Abstract:
An avionics wake turbulence awareness system and method for use in an aircraft includes an ADS-B receiver that is adapted to be positioned in an equipped aircraft and receives ADS-B transmissions from other aircraft. A control system is responsive to the ADS-B receiver and determines an identity for each of the other aircraft and determines a movement of each of the other aircraft relative to the equipped aircraft. The control system determines a flight path history of each of the other aircraft from their respective identities and movements relative to the equipped aircraft. An output device is responsive to the control system to provide guidance to a pilot of the equipped aircraft to avoid an encounter with a wake turbulence caution area that is defined by a flight path history of another aircraft. The control system evaluates the relative risk of the equipped aircraft encountering the respective wake turbulence caution areas of each of the other aircraft, and after selecting an aircraft of the other aircraft with a highest priority, provides guidance to the pilot of the equipped aircraft to avoid an encounter with a wake turbulence caution area of the selected aircraft.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority from U.S. provisional patent application Ser. No. 62/158,340, filed on May 7, 2015, the disclosure of which is hereby incorporated herein by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention is directed to an aircraft avionic system and method, and in particular, to a system and method for an equipped aircraft to avoid a potential wake turbulence generated by another aircraft. 
         [0003]    While wake turbulence can be a threat to safety of any aircraft, it is particularly dangerous for medium to small aircraft. Such wake turbulence is particularly dangerous immediately before landings and immediately after takeoffs. The task of avoiding potential wake turbulences of other aircraft is made more difficult when a pilot of an aircraft is forced to monitor the position and flight path history of multiple other aircraft. 
       SUMMARY OF THE INVENTION 
       [0004]    The present invention provides awareness to a pilot of a risk posed by wake turbulence of other aircraft. Moreover, the present invention may be implemented as a system that is based upon information that is readily available from avionic systems of even small aircraft to provide awareness of a risk of encountering such wake turbulence. The invention is based upon a recognition that it is difficult for a pilot to visually estimate the distance of another aircraft and/or the time it may take to reach the flight path of that aircraft and any accompanying potential wake turbulence. As a result of such inaccuracy, it is possible for the pilot to encounter a wake turbulence even when the pilot estimates that the aircraft is sufficiently spaced from another aircraft. ADS-B systems are becoming popular in aircraft of all sizes and will soon be required on most aircraft systems. ADS-B systems receive transmissions from other aircraft in the form of an 8 character field that consists of either a flight identifier for a commercial airliner or a tail number for general aviation aircraft, as well as the relative position of the identified aircraft with respect to the equipped aircraft. With such information, the control system of the equipped aircraft creates a flight path history for each aircraft in its vicinity. Wake turbulence caution areas that follow each of those other aircraft are defined by their aircraft type and follow the respective bread crumbs of the their respective flight path histories. In other words, this wake turbulence caution area may be modified to account for lead aircraft type, typical wake vortex, descent rate, reported winds, and the like. By tracking the flight path history of an intruding aircraft, the system of the equipped aircraft can provide a visual and/or aural advisory to the pilot of a potential wake turbulence associated with the intruding aircraft. The system can also report to the pilot the time and distance from the lead aircraft which will aid the pilot in keeping appropriate spacing from the lead aircraft. 
         [0005]    An avionics wake turbulence awareness system and method for use in an aircraft, according to an aspect of the invention, includes an ADS-B receiver that is adapted to be positioned in an equipped aircraft and receives ADS-B transmissions from other aircraft. A control system is responsive to the ADS-B receiver and determines a respective identity of each of the other aircraft and their respective movements relative to the equipped aircraft. The control system determines a flight path history for each of the other aircraft from their respective identities and movements relative to the equipped aircraft. An output device is responsive to the control system to provide guidance to a pilot of the equipped aircraft to avoid an encounter with a wake turbulence caution area that is defined by a flight path history of another aircraft. 
