Abstract:
A navigation system and a wireless communication device are installed on an automobile. The navigation system determines the state vector of the automobile. The navigated state vector is periodically transmitted by the wireless communication device for use by other vehicles. The wireless communication device also receives state vectors transmitted from neighboring vehicles. The received state vectors are compared with the automobile&#39;s current state vector by a processor. The processor drives a display that displays the relative position of the neighboring vehicles. The processor also determines the likelihood of collision with another vehicle. The processor issues display or audio cues to alert the driver. The processor may also send brake or steering commands when a driving correction should be made.

Description:
BACKGROUND 
       [0001]    1. Field 
         [0002]    The invention relates to automobile safety. More particularly, the invention relates to automobile safety systems for collision avoidance. 
         [0003]    2. Background 
         [0004]    Navigation systems have become smaller, more accurate and more affordable in recent years. The global positioning system (GPS) is a satellite based navigation system having a constellation of satellites that broadcast precise timing signals. The timing signals can be received and processed to determine the precise time and geodetic position and velocity of the receiver. An inertial navigation system (INS) is a navigation system having angular sensors and accelerometers. The angular sensors measure angular position, angular rates, or both. The accelerometers measure accelerations that are integrated over time to determine changes in velocity and position. 
         [0005]    A GPS receiver, an INS, or both may be used in moving vehicles to estimate a vehicle state. The vehicle state can be expressed in the form of a vector. The state vector is a vector having one or more elements that describe the vehicle state. The state vector could include for example the vehicle&#39;s position (i.e. latitude, longitude, and elevation), velocity, acceleration, and angular position (i.e. pitch, roll, and heading). Vehicles having both a GPS receiver and an INS frequently use a Kalman filter algorithm or other state estimation algorithm to blend the GPS and INS state vectors to produce a very accurate blended state vector. The advent of GPS chip technologies and inertial Microelectromechanical system (MEMS) technologies make many GPS receivers and INSs small and affordable. 
         [0006]    Wireless communications devices have also become smaller and more affordable. Promulgation of wireless standards such as IEEE 802.11 has enabled manufacturers to produce wireless communication devices that are interoperable with a variety of other types of wireless communication devices. These inexpensive wireless communication devices are frequently used to transmit and receive data through wireless networks. The popularity of these devices has led to market forces that have driven manufacturers to produce smaller and more affordable wireless communication devices. 
         [0007]    Automobile collisions kill approximately 1.2 million people each year. Many of these collisions are a result of a lack of situational awareness by the driver. Poor situational awareness may be caused weather conditions such as fog, mirror blind spots or physical obstructions. Driver distraction and inattentiveness may also contribute to lack of situational awareness. Automobile safety systems such as mirrors, turn signals and lights provide the driver with enhanced awareness but are ineffective in many situations. This results in a significant number of automobile collision casualties. 
         [0008]    The large number of automobile collision casualties demonstrates that there is a need for better safety systems that reduce the number and severity of automobile collisions. Applicant&#39;s invention addresses this need. 
       SUMMARY 
       [0009]    A navigation system and wireless communication device are installed in an automobile. The navigation system determines the automobile state and outputs the state vector. The wireless communication device transmits the state vector for use by neighboring automobiles. The wireless communication device also receives the state vectors of neighboring vehicles. A processor compares the automobile&#39;s state vector with the state vectors of neighboring vehicles. The processor may generate situational awareness symbology for a display, provide audio commands for audio cuing device; or issue commands to the vehicle braking or steering systems. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    Claimed subject matter is particularly pointed out and distinctly claimed in the concluding portion of the specification. However, such subject matter may be understood by reference to the following detailed description when read with the accompanying drawings in which: 
           [0011]      FIG. 1  is a block diagram showing an embodiment of the present invention. 
           [0012]      FIG. 2  is a block diagram showing an embodiment of the processor shown in  FIG. 1 . 
           [0013]      FIG. 3  shows the contents of an exemplary state vector processed in the processor in  FIG. 2 . 
           [0014]      FIG. 4  shows a first exemplary driver display page for the display shown in  FIG. 1 . 
           [0015]      FIG. 5  shows a second exemplary driver display page for the display shown in  FIG. 1 . 
           [0016]      FIG. 6  shows a third exemplary driver display page for the display shown in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    Methods and apparatus that implement the embodiments of the various features of the disclosure will now be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate embodiments of the invention and not to limit the scope of the invention. Reference in the specification to “one embodiment” or “an embodiment” is intended to indicate that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least an embodiment of the invention. The appearances of the phrase “in one embodiment” or “an embodiment” in various places in the specification are not necessarily all referring to the same embodiment. Throughout the drawings, reference numbers are re-used to indicate correspondence between referenced elements. In addition, the first digit of each reference number indicates the figure in which the element first appears. 
