Abstract:
A driver advisory system for previewing the local traffic conditions on a highway is described. Apparatus according to an embodiment of the present invention includes an advisory system that transmits information regarding the status of the host vehicle to drivers of other vehicles, in particular when the status of the host vehicle presents a hazardous condition to other vehicles. The advisory system may also receive information from other vehicles, and provide an alert to the driver of the host vehicle if a hazardous condition exists.

Description:
REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority from and is a continuation-in-part of U.S. patent application Ser. No. 11/548,419, filed Oct. 11, 2006, which claims priority from U.S. Provisional Application Ser. No. 60/725,967 filed Oct. 12, 2005, both of which are incorporated herein by reference in their entirety. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The invention relates to a driver advisory system for use in a host vehicle on a highway.  
       BACKGROUND OF THE INVENTION  
       [0003]     Highway driving has unique characteristics compared to other road types. Shifting to PARK mode is a typical event near an arterial road, side street or parking lot, but on a highway it is an important data element that can be shared for the benefit of the driving public. The same is true with parameters such as lower vehicle speeds, a passenger opening a door, or a driver getting out of their seat to leave a vehicle.  
         [0004]     Information concerning the status of a vehicle on a highway is currently provided by variable advisory message signs and wide-area radio frequency broadcasts, but these methods provide incomplete information that can be inconvenient to access. Advisory message signs are typically constructed along only urban highways, are usually situated at distant intervals, and are often difficult to read. Wide-area broadcasts that address the status of a vehicle on a highway have issues involving infrastructure coverage and timeliness of their reporting because the broadcasts are supported by detection methods that are limited in nature. Data collection and dissemination regarding the status of a vehicle on a highway currently focuses on the aftereffect that a vehicle has on surrounding traffic patterns. The entry and exit of occupants and the operational status of the vehicle are aspects that are not satisfactorily addressed by current systems.  
         [0005]     In Japanese Patent laid-open Application No. 2004-78562, a communication system is disclosed for transmitting information regarding the driver&#39;s status to a remote vehicle. This patent application, however, does not disclose a system for providing an advisory message to other vehicles regarding the location of the occupants of a vehicle on a highway. Further, it does not disclose a system for providing information regarding the relative operational characteristics of a car in the same said location, and does not provide an advisory message that focuses on vehicle operations that are outside the scope of typical highway driving.  
       SUMMARY OF THE INVENTION  
       [0006]     The present invention discloses short-range communications of less than 1000 meters to provide highway drivers with a preview of their local environment. A driver advisory system is provided for use in a host vehicle. The advisory system includes a sensor, a processor, and a communication unit. The sensor monitors the conditions of the host vehicle relevant to highway travel. The sensor provides an output quantifying the highway travel status of the host vehicle. The processor receives the output provided by the sensor and can calculate a risk factor as a function of the output provided by the sensor. The processor can also provide an output signal having information concerning the status of the host vehicle and its occupants in response to the risk factor exceeding a predetermined threshold value. The communication unit receives the output signal from the processor and transmits the information for retrieval by other vehicles in the vicinity of the host vehicle. The communication unit can also receive similar information from other vehicles and sends it to a second processor. The second processor then determines if a hazardous situation in the vicinity should be reported to the driver. 
     
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0007]      FIG. 1  is a schematic of an advisory system according to an embodiment of the invention;  
         [0008]      FIG. 2  is a schematic that shows how transmit power and Received Signal Strength Indication (RSSI) can be used to determine vehicle proximity.  
         [0009]      FIG. 3  is a flowchart describing a mode of operation of an advisory system according to an embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0010]     This invention relates to a driver advisory system for use in a host vehicle and for providing an alert to the drivers of other vehicles traveling on a highway in the vicinity of the host vehicle. More specifically, the system relates to a driver advisory system that provides an alert to the drivers of other vehicles regarding the status of the host vehicle when the host vehicle is performing non-standard operations on a highway. The advisory system detects highway-related conditions of the host vehicle and its drivers and passengers. The advisory system then broadcasts or transmits a message about these conditions to vehicles in the vicinity of the host vehicle. The advisory system also provides a vehicle description, the heading of the host vehicle, and its position information.  