         [0006]    The guidance provided may include distance and flight time to the other aircraft. The flight time is based upon the ground speed of the other aircraft. The guidance may also include an indication that the equipped aircraft is at risk of encountering the potential wake turbulence of the at least one other aircraft. A pilot notification device may be provided that is responsive to the guidance in order to alert a pilot that the equipped aircraft is at risk of encountering the wake turbulence caution area of another aircraft. The notification device may include a display that is adapted to provide a visual indication that the equipped aircraft is at risk of encountering the wake turbulence caution area of the other aircraft. The visual indication may include an icon adjacent a depiction of the other aircraft on the display. The visual indication may include a chevron trailing the depiction of the other aircraft on the display. The visual indication may include a display of distance and flight time to the other aircraft. The notification device may also include an aural announcement via a speaker or pilot&#39;s headset that the equipped aircraft is at risk of encountering the wake turbulence caution area of the other aircraft. 
         [0007]    The avionic notification may include a visual indication of the flight path history of the other aircraft. The control system may be capable of determining flight path histories of each of the other aircraft and evaluating the relative risk of the equipped aircraft encountering the respective wake turbulence caution areas of each of the other aircraft. After selecting an aircraft of the other aircraft with a highest priority, guidance is provided to the pilot of the equipped aircraft to avoid an encounter with a wake turbulence caution area of the selected aircraft. The control system may evaluate and prioritize the other aircraft according to category types, such that other aircraft smaller than the equipped aircraft have a lower priority. 
         [0008]    These and other objects, advantages, and features of this invention will become apparent upon review of the following specification in conjunction with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is an exemplary block diagram of an avionics wake turbulence awareness system in accordance with an embodiment of the present disclosure; 
           [0010]      FIG. 2  is an exemplary block diagram of an ADS-B receiver and controller of the avionics wake turbulence awareness system illustrated in  FIG. 1 , in accordance with an embodiment of the present disclosure; 
           [0011]      FIG. 3  is an exemplary output device of the avionics wake turbulence awareness system illustrated in  FIG. 1 , in accordance with an embodiment of the present disclosure; 
           [0012]      FIG. 4  is a flow diagram of the steps to a computer-implemented method for wake turbulence awareness in an aircraft, in accordance with an embodiment of the present disclosure; 
           [0013]      FIGS. 5A and 5B  illustrate exemplary wake caution areas defining the boundaries of potential wake turbulences in accordance with an embodiment of the present disclosure; and 
           [0014]      FIGS. 6A and 6B  illustrate the exemplary wake caution areas of  FIGS. 5A and 5B  that follow flight path histories in accordance with an embodiment of the present disclosure. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0015]    Referring now to the drawings and the illustrative embodiments depicted therein, an avionics wake turbulence awareness system for use in an aircraft is disclosed.  FIG. 1  illustrates an exemplary avionics wake turbulence awareness system  100 . As discussed herein, a receiver  102  of the wake turbulence awareness system  100  may be an ADS-B receive that is capable of receiving ADS-B transmissions from other aircraft. The transmission be in the form of an 8-character field that consists of either a flight identifier for a commercial airliner or a tail number for a general aviation aircraft, as well as the relative position of the identified aircraft with respect to the equipped aircraft. The wake turbulence awareness system  100  includes a control system  104  (also known herein as a controller  104 ) that is responsive to the ADS-B receiver  102  in order to receive transmissions from other aircraft. The wake turbulence awareness system  100  may include any form of ADS-B receiver  102  and accompanying controller  104 , and may be of the type disclosed in commonly assigned U.S. Pat. No. 9,285,472 of Blake R. Getson et al., entitled MULTI-LINK TRANSPONDER FOR AIRCRAFT AND METHOD OF PROVIDING MULTI-LINK TRANSPONDER CAPABILITY TO AN AIRCRAFT HAVING AN EXISTING TRANSPONDER, the disclosure of which is hereby