Abstract:
Systems and methods for improving situational awareness on an in-trails procedures display. A radar system transmits a radar signal and receives and stores weather radar reflectivity values into a three-dimensional buffer. A processor determines whether any of the stored weather reflectivity values indicate the presence of a weather hazard and generates one or more weather hazard icons based on the stored weather reflectivity values. An in-trail procedures display device displays the generated weather hazard icons. Wake vortex information for other aircraft is generated and outputted on the in-trail procedures display. Also, the processor receives a request for an altitude change and generates an alert when the aircraft is determined not to be cleared to transition to the requested altitude based on a projected transition, any existing weather hazards, wake vortices of proximate aircraft, and in-trail procedures.

Description:
GOVERNMENT INTEREST 
       [0001]    The invention described herein was made in the performance of work under U.S. Government Contract No. DTFAWA-09-1-0001, Mod 003/Effective Sep. 14, 2009 with the FAA. The Government may have rights to portions of this invention. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Efficient oceanic operations normally require flight level changes. Climbs or descents provide optimal performance to take advantage of favorable winds or to avoid turbulence. 
         [0003]    Current oceanic operations limit opportunities for flight level changes for a number of reasons:
       Flights operate along same routes at about the same time (locally dense traffic);   Reduced surveillance performance (compared with radar) results in large separation minima for safe procedural separation.       
 
         [0006]    Automatic dependent surveillance-broadcast (ADS-B) in-trail procedures (ITP) are airborne ADS-B enabled climbs and descents through otherwise blocked flight levels. ITP is based on an approved International Civil Aviation Organization (ICAO) procedure whereby a controller separates aircraft based on information derived from cockpit sources that is relayed by the flight crew. 
         [0007]    ITP allows a leading or following aircraft on the same track to climb or descend to a desired flight level through flight levels occupied by other aircraft. An ITP display enables a flight crew to determine if specific criteria for an ITP are met with respect to one or two reference aircraft at intervening flight levels. These criteria ensure that the spacing between the estimated positions of the ITP aircraft and reference aircraft always exceeds the ITP separation minimum of 10 NM, while vertical separation does not exist during the climb or descent. Once the flight crew has established that the ITP criteria are met, they request an ITP climb or descent, identifying any reference aircraft in the clearance request. Air Traffic Control (ATC) must determine if standard separation will be met for all aircraft at the requested flight level—and at all flight levels between the initial flight level and requested flight level. If so, a standard (non-ITP) flight level change clearance is likely to be granted. Otherwise, if the reference aircraft are the only blocking aircraft, the controller evaluates the ITP request. ATC determines if the reference aircraft have been cleared to change speed or change flight level, or are about to reach a point at which a significant change of track will occur. The controller also ensures that the requesting aircraft is not referenced in another procedure. ATC also ensures that the positive Mach difference with the reference aircraft is no greater than 0.06 Mach. If each of these criteria are satisfied, then ATC may issue the ITP flight level change clearance. 
         [0008]    An example of an ITP climb is shown in  FIGS. 1 and 2 . An ITP aircraft is behind a reference aircraft that is at a higher intervening flight level (FL 350 ). Standard air traffic control (ATC) procedures apply to the other aircraft (two aircraft at FL 360  and one at FL 350 ). 
         [0009]    ITP requires new airborne equipment to provide improved information about nearby traffic. ADS-B data broadcast from these aircraft provide more accurate position data than currently available to oceanic controllers. The more accurate airborne surveillance data facilitate safe flight level changes through intervening flight levels. The airborne ITP system receives ADS-B data that includes flight identification, altitude, aircraft position, groundspeed and quality-of-data information. The ITP system displays the information derived from received ADS-B data on traffic displays such as a cockpit display of traffic information (CDTI). Both plan-view and vertical situational awareness displays (VSAD) are possible, see  FIG. 3 . 
