmitter  26  and receiver  22  to form a wireless local area network. The network  70  may also include a repeater  74  through which vehicle  11  and vehicle  72  may communicate. Repeater  74  has an antenna  76  coupled to a transmitter  78  and a receiver  80 . Various information can be communicated through network  70 . For example, vehicle data, position data, and sensor data may all be transmitted to other vehicles throughout network  70 . 
     Referring now to FIG. 3, an instrument panel  82  is illustrated having a first display  84  and a second display  86 . Either displays  84 ,  86  may be used generate various information related to the pre-crash sensing system. 
     Referring now to FIG. 4, display  84  is illustrated in further detail. Display  84  can be configured to correspond to the vehicle network display warning display and countermeasure display mentioned above. The vehicle network display  32  may include a map  88 , a first vehicle indicator  90 , and a second vehicle indicator  92 . First vehicle indicator corresponds to the driven vehicle having the present pre-crash sensing system, while vehicle indicator  92  corresponds to an approaching vehicle. Vehicle network display  32  may be displayed when a vehicle is near but beyond a certain distance or threat level. The vehicles on the display may be those within the field of view or those broadcasting signals as will be described below. 
     Warning indicators and distance indicators can also be displayed to provide the vehicle operator with an indication of the distance from a detected vehicle or object. The display may indicate a warning when the vehicle is within a predetermined distance or when an urgent threat level exists. 
     Display  84  can also be configured to a counter-measure display to indicate to the vehicle operator that a counter-measure is being activated because the threat level is high or the distance from the vehicle is within a predetermined distance less than the distances needed for activation of the vehicle network display or warning display. 
     Display  84  is a screen-based display such as an LCD, LED, or CRT display, or may be implanted as a heads-up display (HUD) overlaying the forward vision of the vehicle operator to through the windshield. Other known display mechanisms as also contemplated by the present invention. 
     Referring now to FIG. 5 there is shown a schematic diagram of a spheroidal partition of a vehicle environment according to an embodiment of the present invention. Display  84  or display  86  can be configured to depict a “birds-eye” field of view or overhead field of view for vehicle  11  to communicate information regarding a surrounding environment to the vehicle operator. The environment surrounding the vehicle  11  is divided into three threat assessment zones identified as red zone  200  (T R ), yellow zone  202  (T Y ), and green zone  204  (T G ). Each of the zones  200 ,  202 , and  204  are concentric with the vehicle  11 . Similar concentric zones exist for vehicles similarly equipped with a pre-crash threat assessment system. Preferably, the zones are spheroidal and three-dimensional to help determine whether vehicles which appear to be on the same plane are about to collide, such as at an intersection; or whether the vehicles are traveling in different planes, such as when one of the vehicles is on an overpass and does not pose a collision threat with any otherwise adjacent vehicle. The three dimensional information is obtained from the GPS sensing system. 
     Each of the green, yellow, and red zones describes the temporal relationships surrounding the vehicle  11  and is based on multi-varied information such as vehicle speed, headway distance between other vehicles, geographic information, and driver characteristics, for example. 
     The green zone  204  represents a low risk zone with long temporal scales. For example, the green zone may represent the region between approximately 30 m and 50 m from the vehicle of interest. In this region, adjacent vehicles are interacting weakly by way of a virtual floating network (FIG. 2) through transponders located on the vehicles. In the green zone  204 , information is shared between nearby vehicles enabling traffic monitoring and rerouting, for example, as is necessary or desirable. The green zone  204  is considered a very low threat zone. 
     The yellow zone  202  represents a moderate risk with temporal scales on the order of approximately one to five seconds. The yellow zone may represent, for example, a region between 10 m and 30 m from the vehicle  11 . The threat assessment data is fundamentally different in this region as compared to the green zone  204 . Thus, the update and/or refresh rates for the sensors communicating threat assessment data as well as the communication of the respective data occur on faster time scales than in the green zone. For adjacent vehicles, a time-to-collision value between vehicles in close proximity acts as a time boundary within which threat assessments and, if necessary, countermeasure deployment must occur. Accordingly, data communicated on the vehicle network is prioritized such that the most important data is processed first whereas other types of data are given less priority such as navigational data, entertainment data, or other types of convenience items. 