incorporated herein by reference in its entirety. As also discussed herein, and described in detail in commonly owned U.S. Pat. No. 8,736,465 issued to Steve M. Rutherford et al., entitled “AIRCRAFT TRAFFIC DISPLAY,” the disclosure of which is hereby incorporated herein by reference, ADS-B signals are received by the ADS-B receiver  102 , and the controller  104  accessing a database in a memory  106 , looks up specific aircraft information based upon a received ICAO code contained within the ADS-B transmission. As illustrated in  FIG. 1 , the wake turbulence awareness system  100  also includes an output device  108 , which comprises a visual display screen  110 . The output device  108  may also optionally include an annunciator  112 . The annunciator  112  may be implemented as one or more speakers in the aircraft and via a pilot&#39;s aural headset. The output device  108  is responsive to the control system  104  to provide guidance to a pilot of the equipped aircraft to avoid encounters with potential wake turbulences of other aircraft. 
         [0016]      FIG. 2  illustrates that the ADS-B receiver  102  of  FIG. 1  may comprise a 1090 ES receiver  102   a  and/or a 978 MHz UAT receiver  102   b . As illustrated in  FIG. 2 , either of the 1090 ES receiver  102   a  and the 978 MHz UAT receiver  102   b  forwards the received ADS-B transmissions to the controller  104  for processing. 
         [0017]      FIG. 3  illustrates an exemplary output device  108  that incorporates a display screen  110  and an annunciator  112 . The guidance may include a visual distance indication  302  indicating a distance in nautical miles to another aircraft. The guidance may include a time indication  304  advising the pilot of an estimated time behind the other aircraft or to the potential wake encounter computed at least in part from the ADS-B system. The guidance may include a visual indication  306  that the equipped aircraft is at risk of encountering the wake turbulence caution area of the other aircraft. In an aspect of the present invention, an icon  306  is used as a visual indication  306 . As illustrated in  FIG. 3 , the icon  306  may be placed adjacent a depiction of the other aircraft on the display  110 . The icon  306  may take other forms, but is shown as a chevron trailing the depiction of the other aircraft on the display  110 . As discussed below, and illustrated in  FIGS. 6A and 6B , the icon  306  may be paired with a visual depiction of the flight path history  602  of the other aircraft in order to give the pilot a better understanding of the form of potential wake turbulences that should be avoided. As illustrated in  FIGS. 6A and 6B , and discussed herein, such visual indication of the flight path  602  of the other aircraft may be in the form of dotted “bread crumbs” or other intuitive indications of the flight path history  602  of the other aircraft. 
         [0018]    As illustrated in  FIGS. 1 and 3 , the output device  108  may include an aural annunciator  112  that verbally notifies the pilot via an aural announcement that the equipped aircraft is at risk of encountering the wake turbulence caution area of the other aircraft. 
         [0019]      FIG. 4  illustrates the exemplary steps to a computer-implemented method for providing guidance to a pilot of an equipped aircraft that the equipped aircraft is at risk of encountering a wake turbulence caution area of another aircraft. In step  402  of  FIG. 4 , an ADS-B Out message is received from an intruding aircraft. As used herein, an “intruding aircraft” is merely another aircraft leading the equipped aircraft that occupies the same general airspace as the equipped aircraft. Such an intruding aircraft has a potential wake turbulence that the equipped aircraft may need to avoid. In step  404  of  FIG. 4 , the received ADS-B Out message is decoded to determine position, flight path, and aircraft ID of the intruding aircraft. In step  406  of  FIG. 4 , data corresponding to the aircraft ID is retrieved from the database in the memory  106  based upon the determined aircraft ID. 
         [0020]    In step  408  of  FIG. 4 , vertical and horizontal limits of a wake turbulence caution area are determined based upon the determined aircraft type, speed, and flight path. As discussed herein, a wake turbulence caution area may be defined with regards to its length, height, and width. For example, the defined length may be three minutes in length, based upon the intruding aircraft&#39;s ground speed, a height or vertical dimension may be a thousand feet in height, while a width or horizontal dimension may also be a thousand feet in width. As discussed herein, the vertical and horizontal dimensions are variable based upon the intruding aircraft&#39;s category type. For example, larger aircraft types define larger horizontal and vertical dimensions. In step  410  of  FIG. 4 , historical positions of the intruding aircraft are recorded in the memory  106 . Such recorded positions may be used, as discussed herein, to define the location of any potential wake vortex/turbulence. 
