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CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of priority to U.S. provisional patent application Ser. No. 61/311,626, filed on Mar. 8, 2010. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to animal detection systems, and more particularly to roadside animal detection systems. 
       BACKGROUND OF THE INVENTION 
       [0003]    Existing animal detection systems (“ADSs”) include sensor stations and warning stations. When an animal is detected by one of these sensor stations, the warning stations illuminate lights, which are intended to warn drivers of the presence of the detected animal. 
         [0004]    There are only about 34 different locations in the world (12 in North America and 22 in Europe) where ADSs have been tested or permanently installed. Of those 34, only 8 are still in operation today. The majority of the ADSs that were removed had problems, which included (a) a high rate of false positives (providing a warning when an animal was not in the area), (b) a high rate of false negatives (providing no warning when an animal was in the area), (c) a wide variety of maintenance issues resulting from complex hardware that was difficult to fix and was not readily available, (d) an inability to accurately detect the direction in which an animal is moving, (e) large costs associated with the purchase and installation of ADSs, and (f) large bulky equipment that is not aesthetically pleasing. These problems have discouraged acceptance of ADSs installed along roadways. 
       SUMMARY OF THE INVENTION 
       [0005]    The invention may be embodied as an animal detection system. Such a system may include at least one warning station and at least one sensor station arranged adjacent to a roadway. Each sensor station may include a first sensor attached to the sensor station at a first distance from the ground and at a first distance from the roadway, and a second sensor attached to the sensor station at a second distance from the ground and at a second distance from the roadway. 
         [0006]    A processor may be in communication with the first sensor and the second sensor, and configured to determine the presence of an animal using information provided by the first sensor and the second sensor, and to cause transmission of a warning signal to the at least one warning station when the animal is detected. 
         [0007]    Also, the invention may be embodied as a method of detecting an animal. In one such method, a plurality of sensor stations are arranged adjacent to a roadway. Each sensor station includes a first sensor attached to the sensor station at a first distance from the ground and at a first distance from the roadway, and a second sensor attached to the sensor station at a second distance from the ground and at a second distance from the roadway. Sensor information is transmitted from the plurality of sensor stations to a processor. Information provided by the plurality of sensor stations is analyzed by the processor to determine a condition of an animal. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    For a fuller understanding of the nature and objects of the invention, reference should be made to the accompanying drawings and the subsequent description. Briefly, the drawings are: 
           [0009]      FIG. 1A  is a perspective view of a sensor station according to the invention; 
           [0010]      FIG. 1B  is similar to  FIG. 1A , but a panel has been removed to show components of the sensor station; 
           [0011]      FIG. 1C  is another perspective view of the sensor station shown in  FIG. 1B ; 
           [0012]      FIG. 1D  is a schematic showing two sensor stations and the beams which extend between them; 
           [0013]      FIG. 2A  is a perspective view of a warning station according to the invention; 
           [0014]      FIG. 2B  is a different perspective view of the warning station of  FIG. 2A ; 
           [0015]      FIG. 3A  is a schematic showing an ADS according to the invention used in conjunction with a roadway; and 
           [0016]      FIG. 3B  shows four schematics and text describing how the system might operate to indicate the presence of an animal near a roadway. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0017]    The invention may be embodied as an ADS having two types of stations: (a) sensor stations  10 , and (b) localized warning stations  13  that may be placed at line-of-sight intervals along a road  16 .  FIGS. 1A ,  1 B and  1 C depict a sensor station  10  according to the invention, and  FIGS. 2A and 2B  depict a warning station  13  according to the invention. Each sensor station  10  may have at least two types of sensors. When an animal  19  is detected by a sensor station  10 , a warning signal is sent from the sensor station  10  to one or more of the warning stations  13 . Upon receiving such a warning signal, the warning station  13  provides an indication, which can be interpreted by drivers that an animal  19  has been detected. 