     Inside the red zone  200 , the network is focused only on communication between vehicles in very local proximity representing an impending threat. Thus, there occurs a further data priority as compared to the yellow zone  202 . Red zone may represent, for example, the region within 10 m surrounding the vehicle  11 . Threat assessment data is filtered and processed based upon identification of the threatening vehicle. If the potentially threatening vehicle  206  is communicating wirelessly with the vehicle  11 , the resulting data is processed at the fastest rate and given highest priority. If, however, adjacent vehicle  206  is not wirelessly equipped to communicate with vehicle  11 , the sensor or sensor group of vehicle  11  which can uniquely identify vehicle  206  is used and given priority. The type and location data of vehicle  206  is given highest priority in the threat assessment controller of vehicle  11  and monitored continually until an event changes the priority selection for the detected vehicle  206 . 
     The spheroidal partitioning of the vehicle environment for vehicle  11  may be configured such that actions may be taken as corresponding zones of an adjacent vehicle interfere with or are detected within the green, yellow, and red zones  204 ,  202 ,  200  of vehicle  11 . Thus, when the red zone  208  of vehicle  206  impinges upon the red zone  200  of vehicle  11 , actions may be taken. Alternatively, vehicle  206  could be considered to be only within the yellow zone  202  of vehicle  11 . Likewise, forward vehicle  210  could be considered to be in the yellow zone  202  of vehicle  11 , or entirely outside the green zone  204  of vehicle  11  depending upon the configuration of the areas represented by the respective zones. 
     In summary, the green zone is characterized by a virtual floating network between all adjacent vehicles and represents a relatively low risk of impact with a detected object due to the long temporal scales involved such as greater than 5 seconds. To the extent that any modification is desired of the vehicle trajectory, it can be accomplished by braking or rerouting suggestions as the vehicles are only weakly interacting with each other. The yellow zone represents a more moderate impact risk wherein reactions are occurring on a scale of between approximately 1 second and 5 seconds. In the yellow zone, the virtual floating network is more properly characterized as a peer-to-peer network between the vehicle  11  and the detected vehicle or object of interest within the yellow zone. In such cases, the vehicle  11  can be said to be moderately interacting with the detected vehicle or object. In order to avoid impending collision, hard maneuvering, for example, may be required. In the red zone, the threat assessment is characterized as high risk due to the short time to impact of approximately less than 1second. In such cases, smart transponders on the vehicle  11  are given highest priority for continuous threat assessment and mitigation in the form of, for example, active countermeasures. In such cases, the vehicle  11  can be said to be strongly interactive with a detected object or vehicle. 
     Referring now to FIG. 6 there is shown a block diagram of a spheroidal threat assessment system according to an embodiment of the present invention. The control scheme is governed by the processing control unit (PCU)  300  such as the controller  12  of FIG.  1 . The PCU is in operative communication with a data repository  302 , the content of which is a function of the surveillance zone (green, yellow or red) active at a given moment in time. The data repository  302  thus can contain information from the in-vehicle data warehouse  304 , wireless data from other vehicles  306  as well as navigational data  308  from the GPS or wireless network. The in-vehicle data warehouse  304  contains the vehicle data  16  and sensor data  20  (FIG.  1 ). The wireless data from other vehicles  306  potentially represents the most critical data source for impact assessment and mitigation since it is enabled by vehicle-to-vehicle communication. Transponder information from transponder  27  can be used to further enhance the information warehouse  304 . By aggregating the information and comparing differences between in-vehicle data and shared data, the PCU  300  can determine uniquely the surrounding vehicles, sensing technologies, location, and threat potential of detected objects. 
     Depending upon whether the red zone  200 , yellow zone  202 , or green zone  204  is active, different actions are taken as mentioned above. Thus, the green actions  312  include continued information sharing through network telematics  314  to allow for traffic monitoring and rerouting, for example. Yellow actions  316  include prioritizing data within the data repository  302  based upon the time-to-collision of the detected object or vehicle. Data prioritization may include increasing the update and/or refresh rates for the sensors as well as the speed at which communicated data occurs. Data prioritization may also include processing more important data first and moving other data to background processing such as navigational data or entertainment related data. A peer-to-peer network may also be established between the vehicle and the detected vehicle such that mitigating action may be taken in either the driven vehicle or the detected vehicle or both. A yellow action  316  may also result in a warning  318  being displayed within the vehicle. 
