Abstract:
The present invention comprises systems and methods for preventing collisions between aircraft and ground vehicles. In one embodiment, a system includes a proximity detection unit and a transducer proximate to a selected structural portion of an aircraft, the proximity detection unit being operable to emit ranging signals through the transducer and to receive reflected signals through the transducer to determine the position of an object within a ranging area adjacent to the structural portion. The system further includes an alarm device coupled to the proximity detection unit that is responsive to a signal generated by the proximity detection unit. In another embodiment, a method includes determining a distance between the ground service vehicle and a selected structural portion of the aircraft when the vehicle is positioned in a ranging area about the aircraft. The method further includes generating a proximity alarm based upon the distance.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates generally to aircraft ground operations, and more particularly to ground vehicle collision prevention systems and methods. 
       BACKGROUND OF THE INVENTION 
       [0002]    Passenger aircraft generally require the performance of a variety of different tasks following the termination of a specific flight. For example, the aircraft must be refueled, cargo must be unloaded, the cabin of the aircraft must be cleaned, the lavatory wastewater must be removed, and the galley must be re-provisioned, among other tasks. Accordingly, relatively long turnaround times are often encountered in the operation of passenger aircraft, which adversely affects the return on investment for an aircraft operator since the aircraft cannot generate revenue while sitting on the ground. Considerable effort has therefore been devoted to systems and methods for making the aircraft ready for flight in less time. 
         [0003]    One conventional method for preparing an aircraft for flight involves the use of a number of special-purpose ground vehicles that may simultaneously perform specific ground service tasks.  FIG. 1  is a plan view of a transport aircraft  10  positioned in a parking area  12  at an airport that will be used to describe at least a portion of the ground service vehicles commonly encountered during aircraft service operations. The ground service vehicles generally maneuver about the aircraft  10  to occupy positions about the aircraft  10  in order to perform a specific task related to servicing the aircraft  10 . For example, passenger-loading ramps  14  may be maneuvered into position near aircraft exit locations to permit passenger access to the aircraft  10 . Cargo loading conveyors  16  may be positioned adjacent to cargo compartment doors to permit cargo to be loaded and unloaded from the aircraft  10 . Cabin service vehicles  18  may also be positioned near exit locations in the aircraft  10  to permit the galley to be re-supplied, and to perform other tasks related to maintaining the cabin of the aircraft  10 . Fuel service vehicles  20  may be positioned near fuel service ports in order to refuel the aircraft  10 . A potable water vehicle  22  and a lavatory service vehicle  24  may be positioned near the aircraft  10  in order supply the aircraft  10  with potable water, and to remove wastewater from the airplane  10 . Still other types of ground vehicles may maneuver about the aircraft  10 . For example, a tow tractor  26  is generally required to move the aircraft  10  about the parking area  12 . Moreover, cargo pallet trains  28  may frequently maneuver about the aircraft  10  so that cargo may be transported from an airport terminal facility to the cargo loading conveyors  16 . 
         [0004]    Consequently, during the performance of various ground service operations, a plurality of service vehicles may be maneuvering and/or positioned about the aircraft  10 . A risk therefore exists that a service vehicle may inadvertently collide with a portion of the aircraft  10  while moving about the aircraft  10 . Such a collision may result in significant damage to the aircraft  10 , requiring a costly and time-consuming repair before the aircraft  10  is returned to service. Since non-metallic composite components are increasingly replacing conventional metallic structures on passenger aircraft in order to reduce weight, the likelihood that significant damage may result from a ground service vehicle collision has accordingly increased. Moreover, selected portions of the aircraft  10  are particularly susceptible to damage while the aircraft  10  is positioned on the ground. For example, landing gear doors, cargo loading doors and passenger access doors are generally maintained in an open position during ground operations, and may be relatively easily damaged by even a minor collision. Even in cases where damage to the aircraft  10  is less significant, relatively expensive flight delays are often incurred since a mandated inspection of the damaged area must be performed to determine if the damage is within allowable limits. 