       SUMMARY OF THE INVENTION 
       [0010]    The present invention provides systems and methods for improving situational awareness on an in-trail procedures display. A radar system transmits a radar signal and receives and stores weather radar reflectivity values into a three-dimensional buffer. An example processor determines whether any of the stored weather reflectivity values indicate the presence of a weather hazard and generates one or more weather hazard icons based on the stored weather reflectivity values. An in-trail procedures display device displays the generated weather reflectivity and weather hazard icons. Wake vortex information for other aircraft is generated and outputted on the in-trail procedures display. Also, the processor receives a request for an altitude change and generates an alert when the aircraft is determined not to be cleared to transition to the requested altitude based on a projected transition, any existing weather hazards, wake vortices of proximate aircraft, and in-trail procedures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    Preferred and alternative embodiments of the present invention are described in detail below with reference to the following drawings: 
           [0012]      FIGS. 1 and 2  illustrate side views of an aircraft performing altitude changes during oceanic flight operations; 
           [0013]      FIG. 3  illustrates an in-trail processing (ITP) display formed in accordance with the prior art; 
           [0014]      FIG. 4  illustrates a schematic diagram of a system formed in accordance with an embodiment of the present invention; 
           [0015]      FIGS. 5 and 6  illustrate ITP displays showing functionality according to embodiments of the present invention; 
           [0016]      FIG. 7-1  illustrates a partial ITP display showing wake vortex functionality; 
           [0017]      FIG. 7-2  illustrates a wake vortex icon generated in accordance with an embodiment of the present invention; and 
           [0018]      FIG. 8  illustrates various winds-aloft icons. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]      FIG. 4  illustrates an embodiment of a system for providing improved in-trail procedures (ITP) functionality on an aircraft  20 . The exemplary system includes a weather radar system  40 , a processor  42 , memory  43 , an ITP display device  44 , a data-link (e.g., ADS-B)  45 , a user interface  48 , and a memory  43 , and other aircraft systems  46 . An example of the radar system  40  includes a radar controller  50 , a transmitter  52 , a receiver  54 , and an antenna  56 . The radar controller  50  controls the transmitter  52  and the receiver  54  for performing the sending and receiving of signals through the antenna  56 . The weather radar system  40  and the processor  42  are in signal communication with the aircraft systems  46 . 
         [0020]    Radar relies on a transmission of a pulse of electromagnetic energy, referred to herein as a signal. The antenna  56  narrowly focuses the transmission of the signal pulse in comparison with the whole breadth of a desired downrange image. Like the light from a flashlight, this narrow signal illuminates any objects (target  60 ) in its path and illuminated objects reflect the electromagnetic energy back to the antenna. 
         [0021]    Reflectivity data corresponds to that portion of a radar&#39;s signal reflected back to the radar by liquids (e.g., rain) and/or frozen droplets (e.g., hail, sleet, and/or snow) residing in a weather object, such as a cloud or storm, or residing in areas proximate to the cloud or storm generating the liquids and/or frozen droplets. 
         [0022]    The radar controller  50  or another processor calculates the distance of the weather object relative to the antenna  56 , based upon the length of time the transmitted signal pulse takes in the transition from the antenna  56  to the target  60  and back to the antenna  56 . The relationship between distance and time is linear as the velocity of the signal is constant, approximately the speed of light in a vacuum. 
         [0023]    The memory  43  includes a three-dimensional volumetric buffer for storing the reflectivity data. The processor  42  has the capabilities of inferring lightning, hail, or turbulence based on the reflectivity values stored in the volumetric buffer. The processor  42 , having access to the volumetric buffer, provides weather and wake vortex information to the ITP display device  44 . 
         [0024]    An ITP climb or descent request generated by the ITP processor  42  includes weather information from the weather radar system  40  and wake vortex information and information about any ITP aircraft or weather based on information received via the data-link  45 . The pilot gets the additional weather information and makes an altitude change request based on that additional data if appropriate. In one embodiment, the Oceanic Air Traffic Controller (OATC) also gets this information, i.e. it is transmitted to the OATC via the ITP request. 
         [0025]    The ITP plan view, vertical situation awareness display (VSAD) and/or three-dimensional display devices  44  present all relevant data. This data includes: 
         [0026]    Airborne three-dimensional weather reflectivity data; 
         [0027]    Airborne weather hazard information, such as presence of turbulence, convective activity, hail, lightning; 
         [0028]    Predictive wake vortex information; 
         [0029]    Data-linked winds-aloft data; 
         [0030]    Data-linked weather (service provided); and 
         [0031]    Data-linked weather from other aircraft (e.g., PIREPS, temp, pressure). 
         [0032]    An example weather radar system is Honeywell&#39;s IntuVue™ Weather Radar, which encompasses a three-dimensional volumetric buffer. The radar system  40  continuously scans the entire three-dimensional space in front of the aircraft  20  and stores all reflectivity data in an earth-referenced, three-dimensional (or “volumetric”) memory buffer (memory  43 ). The buffer is continuously updated with reflectivity data from new scans. The data stored in the buffer are compensated for aircraft movement (speed, heading, altitude). The data in the buffer are updated at a rate of every 30 seconds, for example. The three-dimensional method employs a scanning scheme that provides full coverage over a total of −15 to +15 degrees tilt control range. The reflectivity data are extracted from the buffer to generate the desired display views without having to make (and wait for) view-specific antenna scans. In one embodiment, this extraction and image generation are performed at one-second intervals (compared to four seconds for conventional radar). With the three-dimensional volumetric buffer data, the display presentation is not constrained to a single tilt-plane that is inherent to conventional radar. 
         [0033]    The present invention provides weather awareness enhancements on the ITP display device  44  that include: 
         [0034]    Three-dimensional weather reflectivity data; 
         [0035]    Weather hazard information, such as the presence of turbulence, convective activity, hail, volcanic ash, lightning; 
         [0036]    Wake vortex; 
         [0037]    Winds-aloft data; 
         [0038]    Data-linked weather (from service providers); and 
         [0039]    Data-linked weather from other aircraft. 