         [0018]      FIG. 1  shows a block diagram of an embodiment of the automobile collision avoidance system (ACAS). The ACAS is controlled by a processor  102 . The processor  102  is connected with an inertial system (INS)  104  and a global positioning system (GPS) receiver  106  that generate navigation information. The processor  102  is also connected with a wireless communication device  108  that transmits and receives digital data. The processor  102  drives a display  110  and an audio cuing device  112  for alerting a driver. The processor  102  provides control inputs to the automobile&#39;s braking and steering systems (not shown). 
         [0019]    This embodiment includes complementary navigation systems, the INS  104  and the GPS receiver  106 . Alternate, embodiments may feature an integrated GPS and INS navigation system or other navigation system. The use of only an INS  104  or only a GPS receiver  106  as the sole source of navigation information is also contemplated. 
         [0020]    A display  110  and an audio cuing device  112  provide both visual and audio situational awareness information to a driver. Alternate embodiments may feature only a display  110  or only an audio cuing device  112  as the sole source of ACAS information for the driver. Embodiments that interact directly with the braking and steering systems that provide no ACAS information to the driver are also contemplated. 
         [0021]    The INS  104  supplies the processor  102  with navigation information derived from accelerometers and angular position or angular rate sensors. The processor  102  may also provide the INS  104  with initial position data or periodic position updates that allow the INS  104  to correct drift errors, misalignment errors or other errors. 
         [0022]    The INS  104  may be a standard gimbal or strapdown INS having one or more gyroscopes and substantially orthogonally mounted accelerometers. Alternatively, the INS  104  may have accelerometers and microelectromechanical systems (MEMS) that estimate angular position or angular rates. An INS  104  having a gyroscope for detecting automobile heading and a speed sensor is also contemplated. 
         [0023]    The GPS receiver  106  supplies the processor  102  with navigation information derived from timing signal received from the GPS satellite constellation. The processor  102  may provide the GPS receiver  106  with position data to allow the GPS receiver  106  to quickly reacquire the timing signals if the timing signals are temporarily unavailable. GPS timing signal may be unavailable for a variety of reasons, for example, antenna shadowing as a result of driving through a tunnel or an indoor parking garage. The GPS receiver  106  may also have a radio receiver for receiving differential corrections that make the GPS navigation information even more accurate. 
         [0024]    The INS  104  and the GPS receiver  106  are complementary navigation systems. The INS  104  is very responsive to changes in the trajectory of the automobile. A steering or braking input is sensed very quickly at the accelerometers and the angular position sensors. INS  104  position and velocity estimates, however, are derived by integrating accelerometer measurements and errors in the estimates accumulate over time. The GPS receiver  106  is not generally as responsive to changes in automobile trajectory but continually estimates position very accurately. The use of both the INS  104  and the GPS receiver  106  allows the processor  102  to estimate the automobile&#39;s state more accurately than with a single navigation system. 
         [0025]    The wireless communication device  108  receives the automobile&#39;s navigated state vector from the processor  102 . The wireless communication  108  device broadcasts this state vector for use by neighboring automobiles. The wireless communication device  108  also receives the state vectors from neighboring automobiles. The received state vectors from the neighboring automobiles are sent to the processor  102  for further processing. 
         [0026]    The wireless communication device  108  may be part of a local area wireless network such as an IEEE 802.11 network. The local area network may be a mesh network, ad-hoc network, contention access network or any other type of network. The use of a device that is mesh network enabled according to a widely accepted standard such as 802.11(s) may be a good choice for a wireless communication device  108 . The wireless communication device  108  may also feature a transmitter with low broadcast power to allow automobiles in the area to receive the broadcast signal. The broadcast of state vectors over a broad area network or the internet is also contemplated. 
         [0027]    The display  110  and the audio cuing device  112  are features that provide the driver with situational awareness. The processor  102  sends commands to the display  110  and the cuing device  112  that alert the driver to hazards. The display  110  may for example show the relative positions and velocities of neighboring vehicles. The display  110  may also warn the driver to slow down or apply the brakes immediately. The audio cuing device  112  may give aural warnings such as “STOP” or “CAUTION VEHICLE APPROACHING”. 
         [0028]    The braking and steering systems (not shown) may also be commanded by the processor  102 . The processor  102  may command that the brakes be applied to prevent collision with a vehicle ahead or may provide a steering input to prevent the driver from colliding with a vehicle. The processor  102  may also issue braking or steering commands to minimize the damage resulting from a collision. 