         [0021]    In step  412  of  FIG. 4 , the equipped aircraft&#39;s position and flight path are computed based upon positioning data received from a global positioning system (GPS) receiver  114  in the equipped aircraft. As illustrated in  FIG. 1 , based upon signals received from orbiting GPS satellites, the GPS receiver  114  determines the position of the equipped aircraft and transmits the positioning data to the controller  104 . In step  414  of  FIG. 4 , based upon the recorded historical positions of the intruding aircraft (i.e., a flight path history), and the computed position and flight path of the equipped aircraft, a distance and time from the equipped aircraft to the intruder and its associated wake turbulence caution area is determined. As discussed herein, once a location and flight history of the intruder aircraft is determined, the wake turbulence caution area may be defined. 
         [0022]    In steps  416  and  418  of  FIG. 4 , if the controller  104  determines that the equipped aircraft is at risk of entering the wake turbulence caution area associated with the intruder aircraft, a wake advisory will be transmitted to the output device  108 . In step  418  of  FIG. 4 , a visual wake advisory is displayed in the display screen  110  and an audible wake advisory is announced in the annunciator  112 . As illustrated in  FIG. 3 , the text box “WAKE,” the icon  306  (e.g., chevrons), a determined nautical mile range  302  to the potential wake vortex/turbulence, and a determined time  304  to enter the wake turbulence caution area will be displayed on the display screen  110 . In an aspect of the present invention, if the equipped aircraft&#39;s flight path will enter the area of potential wake vortex/turbulence, or violate a recommended spacing between aircraft, the controller will indicate the above wake vortex/turbulence caution thirty seconds prior. As illustrated in  FIGS. 1 and 3 , when the WAKE caution is initiated, one or more of the visual display screen  110  and the annunciator  112  of the output device  108  will visually and/or audibly indicate the wake advisory, respectively. 
         [0023]    The avionic wake turbulence awareness system  100  may receive ADS-B transmissions from multiple aircraft within the vicinity of the equipped aircraft. It is possible that more than one of these multiple aircraft may have a flight path history that indicates that there is a potential wake turbulence risk to the equipped aircraft. In an aspect of the present invention, the controller  104  may utilize a prioritization scheme that is capable of determining among the flight path histories of the multiple other aircraft, which of the multiple other aircraft creates a greatest risk of the equipped aircraft encountering the potential wake turbulence of that aircraft. The controller  104  may then provide guidance to the pilot of the equipped aircraft to avoid a potential encounter with the highest risk potential wake turbulence. Thus, the visual indication  306  may be displayed at only one aircraft depiction, and the distance  302  and time of separation  304  for only that intruding aircraft, even though multiple aircraft depictions may be displayed on the display screen  110 . This prioritization scheme avoids the pilot needing to make a choice as to which intruding aircraft needs to be avoided in order to take the least risky route. 
         [0024]    In an aspect of the present invention, the avionic wake turbulence awareness system  100  may utilize a hierarchy to prioritize advisories, select a highest threat intruder, and suppress advisories for much smaller aircraft that would not create a significant wake vortex/turbulence as compared to the equipped aircraft. The tables below (Tables I &amp; II) are an exemplary aircraft assignment for a six category system, as proposed by the Federal Aviation Administration (FAA). The list is not all-inclusive. As illustrated in Table I, aircraft models are categorized according to size, from Category A (the largest) to Category F (the smallest). Table II illustrates how the necessary separation between aircraft can vary according to the varying sizes of the leader aircraft and the follower aircraft. The minimum separation increases with the size ratio between the leading aircraft and the trailing aircraft. The minimum radar separation (MRS) is a variable minimum horizontal separation required between radar controlled aircraft, based upon their range from the controlling radar. For example, the MRS may be 3-8 nautical miles. The minimum required separation may be greater than the MRS, such as when the following aircraft type is smaller than the leading aircraft type. 
         [0000]    
       