         [0018]    Warning stations  13  may be spaced less than every quarter mile, and preferably are spaced every 250 feet, in order to provide drivers with sufficient advanced warning that an animal  19  has been detected in the area and to allow drivers more time to slow down. A small distance between warning stations  13  may reduce the rate of false negatives reported by drivers. A 250 foot spacing may coincide with the spacing of reflector poles found on many highways, and so it may be possible to mount the warning stations  13  on such reflector poles, thereby saving money during installation. By keeping the spacing of warning stations  13  small, the present invention may allow the location of an animal  19  to be more precisely identified to drivers, which in turn may allow for providing a more meaningful warning to drivers. 
         [0019]    The sensor stations  10  may include at least two types of sensors. The two types of sensors may rely on electromagnetic energy with different frequency ranges. For example, in one embodiment of the invention, each sensor station  10  includes a laser break-beam sensor  22  and also an infrared break-beam sensor  25 . The emitters  28 ,  31  corresponding to the sensors  22 ,  25  may have different angles (i.e. varying areas) of coverage. For example, the first emitter/sensor  22 ,  28  combination may have a smaller area of coverage than the second emitter/sensor  25 ,  31  combination.  FIG. 1D  depicts the beams of two types of energy emitters  28 ,  31 , one emitter  28  having an electromagnetic energy beam  34  that covers a narrow area, and the other having an electromagnetic beam  37  that covers a wide area. For example, the emitter  28  may be a laser and the emitter  31  may be an infrared emitter. By having sensors  22 ,  25  with different areas of detection, the first combination of emitter  28  and sensor  22  may be selected to detect an animal  19  over a narrower area, than the second combination of emitter  31  and sensor  25 . This may be useful, for example, for avoiding false positives. 
         [0020]    A programmed micro-processor/controller  40  (or logic circuit) may be in communication with the sensors  22 ,  25  and the micro-processor/controller  40  may be used to intelligently differentiate an actual crossing event from a false positive or false negative, such as those created by snow thrown from snow plows. The micro-processor/controller  40  may be programmed according to algorithms that use data from the sensor stations  10  regarding which of the sensor stations  10  detected an interruption in both the first sensor  22  and the second sensor  25 , and the order in which those sensors were interrupted to identify an area where the animal  19  is located, and the direction in which the animal  19  is traveling. The micro-processor/controller  40  also may be programmed to use data from the sensor stations  10  to identify which of the warning stations  13  to activate or deactivate. 
         [0021]    The two sensors  22 ,  25  on a sensor station  10  may be spaced apart from each other. In a similar manner, the emitters  28 ,  31  on an adjacent sensor station  10  may be similarly spaced apart from each other. By doing so, the micro-processor/controller  40  can determine the direction in which an animal  19  is moving by identifying the order in which the sensor beams  34 ,  37  are broken. Also, the speed of the animal  19  can be calculated using the time which lapses between detection of the animal  19  by one of the sensors  22  or  25  and detection of the animal  19  by the other sensor  22  or  25 . The direction in which the animal  19  is moving can be used to determine if an animal  19  is moving toward or away from the roadway  16 . If the micro-processor/controller  40  determines that the animal  19  is moving away from the roadway  16 , the warning station  13  may be commanded by the micro-processor/controller  40  to deactivate. 
         [0022]    The beams  34 ,  37  of the sensor stations  10  define a boundary  43 . When one of the sensor stations  10  detects an animal crossing the boundary  43  and the direction in which the animal  19  is moving, the micro-processor/controller  40  may increment a counter in order to keep track of how many animals  19  are near the roadway  16 . For example, when an animal  19  is detected crossing the sensor boundary  43  toward the roadway  16 , the micro-processor/controller  40  may add to the counter, and when an animal  19  is detected crossing the sensor boundary  43  away from the roadway  16 , the micro-processor/controller  40  may subtract from the counter. The counter information may be transmitted to other sensor stations  10 , and in this manner, the ADS can accommodate a situation in which there are multiple animals  19  near the roadway  16 . When the counter returns to zero, the micro-processor/controller  40  may send a signal commanding that the warning lights  46  of the warning stations  13  be turned off. 
         [0023]    The micro-processor/controller  40  may keep track of the length of time that one or more of the sensor beams  34 ,  37  are broken. If a sensor beam  34 ,  37  is broken for an extended period of time, that sensor station  10  can be turned off, thereby shutting down part of the ADS, and eliminating the possibility that drivers would receive a warning indication when there is no animal  19 . Such a condition might exist, for example, due to snow or brush residing in the sensor boundary  43 . By shutting down only a portion of the ADS, other portions of the ADS may continue to provide warnings to drivers. 
         [0024]    Each sensor station  10  may include a warning signal transmitter  49 , which may emit an electromagnetic frequency signal (such as a radio signal) when an animal  19  has been detected. Each warning station  13  may include a warning signal receiver  52 , which may detect when the warning signal transmitter  49  has emitted a warning signal. Upon detection of a warning signal sent by a sensor station  10 , the warning station  13  may provide an indication, which can be interpreted by drivers as a warning that an animal  19  has been detected in the area. For example, the warning station  13  may include lights  46  which are illuminated to warn drivers that an animal  19  has been detected. The lights  46  may provide a message or illuminate a sign that provides a message urging drivers to slow down and/or be aware of the possible presence of an animal  19 . 
         [0025]      FIGS. 1A and 1B  depict a sensor station  10  that is in keeping with the invention. The sensor station  10  includes a solar energy collection panel  55 , which may be electrically connected to a rechargeable battery  58 . The solar energy collection panel  55  and battery  58  can be used to provide electricity to enable the sensors  22 ,  25  to detect animals  19 , and send warning signals to one or more warning stations  13 . In this manner, electric power lines need not be installed, which provides for easy, quick and inexpensive installation of the sensor stations  10 . 
         [0026]    An enclosure  61  protects components from the weather, and may be mounted to a post  64 . Transmitter  49  may extend from the enclosure  61 , and thereby provide a better means to emit an electromagnetic warning signal when an animal  19  has been detected. An accelerometer (not shown) may be included and connected to the micro-processor/controller  40  so that if a sensor station  10  is knocked over (e.g. by a car, snow plow, etc.), that sensor station  10  may be taken off-line. The enclosure  61  may be formed to have suitable shapes and openings to accommodate the sensors  22 ,  25  and emitters  31 ,  34 . 
         [0027]      FIG. 1B  shows additional detail of the sensor station  10  depicted in  FIG. 1A . In  FIG. 1B , a portion of the enclosure  61  has been removed in order to better illustrate that each sensor station  10  may include a micro-processor/controller circuit  40 , battery  58 , and charge controller  67 . The charge controller  67  may govern when and how the battery  58  is charged. A very simple and low cost micro-processor/controller circuit  40 , such as an ATmega  328 , can be used. Such a micro-processor/controller  40  is inexpensive and consumes little power. 
         [0028]    The sensors  22 ,  25  shown in the figures are at different heights above the ground, and differ in height by a distance “V.” While the sensors  22 ,  25  are shown to be situated at different heights, they may be positioned at an equal distance from the ground. However, displacing the sensors  22 ,  25  at different heights, may help protect against false positives. For example, if the system is configured for the detection of larger animals  19 , like a moose, placing the sensors  22 ,  25  at different heights may help protect against the sensors  22 ,  25  from being triggered by a bird flying horizontally past the sensor stations  10 . While the sensors  22 ,  25  may be placed at any height above the ground, it may be advantageous to place the sensors  22 ,  25  greater than two feet above the ground—in this manner, small animals are less likely to be detected by the sensors  22 ,  25 . The emitters  28 ,  31  may be similarly positioned at different heights above the ground. 
         [0029]    Also, the sensors  22 ,  25  shown in the figures are not vertically aligned. Instead, the non-vertical alignment results in a horizontal distance (shown in  FIG. 1A  as “H”) separating the sensors  22 ,  25 . When the horizontal distance “H” is not equal to zero, the ADS obtains an ability to detect the direction in which an animal  19  is moving. For example, if an animal  19  crosses the sensor boundary  43  by tripping the laser sensor  22  prior to the infrared sensor  25 , the system will be able to determine whether the animal  19  is moving toward or away from the roadway  16 . In this manner, the warning signal may be sent when the animal  19  is detected moving toward the road  16 , and then the warning signal may be stopped when the animal  19  is detected moving away from the road  16 . Preferably, the horizontal distance “H” is greater than two inches. The emitters  28 ,  31  may be similarly positioned at different distances from the road  16 . 