         [0029]      FIG. 2  shows the processor  102  of  FIG. 1 . The processor  102  receives INS state information from the INS. The INS state processing module  202  uses the INS information to produce an INS state vector. The processor  102  also receives GPS information from the GPS receiver. The GPS state processing module  204  uses the GPS information to produce a GPS state vector. The blended state processing module  206  receives the INS state vector from the INS state processing module  204  and the GPS state vector from the GPS state processing module  204  and produces a blended state vector. 
         [0030]    The state vectors from the INS state processing module  202 , the GPS state processing module  204  and the blended state processing module  206  are sent to a state vector module  208  that selects an appropriate state vector. The selected state vector is sent to a transmit and receive data processing module  210  that pre-processes data bound for the wireless communication device. The selected state vector is also sent to the state vector trajectory processing module  212 . The transmit and receive data processing module  210  also processes state vectors received from the wireless communication device and forwards to the state vectors to the processing module  212 . 
         [0031]    The state vector processing module generates display and audio information for the display and audio processing module  214 . The display and audio processing module  214  generates display and audio cue commands for driving the display and the audio cuing device. 
         [0032]    The INS state processing module  202  processes the inertial information and generates an INS state vector. To generate the INS state vector the processor  102  may perform time interpolation. The INS state processing module  202  may also model errors over time in the INS using GPS or blended state information. The INS state processing module  202  may also provide the INS with alignment information and initial position information. The INS state processing module  202  may also monitor the INS for failures or poor performance. The INS state processing module  202  may assign a figure of merit or other indicia of accuracy to the INS state vector. 
         [0033]    The GPS state processing module  204  processes the GPS receiver information and generates a GPS state vector. To generate the GPS state vector the processor  102  may perform time interpolation. The GPS state processing module  204  may monitor the GPS receiver for satellite outages. The GPS state processing module  204  may provide position data to the GPS receiver for acquiring or reacquiring satellite timing signals. The GPS state processing module  204  may monitor the GPS receiver for failures or poor performance. 
         [0034]    The state vector module  208  chooses an appropriate state vector and may assign indicia of quality to the state vector. The state vector module  208  may monitor the blended, GPS and INS state vector for quality. The state vectors module  208  may nominally choose the blended state vector but may select the GPS or INS state vector if the state vector module  208  determines the GPS or INS state vector is more appropriate. For example the GPS state vector may be the most appropriate state vector if one of the INS accelerometers is failing and there is little confidence in the information received from the INS and therefore the INS state vector or the blended state vector. 
         [0035]    The transmit and receive data processing module  210  may receive the most appropriate state vector from the state vector module  208  at regular intervals. The transmit and receive data processing module  210  may format and send the state vector to the wireless communication device. The transmit and receive data processing module  210  may also receive data from the wireless communication device. The data may be unpacked and formatted into state vectors for further processing by the state vector trajectory processing module  212 . 
         [0036]    The state vector trajectory processing module  212  receives the automobile state vector from the state vector module  208  as well as other vehicles state vectors from the transmit and receive data processing module  210 . The state vector trajectory processing module  212  may use the information in the state vectors to predict the position of the automobile and other vehicles over a time interval, for example five seconds. The projected automobile position and other vehicle positions may be checked to see if a collision event is likely. 
         [0037]    The trajectory analysis may also include analysis of vehicle trajectory histories. Historical trajectory analysis may be useful, for example, to determine if the automobile and other vehicles are traveling in the same lane of a multiple lane highway. The trajectory analysis may also use driver driving models to allow the state vector trajectory processing module  212  to determine when and if to issue driver warnings. The trajectory analysis may also take into account any self reported accuracy indicators in the state vectors received from other vehicles. 
         [0038]    The state vector trajectory processing module  212  may also generate braking or steering commands to send to the automobile&#39;s braking and steering systems for preventing a collision or minimizing the damage from a collision. 
         [0039]    The state vector trajectory processing module  212  sends information to the display and audio processing module  214 . The display and audio processing module  214  formats the information for display. The display and audio processing module  214  generates symbology for the display and the audio cues for the audio cuing device. 
         [0040]      FIG. 3  shows an exemplary state vector  300  processed by the processor  102 . The state vector includes the time  302  the state vector was estimated. The state vector also includes the three dimensional position of the automobile in earth centered earth fixed coordinates, shown as position X  304 , position Y  306 , and position Z  308 . The state vector also includes the three dimensional velocity of the automobile in earth centered earth fixed coordinates, shown as velocity X  310 , velocity Y  312 , and velocity Z  314 . The state vector also includes the three dimensional acceleration of the automobile in earth centered earth fixed coordinates, shown as acceleration X  316 , acceleration Y  318 , and acceleration Z  320 . 