         
               
               
               
               
               
               
             
           
               
                 TABLE I 
               
               
                   
               
               
                 Category A 
                 Category B 
                 Category C 
                 Category D 
                 Category E 
                 Category F 
               
               
                   
               
             
             
               
                 A380 
                 B747 series 
                 MD11 
                 B757 series 
                 AT72 
                 E120 
               
               
                 AN-225 
                 A340 series 
                 B767 
                 B737 series 
                 RJ100 
                 B190 
               
               
                 End of list 
                 B777 series 
                 A306 
                 A320 series 
                 RJ85 
                 C650 
               
               
                   
                 A330 series 
                 A310 
                 B727 series 
                 B463 
                 H25B 
               
               
                   
                 B787 series 
                 DC8 
                 MD80 series 
                 B462 
                 C525 
               
               
                   
                 C-5 
                 DC10 
                 F50 
                 E170 
                 GA multi- 
               
               
                   
                   
                   
                   
                   
                 engine aircraft 
               
               
                   
                 B-52 
                 C-17 
                 E190 
                 CRJ1/2 
                 GA single 
               
               
                   
                   
                   
                   
                   
                 engine aircraft 
               
               
                   
                 IL-96 
                 C-135 
                 B717 
                 CRJ7/9 
               
               
                   
                   
                 B-1 
                 GLF5 
                 AT45 
               
               
                   
                   
                 B-2 
                 DC95 
                 AT43 
               
               
                   
                   
                   
                 DC93 
                 GLF4 
               
               
                   
                   
                   
                 DH8D 
                 SF34 
               
               
                   
                   
                   
                 F100 
                 DH8A/B/C 
               
               
                   
                   
                   
                 F70 
                 E135/145 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE II 
               
             
             
               
                   
                   
               
               
                   
                 Follower (Nautical Mile) 
               
             
          
           
               
                   
                 A 
                 B 
                 C 
                 D 
                 E 
                 F 
               
               
                   
                   
               
             
          
           
               
                 Leader 
                 A 
                 MRS 
                 5 
                 6 
                 7 
                 7 
                 8 
               
               
                   
                 B 
                 MRS 
                 3 
                 4 
                 5 
                 5 
                 7 
               
               
                   
                 C 
                 MRS 
                 MRS 
                 MRS 
                 3.5 
                 3.5 
                 6 
               
               
                   
                 D 
                 MRS 
                 MRS 
                 MRS 
                 MRS 
                 MRS 
                 5 
               
               
                   
                 E 
                 MRS 
                 MRS 
                 MRS 
                 MRS 
                 MRS 
                 4 
               
               
                   
                 F 
                 MRS 
                 MRS 
                 MRS 
                 MRS 
                 MRS 
                 MRS 
               
               
                   
               
               
                 NOTE: 
               
               
                 MRS: Minimum Radar Separation. 
               
             
          
         
       
     
         [0025]      FIGS. 5A and 5B  illustrate exemplary wake turbulence caution areas  502  and how the dimensions of the wake turbulence caution area  502  are defined by the type of intruder/leading aircraft and related information. As illustrated in  FIG. 5A , an exemplary wake turbulence caution area  502  may be three minutes in length, based upon the ground speed of the intruder/leading aircraft. The exemplary wake caution area&#39;s vertical dimension, extending below the altitude of the intruder/leading aircraft, may be a notional 1000 feet for category A-D types, and a notional 600 feet for category E &amp; F types. As illustrated in  FIG. 5A , the wake caution area  502  extends below the intruder/leading aircraft because a wake turbulence may drift down over time. As illustrated in  FIG. 5B , the wake turbulence caution area&#39;s exemplary width may also vary according to category type. For example, the width may also be a notional 1000 feet for category A-D types, and a notional 600 feet for category E &amp; F types. As noted herein, the exemplary length, width, and height values are notional, and other dimensions based on category types are anticipated. 
         [0026]      FIGS. 6A and 6B  illustrate exemplary wake turbulence caution areas  502  that are shaped to follow the flight path histories  602  of the intruder/leading aircraft. In other words, a wake turbulence caution area&#39;s dimensions will conform to the path of a flight path history as it moves in three dimensions. 
         [0027]    Thus, embodiments of the present invention are capable of improving safety by providing quantitative separation information for a flight operation that is typically performed visually using the pilot&#39;s judgement. In addition, the system provides awareness to a developing or potential wake turbulence encounter that may not be readily apparent to the pilot, such as crossing flight paths that may occur during any phase of the flight. This may be accomplished because the flight paths of both aircraft may be known from the controller  104  that is responsive to the ADS-B receiver  102 . 
         [0028]    While the foregoing description describes several embodiments of the present invention, it will be understood by those skilled in the art that variations and modifications to these embodiments may be made without departing from the spirit and scope of the invention, as defined in the claims below. The present invention encompasses all combinations of various embodiments or aspects of the invention described herein. It is understood that any and all embodiments of the present invention may be taken in conjunction with any other embodiment to describe additional embodiments of the present invention. Furthermore, any elements of an embodiment may be combined with any and all other elements of any of the embodiments to describe additional embodiments.