Abstract:
A road hazard warning system provides a warning to a motorist driving a vehicle of a stationary or moving hazard. A warning system includes a transmitter located near the road hazard that generates a radio frequency (RF) warning signal. A receiver is located in the vehicle and receives the RF warning signal. A receiver is located in the vehicle and receives the RF warning signal. The receiver is preferably integrated with an electronic device associated with the vehicle. The electronic device is at least one of a vehicle radio system, a tape player, a compact disc player, a television, an in-car computer, a video game, a telephone, and a global positioning system. The electronic device generates a warning output signal to a speaker or a display when the RF warning signal is detected by the receiver. A vehicle electronics interface is connected to the electronic device and provides a vehicle speed signal to the electronic device. The RF warning system contains data specifying a localized temporary speed limit. The electronic device compares the localized temporary speed limit with the vehicle speed signal and generates a second warning output signal with the vehicle speed signal and generates a second warning output signal if the vehicle speed exceeds the temporary speed limit. A vehicle speed controller is connected to the electronic device and reduces the vehicle speed if the vehicle speed exceeds the localized temporary speed limit.

Description:
TECHNICAL FIELD 
     This invention relates to electronic devices for identifying a hazardous situation for a vehicle and, more particularly, to electronic warning devices used to alert a motorist to hazardous situations such as construction zones, school zones, accident sites, and emergency vehicles. 
     BACKGROUND OF THE INVENTION 
     There are many instances when emergency vehicles, such as police cars, ambulances, and fire trucks use sirens, beacons, and/or flashing lights to alert motorists and pedestrians to yield. Other vehicles such as tow trucks, delivery vehicles, school buses, and utility repair vehicles may also use alarms and/or flashing lights when reversing, obstructing traffic, or carrying an oversized load. 
     There are many instances when emergency vehicles fail to adequately warn motorists as to their presence. For example, emergency flashers and beacons are harder to spot during daylight hours than at night. Sirens or other audible warnings are harder to detect when motorists are using the car radio or when local ambient noise is relatively high. If motorists or pedestrians fail to yield right of way, emergency vehicles may become involved in traffic accidents that may result in the loss of life due to inadequate warning of a hazardous situation. Oftentimes, accident victims do not have ample warning of the hazard. 
     Because the population is living longer, the number of senior citizens who drive vehicles will continue to be a growing segment of the population. As people age, their reaction times tend to increase. For senior drivers, the response time required to comprehend the hazardous situation and to react accordingly also increases. Therefore, an earlier warning of a hazardous situation such as an emergency vehicle is desirable. 
     Conventional warning systems also fail to identify the location of the emergency vehicle or hazardous situation relative to the motorist to be warned. Without knowing the direction of approach of an emergency vehicle, it is difficult for a motorist to know how to get out of the way. 
     If delivery trucks, repair vehicles and other less dangerous vehicles begin using loud sirens and flashing lights, the warning effect of sirens and flashing lights will be diminished due to over-use. 
     SUMMARY OF THE INVENTION 
     The present invention discloses a system for providing a warning of a road hazard to a motorist driving a vehicle. The warning system includes a transmitter located near the road hazard that generates a radio frequency (RF) warning signal. A receiver is located in the vehicle and receives the RF warning signal. An electronic device is connected to the receiver and is located in the vehicle. The electronic device generates a warning output signal to an audio or a video output device connected to the electronic device when the RF warning signal is detected by the receiver. The electronic device is at least one of a vehicle radio system, a tape player, a compact disc player, a television, an in-car computer, a video game, a telephone, or a global positioning system. 
     In other features, the receiver and electronic device form an integrated circuit. The electronic device includes a processor, an input/output (I/O) interface and memory. The I/O interface is connected to a vehicle electronics interface which generates a vehicle speed signal. The RF warning signal contains data specifying a localized temporary speed limit. The processor decodes the localized temporary speed limit from the data. The processor compares the localized temporary speed limit with the vehicle speed signal and generates a second warning output signal to notify the motorist that the vehicle speed exceeds the localized temporary speed limit. 
     In another feature, a vehicle speed controller is connected to the processor. The processor reduces the vehicle speed if the vehicle speed exceeds the localized temporary speed limit. 
     In still other features, a direction indicator is connected to the processor and generates at least one of an audio signal and a video signal that indicates a location of the road hazard relative to the vehicle. The direction indicator preferably includes a plurality of antennas connected to the receiver and the processor. 
     In yet another feature, of the invention, the RF warning signal specifies one of a plurality of different warning levels. The electronic device outputs a plurality of different output signals based on the warning level received by the receiver and the processor. 
     Still other features, benefits and advantages will be apparent from the specification, the drawings and the claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a functional block diagram of an emergency warning system according to the present invention and including a transmitter associated with a hazardous situation, and a receiver associated with a motorist&#39;s vehicle; 
     FIG. 2 is a functional block diagram of the receiver of FIG. 1 integrated with an existing vehicle electronic device; 
     FIG. 3 is a functional block diagram illustrating a processor, memory and an interface that are associated with the vehicle electronic device of FIG. 2; 
     FIG. 4 is a functional block diagram of a transmitter and a receiver according to one embodiment of the present invention; 
     FIG. 5 illustrates steps for detecting and generating a hazard signal; 
     FIG. 6 illustrates the steps for detecting and generating a speed limit warning from the hazard signal; 
     FIG. 7 illustrates the steps associated with detecting and reducing vehicle speed based on the hazard signal; 
     FIG. 8 illustrates another embodiment of the hazard warning system that identifies the location of a hazardous situation or vehicle relative to the motorist&#39;s vehicle; 
     FIG. 9 illustrates steps associated with generating a visual or audio message indicating the relative location of the emergency vehicle; 
     FIG. 10 illustrates a directional display for identifying the location of the hazardous situation or vehicle relative to the motorist&#39;s vehicle; 
     FIG. 11 illustrates a function block diagram of a transmitter associated with a first global positioning system and a receiver associated with a second global positioning system according to an alternate embodiment of the present invention; 
     FIG. 12 illustrates a display that is associated with the second global positioning system of FIG. 11; and 
     FIG. 13 is a functional block diagram of an alternate receiving unit associated with the motorist&#39;s vehicle. 
    
    
     DETAILED DESCRIPTION 
     With reference to FIG. 1, a hazard warning system  10  is illustrated and includes a transmitter  12  associated with a hazardous situation  14 . The hazardous situation  14  can be moving such as an emergency vehicle, a school bus, a police car, an ambulance, or stationary such as a construction zone, a school zone, an accident site, a delivery vehicle making deliveries, a repair vehicle, etc. 
     The transmitter  12  is connected to a switch  16  which actuates the transmitter  12 . The switch  16  is thrown when the hazardous situation is present, such as when an ambulance is going to an emergency or returning to a hospital. A signal generator  18  is connected to the switch  16 . An antenna  20  transmits signals generated by the transmitter  12 . A power supply (not shown) is also associated with the transmitter  12  and provides power to the transmitter  12 . 
     A receiver  30  is connected to an output device  32  and an antenna  34 . The output device  32  includes an audio output device  52  such as a speaker and/or a visual output device  54  such as a liquid crystal display (LCD), a light-emitting diode (LED), a cathode ray tube (CRT), a lamp, or other suitable visual display devices. The receiver  30  is associated with a vehicle  36  that is operated by a motorist. A hazard signal (identified at  40 ) is transmitted by the transmitter  12  when the switch  16  is actuated. Information is encoded into the hazard signal using the signal generator  18 . For example, the signal generator  18  includes information concerning a localized temporary speed limit. The hazard signal is transmitted by the antenna  20  to the antenna  34  and the receiver  30  associated with the motorist&#39;s vehicle  36  as will be described in further detail below. 
     In use, personnel associated with the hazardous situation  14  toggle the switch  16  which triggers the signal generator  18  and transmitter  12  to output the hazard signal  40 . The transmitter  12  employs suitable signal processing techniques such as amplitude modulation (AM), frequency modulation (FM), pulse width modulation (PWM), spread spectrum (SS), or other suitable signal processing techniques. The transmitter  12  generates the hazard signal  40  and transmits the hazard signal  40  via the antenna  20 . 
     The antenna  34  associated with the motorist&#39;s vehicle  36  receives the hazard signal  40  and outputs the hazard signal to the receiver  30 . The receiver  30  generates an audio warning signal such as a beeping noise and/or a visual signal such as a flashing lamp or LED to alert the motorist. 
     Referring to FIG. 2, one embodiment of the hazard warning system  10  is illustrated. The receiver  30  is integrated with an electronic device  50  such as a radio, tape player, CD player, CB radio, television, video game, in-car computer, GPS, telephone, etc., to reduce costs. The receiver  30  is fabricated on the same circuit board as the electronic device  50  to form an integrated circuit. For example, the electronic device  50  is the car radio and the receiver  30  is fabricated on the same circuit board as the car radio. If the hazard signal  40  is transmitted at a frequency associated with FM or AM broadcasting, or if the signal  40  is generated at a frequency that can be received by an antenna associated with the car radio, the antenna  34  can be omitted and the antenna associated with the electronic device  50  can be used. Alternately, a thin wire located in a windshield of the vehicle or a metallic body panel can be used as an antenna. 
     If the electronic device  50  is a car radio, the visual output device or display  52  is a radio faceplate and the audio output device  52 . is one or more audio speakers. The electronic device  50  and the receiver  30  can be powered by a power supply  56 . As can be appreciated by skilled artisans, by integrating the receiver  30  with the electronic device  50 , duplicate power supplies, antennas, displays and speakers can be eliminated. The electronic device  50  can be connected to other vehicle electronic devices  58  such as an engine control module (ECM) or a data bus for vehicle information systems. 
     Referring now to FIG. 3, the electronic device  50  typically includes an input/output interface (I/O)  60  which is connected to a processor  62  and memory  64 . Memory  64  includes read only memory (ROM) and random access memory (RAM). The processor  62  controls the operation of the electronic device  50 . Preferably, the processor  62  controls the recovery of information contained in the hazard signal and/or the detection of the hazard signal by the receiver  30 . 
     Referring now to FIG. 4, a preferred embodiment of the transmitter  12  and the receiver  30  is illustrated. The transmitter  12  is a frequency modulated transmitter that includes an oscillator  70  that is connected to the signal generator  18  and a modulator  72 . The modulator  72  is connected to a power supply  74  and one or more frequency multipliers  76 . The power supply  74  can be connected to other components of the transmitter  12  if needed. A power amplifier  78  is connected to the frequency multipliers  76  and to an antenna  80 . As can be appreciated, the transmitter  12  illustrated in FIG. 4 performs frequency modulation (FM) for encoding information contained in a signal output by the signal generator  18  in a conventional manner. 
     In use, information is contained in the signal output by the signal generator  18 . The transmitter frequency modulates the signal, amplifies the frequency modulated signal, and outputs the frequency modulated signal (shown at  82 ) via the antenna  80 . 
     The receiver  30  includes an antenna  84  which is coupled to an RF amplifier  90  which amplifies a signal received by the antenna  34  and outputs the signal to a mixer  92 . The mixer  92  mixes the signal received by the RF amplifier with a signal generated by a local oscillator  94 . The signal output by the mixer  92  is input to one or more intermediate frequency (IF) amplifiers  96 . The signal output by the IF amplifier  96  is input to a limiter  98  which outputs a signal having a variable frequency and a relatively constant amplitude. A discriminator  100  translates frequency variations of the signal into an audio signal. An amplifier  102  amplifies the discriminated signal. The signal output by the amplifier  102  can be used to drive a display  52  or a speaker  54 . Because the signal will generally have a high frequency, the display may appear to have a constant “ON” state and the speaker will sound as if a continuous tone is being generated. 