         [0040]      FIG. 5  shows three-dimensional reflectivity data integrated on an ITP display  100  having a plan view section  102  and a vertical situation awareness (VSA) section  104 . Turbulence data is also shown. In one embodiment, the weather reflectivity data retrieved from the volumetric weather buffer are converted in the same way that the icons of other aircraft are displayed to reflect ITP position (actual range may also be used) when presented on the VSA section  104  of the ITP display  100 . In other words, the displayed location of other aircraft on the ITP display device  44  takes into account motion/convergence of the other aircraft to the flight path of the own aircraft. The motion and calculated center position of the detected weather on current track of the ownship and within a specified lateral distance is also used to adjust the associated icon&#39;s longitudinal ITP position (Or range on the alternative embodiment) on the ITP display device  44 . In another embodiment, this conversion may also be performed for the icon presented in the plan view section  102 . The detected weather condition is presented as a first icon(s)  110  in the plan view section  102  and as a second icon(s)  120  in the VSA section  104 . 
         [0041]    In another embodiment the actual range (and therefore not ITP distance) is used when weather reflectivity data are presented on the VSA section  104  of the ITP display  100 . Thus, the x-axis on the VSA section  104  could either be ITP distance or actual range. This implies that the pilot would have three possible displays (Plan View, ITP based VSA display with other aircraft, and range based VSA display with weather and with or without traffic). 
         [0042]      FIG. 6  shows lightning and hail icons included with detected and displayed weather conditions  164 ,  166  shown in a plan view and VSA sections of an ITP display  150 . An “ownship” icon  162  is shown in both sections of the ITP display  150 . 
         [0043]      FIGS. 7-1  and  7 - 2  illustrate a VSA section of an ITP display  180  that shows relevant wake vortex information based on information stored in the memory  43  and/or received from the target aircraft via the data-link  45 . A wake vortex icon  188  shows a wake vortex plume from a target aircraft icon  184  (Delta Airlines flight  818 ). The predictive driftdown path is shown, trailing distance, width, rotational velocity (R 180° S=180° of roll per second to the right). Other identifier may include C-Roll 180° sec which means clockwise roll rate of 180 deg sec and CC-Roll 180° sec which means counterclockwise roll at 180° sec. Wake turbulence is predicted from aircraft make/model, speed, altitude, and ambient conditions (i.e. ISA temperature, pressure). The ADS-B message (via the data-link device  45 ) transmits the aircraft make/model, altitude, speed, etc. The processor  42  correlates the received information with on-board stored wake turbulence predictive algorithms and generates the intuitive wake vortex icon  188  that allows the crew to quickly assess their potential for wake encounters before climbing or descending. 
         [0044]    Other icons can be presented on ITP displays. Exemplary icons show the vertical dimensions of icing, winds aloft, etc. Forecast or reported winds aloft, outside air temperature (OAT) and pressure, and ride reports (i.e., PIREPS) can all be used to inform the pilot when received, transformed, and rendered on the ITP display device  44 . Aircraft ahead of own ship data-link actual conditions, while weather service providers transmit forecast conditions as well as actual weather along the route of flight. This weather data will in some cases have to be extrapolated into a three-dimensional model, while, in other cases, the three-dimensional data will be packaged by the provider. As shown in  FIG. 8 , a winds-aloft icon may include velocity and source of information. Examples of the source of information include forecast winds (FW), data-linked winds (DL) from aircraft ahead and at same altitude, and pilot reports (PIREPS) winds (PR) that are data-linked to “ownship”. 
         [0045]    One of the key tasks for the flight crew during an ITP climb or descent is to select the desired flight level prior to detecting potentially blocking aircraft. After the crew selects a desired flight level, that flight level is highlighted on the vertical profile section of the ITP display. In one embodiment, the processor  42  provides the flight crew with a visual, aural, and/or tactile alert if the desired flight level passes through or is within predefined lateral and vertical constraints from the hazardous area. Hazards can include turbulence, hail, lightning, convective activity, volcanic ash or a wake vortex. Other hazards may include violating ITP procedure if the altitude change is executed. The visual alert is provided on the VSAD section of the ITP display, plan-view and/or three-dimensional display.  FIG. 7-1  shows wake vortex and altitude transition alerts on the ITP display  180 . The desired flight level ( 350 ) passes through a hazardous area (wake vortex) and thus the flight level is visually coded (e.g., flashing and/or differently colored (e.g., amber)). An audio and/or visual text message “check desired flight level” can also be presented. 
         [0046]    A menu system can be provided (via the user interface  48 ) to the pilot so that the pilot is able to select or declutter just those weather objects of interest and that are relevant to the crew&#39;s decision making Alerting can be provided to the crew to make it obvious that desired flight level or track change may take the aircraft into an area of hazardous weather. In another embodiment, an options allows the crew to select ITP distance or actual range based displays. 
         [0047]    While the preferred embodiment of the invention has 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 the preferred embodiment. Instead, the invention should be determined entirely by reference to the claims that follow.