         [0005]    Accordingly, there is a need for a systems and methods that at least partially prevent a collision between a ground service vehicle and an aircraft. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention comprises systems and methods for preventing collisions between aircraft and ground vehicles. In one aspect, a ground vehicle collision prevention system includes a proximity detection unit positioned on an aircraft and coupled to at least one transducer proximate to at least one selected structural portion of the aircraft. The proximity detection unit is operable to emit ranging signals through the at least one transducer and to receive reflected signals through the at least one transducer to determine the position of an object within a ranging area adjacent to the selected structural portion. The system further includes at least one alarm device coupled to the proximity detection unit that is responsive to a proximity alarm signal generated by the proximity detection unit. In another aspect of the invention, a method of preventing a collision between an aircraft and a ground service vehicle includes determining a distance between the ground service vehicle and a selected structural portion of the aircraft when the vehicle is positioned in a ranging area about the aircraft. The method further includes generating a proximity alarm based upon the distance. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0007]    The preferred and alternative embodiments of the present invention are described in detail below with reference to the following drawings. 
           [0008]      FIG. 1  is a plan view of a transport aircraft positioned in a parking area at an airport in accordance with the prior art; and, 
           [0009]      FIG. 2  is a is a block diagrammatic view of a ground vehicle collision prevention system according to an embodiment of the invention; 
           [0010]      FIG. 3  is a block diagrammatic view of a ground vehicle collision prevention system according to another embodiment of the invention; 
           [0011]      FIG. 4  is a block diagrammatic view of a ground vehicle collision prevention system according to still another embodiment of the invention; 
           [0012]      FIG. 5  is a block diagrammatic view of a ground vehicle collision prevention system according to still yet another embodiment of the invention; 
           [0013]      FIG. 6  is a block diagrammatic view of a ground vehicle collision prevention system according to a further embodiment of the invention; and 
           [0014]      FIG. 7  is a side elevation view of an aircraft having one or more of the disclosed embodiments of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0015]    The present invention relates to ground vehicle collision prevention systems and methods. Many specific details of certain embodiments of the invention are set forth in the following description and in  FIGS. 2 through 7  to provide a thorough understanding of such embodiments. One skilled in the art, however, will understand that the present invention may have additional embodiments, or that the present invention may be practiced without several of the details described in the following description. 
         [0016]      FIG. 2  is a block diagrammatic view of a ground vehicle collision prevention system  30  according to an embodiment of the invention. The system  30  includes a proximity detection unit  32  operable to generate ranging signals  34  and to detect return signals  36  reflected from objects positioned within a ranging area  38 . The proximity detection unit  32  is further coupled to at least one transducer  40  (two shown) that is positioned proximate to an aircraft structural portion  41 . The aircraft structural portion  41  may comprise a skin portion of a fuselage of an aircraft, or other portions coupled to the fuselage, such as a passenger or a cargo door. The portion  41  may also comprise a portion of at least one wing coupled to the fuselage. Moreover, aircraft structural portion  41  may comprise a structure that protrudes from fuselage, such as a drain mast, Pitot tube, or other similar structures. The proximity detection unit  32  may be positioned on the aircraft, or may be positioned proximate to the aircraft on a temporary support that is placed near the aircraft when the aircraft is parked on the ground. 
         [0017]    The at least one transducer  40  is operable to emit the ranging signals  34  and to collect the return signals  36 . Accordingly, and in a particular embodiment, the proximity detection unit  32  and the at least one transducer  40  may comprise a radio frequency detection and ranging apparatus (RADAR) operating at microwave frequencies. Alternately, and in another particular embodiment, the unit  32  and the at least one transducer  40  may comprise an ultrasonic detection and ranging apparatus, wherein the transducer  40  is configured to emit ranging signals  34  at ultrasonic frequencies, and also receive ultrasonic return signals  36 . In other particular embodiments, the proximity detection unit  32  and the at least one transducer  40  may comprise a light-based detection and ranging apparatus (LIDAR) using a photo-emitter and a photo-detector, or an electromagnetic detection and ranging device that relies on inductive effects to detect an object positioned within the ranging area  38 , although other detection and ranging apparatus are known to those skilled in the art. 