     As can be appreciated, different emergency signals can be generated for different types of hazards. This can be accomplished by varying the frequency of the signal generated by the signal generator when frequency modulation is used. The amplitude of the signal can be varied if amplitude modulation is employed. Pulse width modulation, data encoding or other suitable techniques can be employed. 
     For example, a severe hazard warning signal can be generated for fire, ambulance and police vehicles which may require a prompt response from the motorist. In response to the severe hazard warning, the receiver  30  generates a first type of emergency signal such as triggering a harsh audio warning signal, illuminating a bright lamp, initiating a recorded message, or turning the radio off. A second level emergency warning signal message indicates that school zones, accident scenes and/or construction sites are nearby. The second level hazard warning signal includes turning the volume of the radio down but not off, triggering a medium volume level audio warning signal, flashing a lamp at a medium pace, and/or playing a recorded message. A low level hazard warning is issued by the transmitter  10  for repair or delivery vehicles that are in the vicinity of the motorist&#39;s vehicle. In response to the low level hazard warning signal, the receiver and/or processor triggers a low volume level audio signal, flashes a lamp at a medium pace, or plays a recorded message. 
     Referring now to FIG. 5, operational steps associated with a first hazard warning system are shown. The receiver  30  and/or the receiver  30  in combination with the electronic device  50  or the processor  62  detects the hazard signal at step  110 . At step  112 , the type of emergency is detected if the hazard signal possible contains more than one different type. At step  114 , a warning signal that includes audio and/or visual output is generated based on the type of emergency as previously described above. 
     In FIG. 6, the steps  110 - 114  are performed. In step  116 , a localized temporary speed limit signal is detected from the hazard signal. At step  118 , the speed of the motorist&#39;s vehicle  36  is detected from the vehicle electronics  58 . At step  120 , an additional hazard warning is generated if the speed of the motorist&#39;s vehicle exceeds the localized temporary speed limit contained in the hazard signal. The additional hazard warning can be an alarm, an alphanumeric message output on an LED display, a recorded message, a light or other suitable indicator. 
     In FIG. 7, steps  110 ,  112 ,  114 ,  116 , and  118  from FIG. 6 are performed. At step  124 , the speed of the vehicle is reduced to the localized temporary speed limit by the vehicle&#39;s electronics  58  (through fly-by-wire systems, traction control, anti-lock braking systems (ABS), etc.). 
     Referring now to FIG. 8, a hazard warning system with directional capabilities is illustrated. The receiver  30  is preferably integrated with a radio receiver  142 . The interface  60 , the processor  62  and the memory  64  of the radio receiver  142  are connected to the receiver  30 , the display  52  and one or more speakers  54 . The speakers  54  are preferably the speakers associated with the radio receiver  142 . A plurality of antennas  144 ,  146 , and  148  are located in a spaced relationship and are connected to the receiver  30 . The receiver  30 , the interface  60 , the processor  62 , and the memory  64  perform signal triangulation on the hazard signals received by the antennas  144 ,  146 , and  148  in a conventional manner. As can be appreciated, the location of the transmitter  12  associated with the hazard (such as the emergency vehicle) can be determined relative to the motorist&#39;s vehicle and output via a directional visual display or by an audio message. 
     In FIG. 9, steps  110 ,  112 , and  114  from FIGS. 5-7 are performed. At step  152 , the hazard signal received by the antennas  144 ,  146 , and  148  are triangulated. At step  154 , the visual or audio message is generated to indicate the relative location of the emergency vehicle relative to the motorist&#39;s vehicle. 
     In FIG. 10, a preferred visual display device  52  is illustrated. An arrow  160  identifies hazardous situations in front of the vehicle. An arrow  162  identifies hazardous situations behind the vehicle. Arrows  164  and  166  identify hazardous situations to the left and right of the vehicle, respectively. Other arrows  170  identify directions in between the arrows  160 ,  162 ,  164  and  166 . 
     Referring now to FIG. 11, an alternate hazard warning system  200  for a hazardous situation  202  is illustrated and includes a transmitter  204  that is connected to an antenna  208 . A signal generator  212  is connected to the transmitter  204 . A GPS unit  214  and a local speed signal generator  218  are connected to the signal generator  212 . A switch  220  is connected to the signal generator  212 . 
     A motorist&#39;s vehicle  221  includes an antenna  222  that is coupled to a receiver  224 . A GPS unit  226  is connected to the receiver  224 . An output device  230  is connected to the GPS unit  226 . The output device  230  can be a directional unit illustrated in FIG. 10, a display associated with the GPS unit  226 , or an audio output such as a computerized voice output by a speaker. 
     In use, personnel associated with the hazardous situation  202  toggle the switch  220  to actuate the signal generator  212 . The GPS unit  214  generates longitude and latitude information in a conventional manner. The local speed generator  218  generates a local speed signal if applicable (otherwise only the location information is generated). The signal generator  212  and the transmitter  204  employ suitable signal processing techniques such as those described above to generate a warning a signal  232  that is transmitted via the antenna  208 . The antenna  222  receives RF signals containing the warning signal  232  and outputs the RF signals containing the warning signal to the receiver  224 . The receiver  224  employs signal processing techniques that correspond to those employed by the transmitter  204  to process the information. The receiver  224  recovers the warning signal that contains the longitude and latitude information and the localized speed limit (if applicable) from the warning signal  232 . The recovered information is input to the GPS unit  226 . The GPS unit  226 , in turn, outputs the information to the output device  230  which can be aural and/or visual as previously described. 
     Referring now to FIG. 12, the output device  230  of FIG. 11 preferably includes a visual output device  234  which provides a map  235  of an area surrounding the vehicle  221 . The GPS unit  226  generates a symbol  238  that represents the position of the motorist&#39;s vehicle  221  relative to roads  240  on the map  235 . The GPS unit  226  also generates a first symbol  242  that represents a stationary hazard and a second symbol  246  which identifies a local speed limit in an area surrounding the stationary hazard. The GPS unit  226  generates a third symbol  250  that represents a moving hazard such as an ambulance. The GPS unit  226  preferably employs color, size, and/or flashing symbols to identify the severity of the hazard. Moving symbols represent moving hazards. 
     Referring now to FIG. 13, an alternate embodiment of receiving electronics associated with the motorist&#39;s vehicle  260  is illustrated. The receiving electronics can be substituted for the receiving electronics illustrated in the box identified at  221  in FIG.  11 . The receiving electronics include an antenna  262  that is connected to a receiver  264 . An output of the receiver  264  is connected to an input/output interface  266  which is connected to a processor  268  and memory  270 . A GPS unit  274  is connected to the input/output interface  266 . A visual or audio output device  278  is connected to the input/output interface  266 . Alternately, the output device  278  can be connected to or associated with the GPS unit  274 . 
     In use, the antenna  262  receives RF signals containing the warning signal  232  generated by the transmitter  204  and the antenna  208 . The receiver  264  isolates the warning signal from the RF signals received by the antenna  262  and outputs the warning signal to the input/output interface  266 . The processor  268  and the memory  270  perform suitable signal processing to recover the data contained in the warning signal  232 . The GPS unit  274  provides a signal representing a local position of the motorist&#39;s vehicle  260  to the processor  268  and the memory  270  via the input/output interface  266 . The processor  268  calculates a position of the hazard relative to the motorist&#39;s vehicle and outputs a direction signal to the output device  274 . The direction signal can be a computerized voice output by a speaker, a display such as the display of FIG. 10 or  12 , or other suitable visual or aural output. 
     The warning system according to the invention provides motorists with an improved warning system for hazardous situations. By providing an indication of relative direction, the motorist is more likely to avoid an accident. By providing various different types of warning signals, the motorist knows more about the hazardous situation. By incorporating speed control, vehicle speed in the vicinity of the hazardous situation can be controlled. Other objects, features and advantages will be apparent to skilled artisans. 
     While the invention has been described in its presently preferred embodiments, it will be understood that the invention is capable of certain modification and change without departing from the spirit of the invention as set forth in the appended claims.