         [0011]     The advisory system is generally indicated in  FIG. 1 . The advisory system  10  is associated with a host vehicle (host vehicle A), and includes at least one sensor  14  for sensing a vehicle parameter  16  of the host vehicle A. In this example, a plurality of sensors  14  are used for sensing vehicle parameters  16  relevant to highway travel illustratively including vehicle speed and stability thresholds, directional heading (compass), yaw rate, transmit power, RSSI (Received Signal Strength Indication), airbag deployment status, transmission mode (PRNDL), emergency brake applied, hazard light and head/tail/parking lights status, seat occupancy, door open/close status, vision data, radar data, vehicle make/model/color, vehicle location, and highway identification. Sensors  14  may be any type of suitable sensor known by those of ordinary skill in the art, such as switch-based sensors, force/weight sensors, inductive sensors, vision sensors, radar sensors, capacitive sensors, and sensors that detect digital memory. Each sensor  14  provides a sensor output related to a vehicle parameter  16 .  
         [0012]     A first processor  20  receives the sensor outputs provided by the sensors  14 . The first processor  20  calculates a risk factor as a function of the sensor outputs, and provides an output signal in response to the risk factor exceeding a predetermined threshold value. The output signal includes information concerning the highway status of the host vehicle.  
         [0013]     A communication unit  18  receives the output signal from the first processor  20 . The communication unit  18  transmits an advisory message (shown as arrow B) for retrieval by other vehicles in the vicinity of the host vehicle. In this example, the communication unit  18  is a dedicated short-range communication device having a receiver and transmitter. An antenna  24  can be mounted on the vehicle. The communication unit  18  can, for example, communicate via a radio frequency, low or high band frequencies, Zigbee, or 802.11-based protocol. The advisory message can either be broadcast a single time, for example if the host vehicle A is traveling at a low speed, or at intervals when a vehicle parameter  16  indicates a hazardous status, such as when the host vehicle A is in PARK or a door is open.  
         [0014]     The advisory system  10  may also receive advisory messages (shown as arrow A) transmitted from a second vehicle (host vehicle B) in the vicinity of host vehicle A. Specifically, the communication unit  18  can receive messages transmitted from vehicle B regarding the status of host vehicle B, its occupants, the highway position and heading.  
         [0015]     Upon receiving messages transmitted from vehicle B, the communication unit  18  can provide a signal to a second processor  22 . With the outputs from vehicle sensors  14  and the signal from communication unit  18 , the second processor  22  continuously calculates the distance and position of the host vehicle A relative to the vehicle B. This function, and others, may alternatively be performed by a single processor.  
         [0016]     The distance and position of vehicle A relative to vehicle B can be determined using historical data, and may include vehicle speed, compass heading, yaw rate, transmit power, RSSI, the time/location of vehicles passing on the same side and on the opposite side of the highway, and the temporary ID of the vehicle. This historical data can also be periodically sent out from all vehicles. To optimize channel usage and to avoid unnecessary processing, a host vehicle may select appropriate data for transmission.  
         [0017]     The second processor  22  of host vehicle A can provide an alert signal regarding the highway status of vehicle B and its occupants. A human machine interface (HMI)  12  receives the alert signal and provides information to a driver and/or passenger of host vehicle A regarding the distance and position of vehicle B relative to the vehicle A. The HMI  12  also provides an advisory message to the driver regarding the highway status of vehicle B and its occupants.  
         [0018]     The second processor  22  can also initiate a rebroadcast of the information received from vehicle B, for example in cases when vehicle A is traveling on the opposite side of the highway relative to vehicle B. The number of rebroadcasts may be limited to a number and interval that is sufficient for informing vehicles that are approaching vehicle B, without flooding the channel with repetitive advisory messages from many vehicles. The second processor  22  can be operable to identify if other vehicles have already rebroadcast the advisory message from vehicle B via information provided within the contents of the advisory message. If there is no evidence of having received a rebroadcast of the advisory message from the vehicle B, the second processor initiates a rebroadcast once an appropriate distance is established between vehicles A and B, and when the original advisory message from vehicle B is no longer detected by vehicle A.  
         [0019]     It can be determined if the host vehicle is approaching a vehicle that is transmitting information by monitoring the Received Signal Strength Indication (RSSI). A vehicle passing the host vehicle can also be detected in this manner.  
         [0020]      FIG. 2  illustrates a technique that permits vehicles to determine the proximity of other transmitting vehicles through the RSSI. Such proximity information allows the receiving vehicle to determine whether or not they are on the same highway as the sending vehicle.  
