Patent Publication Number: US-6339382-B1

Title: Emergency vehicle alert system

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This is a utility application taking priority from provisional application, serial number 60/169,562 filed on Dec. 8, 1999. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to emergency vehicles and more specifically to an emergency vehicle alert system which informs the driver of a motor vehicle that an emergency vehicle is close and its location relative to the motor vehicle. 
     2. Discussion of the Prior Art 
     The major challenge for emergency vehicles is traveling through traffic as quickly and safely as possible to get to its destination. At this point in time, the only way for an emergency vehicle to alert vehicles in its path is through an audible siren and emergency lights. Many times, an emergency vehicle coming from behind a motor vehicle cannot be seen or heard until the emergency vehicle is right on top of the motor vehicle. It takes time for the driver to react and maneuver to a location which does not obstruct the emergency vehicle. A more dangerous situation is an emergency vehicle crossing an intersection. It is very difficult for the drivers of oncoming traffic to see or hear an emergency vehicle “buried” in an intersection. The inability of sirens and emergency lights to fully warn motorists of an emergency vehicle&#39;s presence results in thousands of accidents each year. 
     There have been some proposed solutions to the limitations of sirens and emergency lights. A first solution is the use of optical detectors at an intersection that detect light signals emitted from an approaching emergency vehicle. The optical detector would manipulate the traffic signal for oncoming traffic. The drawback to this device is the lack of warning when the emergency vehicle is coming from behind a motor vehicle. 
     A second solution is the use of a radar detector. Radar detectors would be used to detect a signal transmitted from an emergency vehicle. One drawback is that false triggering may result in motorist turning off the radar detector out of frustration. Further, the location and distance of the emergency vehicle relative to the motor vehicle would not be available. 
     A third solution is transmission of an RF signal from an emergency vehicle. Each motor vehicle would have an RF receiver which would receive the RF signal. The distance of the emergency vehicle from the motor vehicle would be displayed on a plurality of lights. Each light would have a value of a particular distance from the emergency vehicle. However, the location of the emergency vehicle relative to the motor vehicle would not be available. 
     Accordingly, there is a clearly felt need in the art for an emergency vehicle alert system which warns the driver of a motor vehicle that an emergency vehicle is close and its location relative to the motor vehicle. 
     SUMMARY OF THE INVENTION 
     The primary objective of the present invention is to provide an emergency vehicle alert system which warns the driver of a motor vehicle that an emergency vehicle is close and its location relative to the motor vehicle. 
     According to the present invention, an emergency vehicle alert system includes an emergency vehicle unit, a motor vehicle unit and at least three global positioning system (GPS) signals. The emergency vehicle unit includes an emergency GPS antenna, emergency GPS receiver, RF transmitter, emergency RF antenna, and emergency power source. The motor vehicle unit includes a vehicle GPS antenna, vehicle GPS receiver, vehicle RF antenna, RF receiver, microcontroller, warning display, and vehicle power source. 
     The at least three GPS signals are continuously broadcast from a plurality of GPS satellites. The emergency GPS antenna receives signals from the plurality of GPS satellites. The at least three GPS signals are input into the emergency GPS receiver. The emergency GPS receiver triangulates the at least three GPS signals into an emergency location signal string which is described by a particular longitude and latitude. The longitude and latitude information is inputed into the emergency RF transmitter and broadcast through the emergency RF antenna. 
     Each vehicle RF antenna which is within range of the emergency vehicle transmission will receive the emergency vehicle longitude and latitude information. The RF receiver inputs the information and sends the emergency vehicle longitude and latitude information to the microcontroller. The vehicle GPS antenna receives at least three different GPS signals from the plurality of GPS satellites. The at least three different GPS signals are input into the vehicle GPS receiver. The vehicle GPS receiver outputs a vehicle location signal string having longitude, latitude, and heading into the microcontroller. The microcontroller compares the location of the emergency vehicle to the location of the motor vehicle. Preferably, the microcontroller will enable at least one of four indicator lamps which indicate the location of the emergency vehicle relative to the motor vehicle. 
     Accordingly, it is an object of the present invention to provide an emergency vehicle alert system which informs a motor vehicle driver of the location of an emergency vehicle relative to their motor vehicle. 
     It is a further object of the present invention to provide an emergency vehicle alert system which does not require installations at street intersections. 
     Finally, it is another object of the present invention to provide an emergency vehicle alert system which informs a driver when an emergency vehicle is close to their motor vehicle. 
     These and additional objects, advantages, features and benefits of the present invention will become apparent from the following specification. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a block diagram of the emergency vehicle unit in accordance with the present invention. 
     FIG. 2 is a block diagram of the motor vehicle unit in accordance with the present invention. 
     FIG. 3 is a front view of the warning display in accordance with the present invention. 
     FIG. 4 is a first page of a flow chart of the software contained within the microcontroller for determining the position of a motor vehicle relative to an emergency vehicle in accordance with the present invention. 