     Red actions  320  include further prioritization of the data repository  302  to filter and process specific data based upon the identification of the detected object or vehicle. Thus, vehicle trajectory data and type and location data is given the highest priority within the PCU  300  and the sensor or sensor set uniquely associated with providing such information is given the highest priority as well. If an impact with a detected object or vehicle is eminent, red actions  320  may include active or passive countermeasures  322 . 
     The green and yellow actions  312 ,  316  may also transition to a higher priority (red zone surveillance) based upon actions of the vehicle operator in addition to events on the road or with respect to detected objects. For example, referring again to FIG. 5, vehicle  206  in the process of merging into the lane of vehicle  11  would interact strongly with vehicle  11  and depending upon the trajectory of vehicle  206  and rate of change of trajectory, a green zone interaction may change to a yellow zone or a green zone interaction may change directly to a red zone. Similarly, if vehicle  210  was in the green zone of surveillance and the operator of vehicle  11  was, for example, to start talking on the telephone, the green zone surveillance may change to a yellow zone due to the diversion of the driver&#39;s attention from the road. In this way, a heightened sense of awareness between vehicle  210  and vehicle  11  can augment the vehicle operator&#39;s ability to focus at the task of driving the vehicle  11 . 
     Referring now to FIG. 7, a logic flow diagram of the operation of the spheroidal threat assessment system of FIG. 6 is shown. In step  400 , the various sensor data for the system is determined. This includes the sensor data  20  (FIG.  1 ). In step  402 , all the vehicle data is determined such as in included in vehicle data  16  (FIG.  1 ). In step  404 , the first GPS signal is obtained for the vehicle. In step  406 , upon the detection of a second vehicle or object within a zone of surveillance, information regarding the second vehicle or object is received from the second vehicle or obtained through sensor detection on the operator&#39;s vehicle. The second vehicle information may be various information such as the speed, heading, vehicle type, position, and road conditions from the other vehicle or vehicles in the network. In step  408 , the proximity of the first vehicle with respect to the second vehicle is determined. The proximity may be merely a distance calculation. In step  410 , the first vehicle trajectory relative to the second vehicle is determined. The first vehicle trajectory uses the information such as the positions and various sensors to predict a path of expected travel for the first vehicle and the second vehicle. In step  412 , a threat assessment of the first vehicle trajectory relative to the second vehicle trajectory is determined. The threat assessment can be categorized based upon the severity of or the immediately of the perceived threat of impact. The threat is preferably scaled to provide various types of warning to the vehicle operator as well as the countermeasure system and threat assessment system. 
     The threat assessment may be made based upon conditions of the vehicle trajectory and vehicle type as well as based upon tire information which may provide indication as to the braking capability of the first vehicle and/or the second vehicle. Thus, the threat may be adjusted accordingly. Also, the road surface condition may be factored into the threat assessment. On clear, dry roads, a threat may not be as eminent as if the vehicle is operating under the same conditions on a wet or snowy road. 
     Based upon the assessed threat, the appropriate surveillance zone is determined in step  414 . Thus, based primarily upon the proximity of the second vehicle, the zone  416 , yellow zone  418  or red zone  420  will become active. In addition or alternatively, based upon the vehicle operator&#39;s actions what would otherwise be a green zone activation may be indicated as a yellow zone activation or a red zone surveillance. As described with reference to FIG. 6, depending upon the surveillance zone active at a given point in time, the type of data and priority of data in the data repository  302  is modified. As well, the operator display may be modified to indicate the threat assessment and/or active zone of surveillance. In addition, actions associated with the surveillance zone are implemented which, for example, includes a warning for a yellow zone activation, and active or passive countermeasures for a red zone activation as shown in step  422 . 
     As would be evident to those skilled in the art, various permutations and modifications to the above method and system may be performed. For example, information regarding a detected vehicle may be obtained from an autonomous sensing on the operator&#39;s vehicle, wireless transponding from surrounding vehicles, or the vehicle&#39;s operating environment itself such as in the case of an intelligent intersection having capability to detect and monitor vehicles within its field-of-view and transmit information regarding such vehicles to vehicles in the area having the capability to receive such information. 
     From the foregoing, it will be seen that there has been brought to the art a new and improved method and apparatus for pre-crash threat assessment using spheroidal partitioning. While the invention has been described in connection with one or more embodiments, it should be understood that the invention is not limited to those embodiments. On the contrary, the invention covers all alternatives, modifications, and equivalents as may be included within the spirit and scope of the appended claims.