         [0021]     Once the driver advisory system  10  determines that the host vehicle A is on a highway through a navigation system or another method, the communication unit  18  in vehicle A begins transmitting a periodic signal  30 . This proximity signal  30  is based on a typical or known width of the highway and also includes information concerning the power that the signal is being transmitted. A driver advisory system  10 ′ in a vehicle B traveling in the vicinity of the host vehicle A can determine if it has received a signal with a received signal strength indication (RSSI) that applies to the typical width of the highway the vehicle B is traveling. By first measuring the received signal strength, then comparing it to the power at which the signal is transmitted and factoring in the typical width of the highway, the driver advisory system  10 ′ of vehicle B can determine the proximity of vehicle A and the likelihood of being on the same highway.  
         [0022]     For example, the graph in  FIG. 2  represents an event where vehicle B approaches and passes vehicle A which is standing stationary on the same side of a highway. Vehicles A and B in  FIG. 2  are test vehicles equipped with GPS devices which allow the distance between the vehicles to be calculated as indicated by the Vehicle-to-Vehicle Distance plot. The Vehicle-to-Vehicle Distance plot corresponds directly with the RSSI plot also shown on the graph. The fact that test vehicle A is stationary allows the typical RSSI pattern to be plotted about 400 meters before and 400 meters after the stationary position of vehicle A. As vehicle B approaches vehicle A, the periodic signal  30  transmitted by the driver advisory system  10  in vehicle A is received by the driver advisory system  10 ′ of vehicle B.  
         [0023]     As explained above, the second microprocessor  22 ′ of system  10 ′ determines whether or not vehicles A and B come in close proximity of each other, as indicated by the smallest circled area in the upper portion of  FIG. 2 . This smallest circled area corresponds directly with the circled peak of the RSSI plot in the lower portion of the figure. If processor  22 ′ detects RSSI values that reach the circled peak level, system  10 ′ can determine that vehicle B is traveling on the same highway as vehicle A.  
         [0024]     As for the Received Packet Plot in  FIG. 2 , a “packet” refers to a collection of data elements that can include data on the time of transmission, packet ID, vehicle position in latitude/longitude coordinates, vehicle speed and stability thresholds, yaw rate, transmit power, airbag deployment status, transmission mode (PRNDL), emergency brake applied, hazard light and head/tail/parking lights status, seat occupancy, door open/close status, vision data, radar data, vehicle make/model/color and combinations thereof. In addition, the second processor  22 ′ can determine whether or not an advisory should be submitted to the HMI  12 ′ for communication to an occupant of vehicle B.  
         [0025]     Hence, by transmitting data that includes the power at which the data is being transmitted, other receiving vehicles can monitor the signal strength received so as to calculate the proximity of the transmitting vehicle and determine if they are on the same highway. This signal can also be used on arterial roads for similar locating purposes.  
         [0026]     The detection of a host vehicle A entrance onto a highway can also be aided by monitoring the history of speed, compass heading and/or yaw rate of the host vehicle. Another method of determining that a vehicle A sending information is on a highway includes estimating the highway path using data collected from other vehicles.  
         [0027]      FIG. 3  shows a flowchart for a mode of operation of system  10  in  FIG. 1 . In this example, at step  100  the advisory system within a host vehicle continuously monitors all incoming messages from other systems in the vicinity of the vehicle. Information relating to at least a second vehicle in the vicinity of the host vehicle is stored in a table at step  110 . The system determines if any of the incoming messages are advisory messages provided by a second vehicle at step  120 , and if the advisory message is not a highway local preview message, the system continues to review incoming messages. If the message is a highway local preview message, then the system checks the current location of the vehicles and monitors the RSSI of the second vehicle at step  130 . If the host vehicle is approaching the second vehicle on the same highway and in the same direction of travel, then the system provides an advisory alert to the driver of the host vehicle relating to the location and status of the second vehicle (step  150 ). The system checks the advisory message contents to determine if the advisory message is appropriate for rebroadcast at step  160 . If the advisory message is appropriate for rebroadcast, the system waits until a threshold range is reached and the applicable advisory message is no longer being received, then the system rebroadcasts the advisory message at step  170 .  
         [0028]     The invention has been described in an illustrative manner. It is, therefore, to be understood that the terminology used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the invention are possible in light of the above definition. Thus within the scope of the appended claims, the invention may be practiced other than as specifically described.  
         [0029]     The invention is not restricted to the illustrative examples described above Examples are not intended as limitations on the scope of the invention. Methods, apparatus, electrical circuits, compositions, and the like described herein are exemplary and not intended as limitations on the scope of the invention. Changes therein and other uses will occur to those skilled in the art. The scope of the invention is defined by the scope of the claims.