         [0030]      FIGS. 2A and 2B  depict a warning station  13  according to the invention. The warning station  13  may be equipped with a solar energy collection panel  70 , which may be electrically connected to a rechargeable battery. The solar collection panel  52  and battery of the warning station  13  can be used to provide electricity to enable components of the warning station  13  to receive warning signals from one or more sensor stations  10 , and provide a warning to drivers, for example, by illuminating the lights  46 . In this manner, electric power lines need not be installed, which provides for easy, quick and inexpensive installation of the warning stations  13 . 
         [0031]      FIGS. 2A and 2B  show that a warning station  13  may include a receiver  52 . Receiver  52  may be used to receive a warning signal from a sensor station  10 . The warning station  13  may include warning lights  46 , for example, in the form of an array of light emitting diodes, which may be used to provide drivers on the roadway  16  with a warning that an animal  19  has been detected. The warning station  13  may be mounted to a post  73  that is located near the roadway  16 . 
         [0032]      FIGS. 3A and 3B  describe how the system of break-beam sensor stations  10  might communicate with the warning stations  13  to provide a driver with a warning.  FIG. 3A  depicts a wild animal  19  breaching the boundary  43 . When the beams of the sensors  22 ,  25  are broken, the presence of the animal  19  at the boundary  43  is determined by the micro-processor/controller  40 , and a warning signal is transmitted to one or more of the warning stations  13 . Upon receipt of the warning signal, warning stations  13  may then illuminate warning lights  46  to provide drivers on the roadway  16  with a warning that an animal  19  has been detected.  FIG. 3B  depicts the process of an animal  19  approaching boundary  43  and crossing the boundary  43 . Once the animal  19  has crossed boundary  43 , warning lights  46  are activated. After the sensor stations  10  detect that the animal  19  has exited boundary  43 , warning lights  46  are deactivated. 
         [0033]    A sensor station  10  and a warning station  13  that are in keeping with the invention may be each made so as to use less power than an ordinary household flashlight. Since the ADS may need to operate only part of the day when animal  19  crossings are most likely, it is believed that a small (1′×1′ 12V) solar panel  55 ,  70  and battery  14  (6″×3″×3″) can power the system for three days without supplemental sunlight. 
         [0034]    Each sensor station  10  of the present invention may be relatively independent of the others. For example, if one sensor station  10  fails, the entire ADS system need not be rendered inoperable. Furthermore, using a predetermined radio frequency band, each of the sensor stations  10  can communicate with at least two other nearby devices (sensor stations  10  and/or warning stations  13 ), which may be within 500 feet of each other. Consequently, the present invention may identify more accurately where along the roadway  16  the animals  19  are located. Such a localized ADS system may allow for advanced warning while also reducing the number of false positives reported. 
         [0035]    Each sensor station  10  may be equipped to send information about its activities to a recording station (not shown), which may be programmed to store information for use in determining how the ADS is operating, and how animals  19  are moving through the area. 
         [0036]    The components of the sensor stations  10  and warning stations  13  may be selected from those currently available from vendors which provide electrical components through mail-order or the Internet. For example, the laser emitter may be laser diode model no. CA-3-4-650A, which is available from Creative Technology Lasers of Walnut Creek, Calif. The infrared emitter may be a photo-electric sensor model no. 1151E-6517, which is available from Eaton Cutler-Hammer of Cleveland, Ohio. Such emitters are inexpensive and consume little power. In doing so, the cost of the system may be kept low, and maintenance may be quickly and easily performed. 
         [0037]    Although the present invention has been described with respect to one or more particular embodiments, it will be understood that other embodiments of the present invention may be made without departing from the spirit and scope of the present invention. Hence, the present invention is deemed limited only by the appended claims and the reasonable interpretation thereof.

Summary:
A system for detecting an animal proximate a roadway is disclosed. In one embodiment of the invention, there is at least one warning station, a plurality of sensor stations, and a processor. Each of the plurality of sensor stations may have a first sensor and a second sensor. The processor may be configured to detect an animal using information provided by the first sensor and the second sensor, and to cause transmission of a warning signal to the at least one warning station when the animal is detected.