         [0018]    The system  30  further includes at least one alarm device  42 , which may include an audio alarm device  44  and a visual alarm device  46 . The audio alarm device  44  and the visual alarm device  46  are operable to generate acoustic energy and light, respectively, corresponding to an alarm signal generated by the proximity detection unit  32 . 
         [0019]    The at least one alarm device  42  may be positioned remotely from the proximity detection unit  32  so that the acoustic energy and light corresponding to the alarm signal may be perceived within the ranging area  38 . For example, the audio alarm device  40  may comprise a loudspeaker positioned within a wheel well opening of an aircraft, while the visual alarm device  44  may include an incandescent light source positioned on an exterior portion of the aircraft structural portion  41 . 
         [0020]    Still referring to  FIG. 2 , the operation of the ground vehicle collision prevention system  30  will now be discussed. The proximity detection unit  32  generates ranging signals  34  that are reflected from a ground service vehicle  48  positioned within the ranging area  38  to yield return signals  36 . Accordingly, a distance between the aircraft structural portion  41  and the ground service vehicle  48  may be determined by measuring a time delay between the emission of the ranging signal  34  and the detection of the return signal  36 , and multiplying the resulting time delay by the propagation speed of the ranging signal  34 . Accordingly, for a ranging apparatus that employs electromagnetic emissions, the speed of light is used as the propagation speed, while for an acoustic-based ranging apparatus, an acoustic propagation speed is appropriate. The proximity detection unit  32  may be configured to generate alarm signals depending on the distance between the aircraft structural portion  41  and the ground service vehicle  48 . 
         [0021]    In one particular embodiment, the ranging area  38  may be sub-divided into a near field region  50 , an intermediate field region  52 , and a far-field region  54  so that the proximity detection unit  32  generates a first alarm signal characteristic when the ground service vehicle  48  is positioned in the near field region  50 , a second alarm signal characteristic when positioned in the intermediate field region  52 , and a third alarm signal characteristic when the ground service vehicle  48  is positioned in the far field region  54 . The first, second and third signal characteristics may be selected to provide an operator of the vehicle  48  with a distinct and readily recognizable aural or visual indication that reflects the distance between the vehicle  48  and the aircraft structural portion  41 . In another particular embodiment, the first signal characteristic includes a steady audible tone having a frequency of approximately 3000 Hz, the second signal characteristic includes an intermittent audible tone having a first repetition rate and a frequency of approximately 1500 Hz, while the third signal characteristic includes an intermittent audible tone having a second repetition rate and a frequency of approximately 500 Hz. Thus, as the vehicle  48  moves from the far-field region  54  to the near field region  50 , the operator of the vehicle  48  perceives a succession of different aural indications that vary in frequency and repetition rate. 
         [0022]    Still other alarm signal characteristics may be employed to provide the operator of the vehicle  48  with an aural indication of the distance between the vehicle  48  and the aircraft structural portion  41 . For example, the proximity detection unit  32  may be configured to generate a plurality of audible sounds, so that a distinct sound applies to a selected portion of the aircraft structure. For example, an intermittent audible tone having a pulse duration that is continuously frequency modulated from approximately 2500 Hz to approximately 1500 Hz is readily recognizable as a “chirp” which may correspond to a first selected aircraft structural portion, while another intermittent audible tone with a pulse duration that is step-wise frequency modulated from approximately 1500 Hz to approximately 1000 Hz is readily recognizable as a “cuckoo” which may correspond to a second selected aircraft structural portion. Having different distinct sounds assigned to different portions of the aircraft structure may advantageously assist operators of different vehicles approaching different portions of the aircraft structure to discriminate between warning signals. 
         [0023]    In another particular embodiment, the proximity detection unit  32  of  FIG. 2  may be configured with a voice synthesis apparatus operable to generate a verbal alarm signal characteristic, which advantageously may also provide a verbal indication of the location of the system  30 . For example, the voice synthesis apparatus may be configured to generate a verbal alarm signal such as “REAR CARGO DOOR-CAUTION” when the vehicle  48  is positioned in the intermediate field region  52  and generate a verbal alarm signal such as “REAR CARGO DOOR-WARNING” when the vehicle  48  moves into the near field region  50 . 
         [0024]      FIG. 3  is a block diagrammatic view of a ground vehicle collision prevention system  60  according to another embodiment of the invention. Many of the details of the system  60  have been discussed in detail in connection with previous embodiments, and in the interest of brevity, will not be described further. The system  60  includes a proximity detection unit  32  coupled to at least one transducer  40  that is positioned proximate to an aircraft structural portion  41 . The transducer  40  emits the ranging signals  34  generated by the proximity detection unit  32  and collects the return signals  36  reflected from a ground service vehicle  62 . In this embodiment, a ground service vehicle  62  includes a proximity detection unit  64  that is coupled to at least one transducer  66  that is positioned on a portion of the vehicle  62  that emits ranging signals  68  generated by the proximity detection unit  64  and to collect return signals  70  reflected from the aircraft structural portion  41 . The proximity detection unit  64  is also configured to generate alarm signals depending on the distance between the aircraft structural portion  41  and the ground service vehicle  62 , which may be communicated to an audio alarm device  72 , although a visual alarm device (not shown in  FIG. 3 ) may also be present. 
         [0025]    The foregoing system  60  provides two independent proximity detection units that advantageously provide redundancy. As a result, if a failure occurs in either the proximity detection unit  32  or the proximity detection unit  64 , or in any of the components associated with the proximity detection unit  32  or the proximity detection unit  64 , the collision avoidance capabilities afforded by the system  60  remain intact. This capability may be important when power has been removed from the aircraft, or a failure has occurred in the proximity detection unit  32 . The foregoing system  60  has further advantages. For example, if the transducer  40  is inadvertently obstructed and cannot exchange the signals  30  and  36  with the vehicle  62 , the proximity detection unit  64  and the transducer  66  on the vehicle  62  may remain operational to provide the desired collision avoidance awareness to an operator of the vehicle  62 . 
         [0026]      FIG. 4  is a block diagrammatic view of a ground vehicle collision prevention system  80  according to still another embodiment of the invention. Many of the details of the system  80  have been discussed in detail in connection with previous embodiments, and in the interest of brevity, will not be described further. The system  80  includes a proximity detection unit  82  operable to generate ranging signals  34  and to detect return signals  36  within the ranging area  38  through at least one transducer  40  that is positioned proximate to the aircraft structural portion  41 . The alarm signals generated by the proximity detection unit  82  may be communicated to an audio alarm device  44 , or other alarm devices. In this embodiment, the proximity detection unit  82  further includes a control transmitter  84  that is coupled to a control transmitting transducer  86 . The control transmitter  84  is further configured to receive alarm signals generated by the unit  82 . The control transmitter  84  and the control transmitting transducer  86  are operable to transmit a control signal  88  to a control receiving transducer  90  that is coupled to a control receiver  92  positioned on a ground service vehicle  94 . In one particular embodiment, the control transmitter  84  and the control receiver  92  are configured to transmit the control signal  88  wirelessly. In alternate embodiments, a control wire, cable, or other physical connection may be employed. Accordingly, the transmitter  84  may communicate the control signal  88  to the receiver  92  by electromagnetic means, including radio frequency (RF) and light, or by ultrasonic means. 
         [0027]    Still referring to  FIG. 4 , the control receiver  92  is coupled to a control system  96  positioned on the vehicle  94  that is operable to stop movement of the vehicle  94  when the critical proximity signal is received. For example, if the vehicle  96  is an electric powered vehicle, the control system  96  may be configured to interrupt current between an electrical power supply and an electric traction motor in the vehicle  96 . Alternately, if the vehicle  96  is powered by a conventional gasoline or diesel engine, the control system  96  may be configured to interrupt the operation of an ignition system, or interrupt a fuel flow to the engine, respectively. The control system  96  may be further configured to actuate a vehicle braking system in response to receiving the critical proximity signal, or any combination of the above-referenced actions may be employed. 
         [0028]    The operation of the system  80  of  FIG. 4  will now be described. When the ground service vehicle  94  is positioned within the far field region  54 , or within the intermediate field region  52 , alarm signals as previously described may be generated by the proximity detection unit  82 , which may be relayed to an operator of the vehicle  94  by the audio alarm device  44 . When the vehicle  94  moves from the intermediate field region  52  and into the near field region  50 , the alarm signal generated by the proximity detection unit  82  again changes, and a corresponding audible signal is relayed to the operator of the vehicle  94  by the audio alarm device  44 . At a critical distance “d”, a critical alarm signal is generated by the proximity detection unit  82 , which is communicated to the control transmitter  84 . The control signal  88  is transmitted to the control receiver  92 , which, in turn, communicates an appropriate signal to the control system  96  to stop motion of the vehicle  96 . 
         [0029]      FIG. 5  is a block diagrammatic view of a ground vehicle collision prevention system  100  according to still yet another embodiment of the invention. Many of the details of the system  100  have been discussed in detail in connection with previous embodiments, and in the interest of brevity, will not be described further. The system  100  includes a proximity detection unit  102  operable to generate ranging signals  34  and to detect return signals  36  within the ranging area  38  through at least one transducer  40 . The alarm signals generated by the proximity detection unit  102  may be communicated to an audio alarm device  44 , or other similar alarm devices in order to inform the operator of a ground service vehicle  104 . The proximity detection unit  102  further includes an aircraft processor  103  that includes selected information pertaining to the aircraft, as will be discussed in greater detail below. 
         [0030]    As further shown in  FIG. 5 , the proximity detection unit  102  also includes a data link transceiver  106  that is coupled to a data link transducer  108 . The data link transceiver  106  and the data link transducer  108  are operable to exchange signals  110  with a corresponding data link transceiver  112  through a data link transducer  114 , thus comprising a data link  111  between the proximity detection unit  102  and the vehicle  104 . The data link transducer  112  may be coupled to a data link processor  113  that provides data access and other control functions, as will be explained in detail below. In this embodiment, the data link transceiver  106  and the data link transceiver  112  are configured to communicate the signals  110  wirelessly. Accordingly, the data link transceiver  106  and the data link transceiver  112  may communicate the signals  110  by electromagnetic means, including radio frequency (RF) and light, or by ultrasonic means. 
         [0031]    The operation of the system  100  of  FIG. 5  will now be described. As the vehicle  104  approaches the aircraft structural portion  41 , the proximity detection unit  102  determines the position of the vehicle  104  in the manner previously described. The data link  111  further assists the vehicle  104  by exchanging information with the proximity detection unit  102 . For example, the data link processor  113  may contain a memory device having information regarding the vehicle  104 , including vehicle dimensions, which is communicated to the proximity detection unit  102  by the data link  111 . The aircraft processor  103  correspondingly contains aircraft-related information, which may include information regarding vehicle compatibility. The proximity detection unit  102  may accordingly alter the locations of the near field region  50 , the intermediate field region  52  and the outer field region  54  depending on the information received from the data link processor  113 . Alternately, the data link processor  113  may communicate with the proximity detection unit  102  through the data link  111  to determine if the vehicle  104  is compatible with the aircraft on which the proximity detection unit  102  is positioned. For example, if a ground service vehicle such as a cargo-loading conveyor (see  FIG. 1 ) is suitable for use with a Boeing Model 737 airplane, the cargo loading conveyor would identify itself to the proximity detection unit  102  positioned on 737 airplane through the data link  111 . The proximity detection unit  102 , in turn, accesses the aircraft processor  103  and, assuming the aircraft is a Boeing Model 737, generates a return signal that is transmitted through the data link  111  acknowledging the compatibility. In contrast, if the same conveyor identified itself to a Boeing Model 747 airplane, the conveyor would receive a return signal by means of the data link  111  indicating that the conveyer is not suitable for use with the 747 airplane. An identification of aircraft-ground vehicle compatibility may thus advantageously prevent damage to an aircraft through the use of incompatible equipment. 