     FIG. 5 is a second page of a flow chart of the software contained within the microcontroller for determining the position of a motor vehicle relative to an emergency vehicle in accordance with the present invention. 
     FIG. 6 is a third page of a flow chart of the software contained within the microcontroller for determining the position of a motor vehicle relative to an emergency vehicle in accordance with the present invention. 
     FIG. 7 is a fourth page of a flow chart of the software contained within the microcontroller for determining the position of a motor vehicle relative to an emergency vehicle in accordance with the present invention. 
     FIG. 8 is a fifth page of a flow chart of the software contained within the microcontroller for determining the position of a motor vehicle relative to an emergency vehicle in accordance with the present invention. 
     FIG. 9 is a coordinate system for determining the position of a motor vehicle relative to an emergency vehicle in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference now to the drawings, and particularly to FIG. 1, there is shown a block diagram of the emergency vehicle unit  10  of the emergency vehicle alert system. An emergency vehicle alert system includes an emergency vehicle unit  10 , a motor vehicle unit  12  and a plurality of global positioning system (GPS) signals  14 . The emergency vehicle unit  10  includes an emergency GPS antenna  16 , emergency GPS receiver  18 , RF transmitter  20 , emergency RF antenna  22 , and emergency power source  24 . The motor vehicle unit  12  includes a vehicle GPS antenna  28 , vehicle GPS receiver  30 , vehicle RF antenna  32 , RF receiver  34 , microcontroller  36 , warning display  38 , and vehicle power source  40 . The emergency power source  24  supplies electrical power to the electronic components in the emergency vehicle unit  10 . The vehicle power source  40  supplies electrical power to the electronic components in the motor vehicle unit  12 . 
     The plurality of GPS signals  14  are continuously broadcast from the plurality of GPS satellites  100 . The emergency GPS antenna  16  receives at least three GPS signals  14  from the plurality of GPS satellites  100 . The at least three GPS signals  14  are input into the emergency GPS receiver  18 . The emergency GPS receiver  18  triangulates the plurality of GPS signals  14  into an emergency location signal string  15  which is described by a particular longitude and latitude. The emergency location signal string  15  is inputed into the RF transmitter  20  and then transmitted through the emergency RF antenna  22 . A Motorola GT Plus Oncore is preferably utilized for the emergency GPS receiver  18  and a Motorola Oncore Active GPS Antenna is preferably utilized for the emergency GPS antenna  16 . Any RF transmitter capable of receiving digital data and transforming thereof into an analog equivalent for RF transmission may be used for the RF transmitter  20 . 
     Each motor vehicle unit  12  which is within range of the emergency vehicle transmission will receive the emergency location signal string  15  through the vehicle RF Antenna  32 . The RF receiver  34  must be able to take the analog signal from the vehicle RF antenna  32  and transform thereof back into the original digital data. The RF receiver  34  inputs the emergency location signal string  15  and sends thereof to the microcontroller  36 . The vehicle GPS antenna  28  receives at least three different GPS signals  14  from the plurality of GPS satellites  100 . The at least three different GPS signals  14  are input by the vehicle GPS receiver  30 . The vehicle GPS receiver  30  outputs a motor vehicle location signal string  42  to the microcontroller  36 . The microcontroller  36  stores all the signal strings in the memory  26 . 
     FIG. 3 discloses a front view of the warning display  38  of the motor vehicle unit  12  which alerts a driver that an emergency vehicle is close. The warning display  38  preferably includes a front indicator lamp  44 , a rear indicator lamp  46 , a left indicator lamp  48 , a right indicator lamp  50 , and a no emergency vehicle indicator lamp  52 . The indicator lamps may be LEDs or any other suitable light emitting device. 
     FIGS. 4-8 disclose a flow chart of the software contained within the microcontroller for determining the position of a motor vehicle relative to an emergency vehicle. Both the emergency vehicle and motor vehicle location signals are defined by a string of data. The string of data may comprise header data or the start of the position string, position data, heading data, velocity data, and checksum data. The checksum data can be used to determine if the motor vehicle signal string was received correctly. Please note the abbreviations: M.V.=motor vehicle and E.V.=emergency vehicle in FIGS. 4-8. 
     Variables are defined in process block  54  which store the required parameters. Output pins of the microcontroller  36  are defined in process block  56 . The output pins enable the four direction indicator lamps and the no emergency vehicle indicator lamp  52 . The position of a motor vehicle is obtained by the microcontroller capturing the motor vehicle location signal string  42  in process block  60 . The latitude, longitude and heading data will be extracted from the motor vehicle signal location string  42  in process block  62 . The microcontroller checks for the presence of an emergency location signal string  15  in decision block  64 . If an emergency location signal string  15  is captured, the no emergency indicator lamp  52  is disabled in process block  66  and the program continues to determine the proximity of the emergency vehicle relative to the motor vehicle. If no emergency vehicle is present; the no emergency vehicle indicator lamp  52  is enabled in process block  58 ; the front, rear, left, and right indicator lamps are disabled; and the program loops back to process block  60 . 