         [0041]    The state vector shown is exemplary. The automobile state vector may have more or less elements describing the state of the vehicle. For example the state vector may contain entries that describe the angular position, the angular rates, and the angular accelerations. The state vector may be described using any coordinate system or any type of units. The state vector may also contain information about the vehicle such as its weight, stopping distance, its size, its fuel state etc. 
         [0042]    Information packed in the state vector may be of value in collision avoidance trajectory analysis or may be useful for generating and displaying more accurate display symbology for the driver. For example, the automobile may receive a state vector from a neighboring vehicle that identifies the vehicle as an eighteen wheel truck with a ten ton load. Such information may be important for trajectory analysis and for providing accurate and informative display symbology. 
         [0043]      FIG. 4  shows a first exemplary display page that may be shown on the display  110 . An annunciation line  402  displays “NO LANE CHANGE” to the driver indicating that a lane change would be unsafe. Road display symbology  404  shows a two lane highway with cars traveling in the same direction. Road display symbology  404  may be generated based on map data stored in a database or determined from state vector data from the automobile and received state vectors from surrounding vehicles. 
         [0044]    An automobile symbol  406  has a dark outline indicating that this symbol represents the driver&#39;s automobile. A “55 numeric in the automobile symbol  506  alerts the driver of his speed. An arrow extending from the automobile symbol  506  informs the driver of his direction of travel. A vehicle symbol  408  shows that another vehicle is at the five o&#39;clock position relative to the automobile. The numeric  60  inside the vehicle symbol  408  alerts the driver that the vehicle is traveling at sixty miles an hour. 
         [0045]    From the display, it is evident that the vehicle may pass by the automobile shortly. Accordingly, the annunciation line  402  alerts the driver that it&#39;s unsafe to change lines at this time. This display is particularly valuable when the vehicle represented by the vehicle symbol  408  is in the automobile&#39;s blind spot. A countdown timer  410  indicates that 5.3 seconds is the expected amount of time that must elapse before it is safe for the driver to make a lane change. In this case 5.3 seconds may indicate the amount of time required for the vehicle to overtake the automobile clearing the right lane for a safe lane change. 
         [0046]      FIG. 5  shows a second exemplary display page that may be shown on the display  110 . The annunciation line  402  displays “REDUCE SPEED SLOW VEHICLES AHEAD”. The road display  404  shows a two lane highway with cars traveling in the same direction. The automobile symbol  502  is dark to alert the driver that the symbol represents the driver&#39;s automobile. The symbol shows that the automobile is traveling at 70 MPH. An X symbol  504  placed next to the automobile symbol  502  alerts the driver that changing lanes is not recommended. 
         [0047]    A first vehicle symbol  506  shows that a first vehicle is ahead of the automobile, in the other lane, and is traveling at 35 miles an hour. A second vehicle symbol  508  shows a second vehicle traveling in the same lane as the automobile at 40 MPH. A countdown timer  510  alerts the driver that in 4.2 seconds the driver&#39;s automobile will collide with second Vehicle  508  if the driver does not adjust his speed. 
         [0048]    This view might be particularly helpful in fog. The driver is alerted that there is slow traffic ahead and may begin to reduce the speed of the automobile. Anticipating the required speed reduction decreases the chance of collision due to distractions or inattentiveness. 
         [0049]      FIG. 6  shows a third exemplary display page that may be shown on the display  110 . The annunciation line  402  alerts the driver to remain stopped. Road display symbology  502  shows that the automobile is stopped at an intersection. The automobile symbology  504  has a dark outline to indicate to the driver that the symbol represents the driver&#39;s automobile. A first vehicle symbol  506  shows that a first vehicle is approaching the intersection from the left side at 20 MPH. A second vehicle symbol  508  shows that a second vehicle is also approaching the intersection from the right side at 25 MPH. A third vehicle symbol  510  shows that a third vehicle is stopped behind the driver&#39;s automobile. 
         [0050]    A first countdown timer  512  shows that in 1.4 seconds the first vehicle is expected to finish crossing the intersection. A second countdown timer  514  shows that in 1.2 seconds the second vehicle is expected to finish crossing the intersection. The second countdown timer also shows a 2.5 second and 4.1 second entries with arrows indicating that a fourth and fifth vehicle not shown on the display  110  are expected to finish crossing the intersection. 
         [0051]    The driver seeing this display  110  realizes that it will be about 4.1 seconds before it is safe to cross the intersection. This view is particularly useful if the corners adjacent to the driver&#39;s automobile are obstructed by buildings or trees. The driver does not have to dangerously “inch up” into the intersection to see the first and second vehicles. 
         [0052]    The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. 
         [0053]    The invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive and the scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.