         [0032]    The ability to communicate signals  110  by means of the data link  111  may afford still other advantages. For example, in still another particular embodiment, the data link  111  may be used to communicate information to the proximity detection unit  102  that includes an identity of an operator of the vehicle  104 , and if a collision occurs between the vehicle  104  and the aircraft structural portion  41 , the data link  111  may be further employed to communicate the time of the collision and the location of the aircraft structural portion  41 . 
         [0033]      FIG. 6  is a block diagrammatic view of a ground vehicle collision prevention system  120  according to a further embodiment of the invention. The system  120  includes a proximity detection unit  122  operable to receive ground position information  124  through a receiver  126 , such as a Ground Positioning System (GPS) receiver. A vehicle  128  is similarly configured to receive ground position information  130  through a receiver  132 , which may also be a GPS receiver. The receiver  132  is coupled to a transceiver  134  operable to exchange signals  136  with the proximity detection unit  122 , thus forming a data link  138  between the proximity detection unit  122  and the vehicle  128  through which the ground positioning information  124  and the ground positioning information  130  may be exchanged. Accordingly, the ground position information  124  pertaining to the aircraft structural portion  41  and the ground position information  130  of the vehicle  128  may be processed by the proximity detection unit  122  to determine a relative distance between the aircraft structural portion  41  and the vehicle  128 , and to generate appropriate alarm signals (or control signals, etc.) as the vehicle  128  moves through the ranging area  38 . 
         [0034]    Those skilled in the art will also readily recognize that the foregoing embodiments may be incorporated into a wide variety of different systems. Referring now in particular to  FIG. 7 , a side elevation view of an aircraft  300  having one or more of the disclosed embodiments of the present invention is shown. With the exception of the embodiments according to the present invention, the aircraft  300  includes components and subsystems generally known in the pertinent art, and in the interest of brevity, will not be described further. The aircraft  300  generally includes one or more propulsion units  302  that are coupled to wing assemblies  304 , or alternately, to a fuselage  306  or even other portions of the aircraft  300 . Additionally, the aircraft  300  also includes a tail assembly  308  and a landing assembly  310  coupled to the fuselage  306 . The aircraft  300  further includes other systems and subsystems generally required for the proper operation of the aircraft  300 . For example, the aircraft  300  includes a flight control system  312  (not shown in  FIG. 7 ), as well as a plurality of other electrical, mechanical and electromechanical systems that cooperatively perform a variety of tasks necessary for the operation of the aircraft  300 . Accordingly, the aircraft  300  is generally representative of a commercial passenger aircraft, which may include, for example, the 737, 747, 757, 767 and 777 commercial passenger aircraft available from The Boeing Company of Chicago, Ill. Although the aircraft  300  shown in  FIG. 7  generally shows a commercial passenger aircraft, it is understood that the various embodiments of the present invention may also be incorporated into flight vehicles of other types. Examples of such flight vehicles may include manned or even unmanned military aircraft, rotary wing aircraft, or even ballistic flight vehicles, as illustrated more fully in various descriptive volumes, such as Jane&#39;s All The World&#39;s Aircraft, available from Jane&#39;s Information Group, Ltd. of Coulsdon, Surrey, UK. 
         [0035]    With reference still to  FIG. 7 , the aircraft  300  may include one or more of the embodiments of the ground vehicle collision prevention system  314  according to the present invention, which may operate in association with the various systems and sub-systems of the aircraft  300 . Although  FIG. 7  shows the one or more embodiments of the ground vehicle collision prevention system  314  as an integral portion of the aircraft  300 , one skilled in the art will readily understand that the one or more embodiments of the ground vehicle collision prevention system  314  may also be incorporated into a portable device that may be remotely positioned and separately coupled to the aircraft  300 . 
         [0036]    While preferred and alternate embodiments of the invention have been illustrated and described, as noted above, many changes can be made without departing from the spirit and scope of the invention. Accordingly, the scope of the invention is not limited by the disclosure of these preferred and alternate embodiments. Instead, the invention should be determined entirely by reference to the claims that follow.