     The emergency vehicle location signal string  15  is captured in process block  68 . The latitude and longitude data will be extracted from the emergency vehicle location signal string  15  in process block  70 . The latitude of the motor vehicle is subtracted from the latitude of the emergency vehicle in process block  72  to produce Lat_new. The longitude of the motor vehicle is subtracted from the longitude of the emergency vehicle in process block  74  to produce Long_new. The distance between the motor vehicle and the emergency vehicle is reviewed to see if they are too close in decision block  76 . Preferably, if the distance is less than 200 feet, the emergency vehicle is considered too close. Other values of distance may also be used. 
     If the distance is too close, the right, left, rear, and front indicator lamps are enabled in process block  78 . The program returns to check if the emergency vehicle is still too close to the motor vehicle. If the distance is not too close, the value of Lat_new is reviewed to see if it is equal to zero in decision block  80 . If Lat_new is equal to zero, then Long_new is reviewed to see if it is greater than zero in decision block  82 . If Long_new is greater than zero, then define β=270 in process block  86 . If Long_new is not greater than zero, then define β=90 in process block  84 . 
     If Lat_new is not equal to zero then Long_new is reviewed to see if it is equal to zero in decision block  88 . If Long_new is equal to zero, then Lat_new is reviewed to see if it is greater than zero in decision block  90 . If Lat_new is not greater than zero, then define β=180 in process block  92 . If Lat_new is greater than zero, then define β=0 in process block  94 . If Long_new is not equal to zero, then define the following formula in process block  96 : θ=TAN −1  abs(Long_new/Lat_new). The letters “abs” indicates the absolute value. 
     FIG. 9 shows a coordinate system  200 . The variables Lat_new and Long_new are reviewed to define an angle β in the coordinate system  200  in decision block  98 . Longitude has a horizontal axis and Latitude has a vertical axis. If Lat_new is positive and Long_new is positive then define β=360−θ e in process block  102 . If Lat_new is not positive and Long_new is not positive then review in decision block  104 . If Lat_new is negative and Long_new is positive then define β=180+θ in process block  106 . If Lat_new is not negative and Long_new is not positive then review in decision block  108 . If Lat_new is positive and Long_new is negative then define β=θ in process block  110 . If Lat_new is not positive and Long_new is not negative, define β=180−θ in process block  112 . 
     In decision block  114 , the angle of β is reviewed to see if it&#39;s less than or equal to heading. If β is less than or equal to the heading, then define α=(360−heading)+β in process block  116 . If β is not less than or equal to the heading, then define α=β−heading in process block  118 . In decision block  120 , the angle α is reviewed to see if it less than or equal to 360 degrees and greater than or equal to 331 degrees, or if it less than or equal to 30 degrees and greater than or equal to zero degrees; if so, enable the front indicator lamp  44 , disable the rear, left and right indicator lamps in process block  122 ; if not, continue. In decision block  124 , the angle α is reviewed to see if it less than or equal to 60 degrees and greater than or equal to 31 degrees; if so, enable the front and right indicator lamps, disable the rear and left indicator lamps in process block  126 ; if not, continue. 
     In decision block  128 , the angle α is reviewed to see if it less than or equal to 120 degrees and greater than or equal to 61 degrees; if so, enable the right indicator lamp  50 , disable the left, front and rear indicator lamps in process block  130 ; if not, continue. In decision block  132 , the angle α is reviewed to see if it less than or equal to 150 degrees and greater than or equal to 121 degrees; if so, enable the right and rear indicator lamps, disable the left and front indicator lamps in process block  134 ; if not, continue. In decision block  136 , the angle α is reviewed to see if it less than or equal to 210 degrees and greater than or equal to 151 degrees; if so, enable the rear indicator lamp  46 , disable the front, left, and right indicator lamps in process block  138 ; if not, continue. 
     In decision block  140 , the angle α is reviewed to see if it less than or equal to 240 degrees and greater than or equal to 211 degrees; if so, enable the rear and left indicator lamps, disable the front and right indicator lamps in process block  142 ; if not, continue. In decision block  144 , the angle α is reviewed to see if it less than or equal to 300 degrees and greater than or equal to 241 degrees; if so, enable the left indicator lamp  48 , disable the right, front, and rear indicator lamps in process block  146 ; if not, enable the front and left indicator lamps, disable the rear and right indicator lamps in process block  148 . The program returns to check if the emergency vehicle is still close to the motor vehicle. 
     The following set of constants for describing a particular situation are given by way of example and not by way of limitation: 
     
       
         
           
               
               
               
             
               
                   
                   
               
               
                   
                 Motor Vehicle 
                 Emergency Vehicle 
               
               
                   
                   
               
             
            
               
                   
                 Latitude = 30 
                 Latitude = 34 
               
               
                   
                 Longitude = 70 
                 Longitude = 86 
               
               
                   
                 Heading = 135° 
               
               
                   
                   
               
            
           
         
       
     
     Lat_new=34−30=4 Long_new=86−70=16 
     Angle of the emergency vehicle: θ=TAN −1  abs(16/4)=75.96° 
     Since Lat_new is positive and Long_new is positive: 
     β=360°−75.96°=284.04° Heading=135° 
     β&gt;Heading; Therefore: α=284.04°−135°=149.04° 
     According to the flow chart: α=149.04° lies between 121° and 150° 
     Therefore: right and rear indicator lamps will be enabled. 
     While particular embodiments of the invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects, and therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention.