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Claims  |
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What is claimed:
1. A system for providing a retrievable record of the flight performance of an aircraft comprising:
a ground data link unit that obtains flight performance data representative of aircraft flight performance during flight of the aircraft, said ground data link unit comprising:
a) an archival data store operative to accumulate and store flight performance data during flight of the aircraft, and
b) a wideband spread spectrum transceiver coupled to said archival data store, and comprising a transmitter that is operative after the aircraft completes its flight and lands at an airport to download the flight performance data that has been
accumulated and stored by said archival data store during flight over a wideband spread spectrum communication signal that comprises a signal in the range of about 2.4 to about 2.5 GHz;
an airport based wideband spread spectrum transceiver comprising a receiver that receives the wideband spread spectrum communication signal from the aircraft and demodulates the signal to obtain the flight performance data;
an airport based archival data store coupled to said airport based wideband spread spectrum transceiver that receives and stores the demodulated flight performance data;
an airport based processor coupled to said archival data store for retrieving flight data performance from the airport based archival data store;
a remote flight operations control center; and
an airport based communications network operatively connecting said remote flight operations control center and airport based processor to allow the remote flight operations control center to receive and analyze the flight performance data.
2. A system according to claim 1, wherein said remote flight operations control center further comprises a system controller and plurality of ground data link workstations operatively connected to said system controller to allow flight
performance analysts to evaluate aircraft flight performance data.
3. A system according to claim 1, wherein the wideband spread spectrum communication signal comprises a direct sequence spread spectrum signal.
4. A system according to claim 1, wherein the wideband spread spectrum communication signal comprises a signal within the S band.
5. A system according to claim 1, wherein said airport based wideband spread spectrum transceiver further comprises a wireless router that couples said wideband spread spectrum transceiver to said airport based archival data store.
6. A system according to claim 1, wherein said archival data store of said ground data link unit further comprises means for compressing said flight performance data during the flight of the aircraft.
7. A system according to claim 1, and further comprising a flight data recording system positioned on board the aircraft, wherein said archival data store of said ground data link unit is operatively coupled to said flight data recording system.
8. A system for providing a retrievable record of the flight performance of an aircraft comprising:
a ground data link unit that obtains flight performance data representative of aircraft flight performance during flight of the aircraft, said ground data link unit comprising:
a) an archival data store operative to accumulate and store flight performance data during said flight of said aircraft, and
b) a wideband spread spectrum transceiver coupled to said archival data store, and comprising a transmitter that is operative after the aircraft completes its flight and lands at an aircraft to download said flight performance data that has been
accumulated and stored by said archival data store during flight over a wideband spread spectrum communication signal that comprises a signal in the range of about 2.4 to about 2.5 GHz;
a plurality of airport based wideband spread spectrum transceivers, each comprising a receiver that receives the wideband spread spectrum communications signal from the aircraft and demodulates the signal to obtain the flight performance data;
an airport based local area network connected to said plurality of airport based spread spectrum transceivers;
at least one airport base station operatively connected to said plurality of airport based wideband spread spectrum transceivers through said airport based local area network, said base station further comprising,
an archival data store that receives and stores said flight performance data; and
a processor coupled to said archival data store for retrieving flight data performance from the archival data store;
a remote flight operations control center; and
an airport based communications network operatively connecting said remote flight operations control center and base station for requesting downloading of said flight performance data from said processor and archival data storage for transmission
along said airport based communications network to said remote flight operations control center.
9. A system according to claim 8, wherein said airport based communications network connects said remote flight operations control center to other airport based base stations located at other airports to receive and analyze flight performance
data from those airports.
10. A system according to claim 8, wherein said flight operations control center further comprises a system controller and plurality of ground data link workstations operatively connected to said system controller to allow flight performance
analysts to evaluate aircraft flight performance data.
11. A system according to claim 8, wherein the wideband spread spectrum communication signal comprises a direct sequence spread spectrum signal.
12. A system according to claim 8, wherein the wideband spread spectrum communication signal comprises a signal within the S band.
13. A system according to claim 8, wherein said airport based wideband spread spectrum transceiver further comprises a wireless router that couples said wideband spread spectrum transceiver to said airport based base station.
14. A system according to claim 8, wherein said archival data store of said ground data link unit further comprises means for compressing said flight performance data during the flight of the aircraft.
15. A system according to claim 8, wherein said transceivers operate in half duplex mode.
16. A system for exchanging information to and from an aircraft comprising:
a ground data link unit that obtains flight performance data representative of aircraft flight performance during flight of the aircraft, said ground data link unit comprising:
a) an archival data store operative to accumulate and store flight performance data during said flight of said aircraft, and
b) a wideband spread spectrum transceiver coupled to said archival data store, and comprising a transmitter that is operative after the aircraft completes its flight and lands at an airport to download said flight performance data that has been
accumulated and stored by said archival data store during said flight, over a first wideband spread spectrum communication signal that comprises a signal in the range of about 2.4 to about 2.5 GHz, and a receiver for receiving uploaded data over a second
wideband spread spectrum communication signal that comprises a signal in the range of about 2.4 to about 2.5 GHz;
an airport based wideband spread spectrum transceiver comprising a receiver that receives the first wideband spread spectrum communication signal from the aircraft and demodulates the signal to obtain the flight performance data, and a
transmitter that transmits data for uploading to the aircraft over a second wideband spread spectrum communication signal, said unloaded data including video, audio and flight information;
an airport based archival data store coupled to said airport based wideband spread spectrum transceiver that receives and stores said flight performance data and data to be uploaded to said aircraft;
an airport based processor coupled to said archival data store for retrieving flight performance data from the airport based archival data store; and
a remote flight operations control center operatively coupled to said airport based processor to receive and analyze the flight performance data, said remote flight operations control center also storing video, audio and flight information for
unloading.
17. A system according to claim 16, and further comprising a communications network interconnecting said airport based processor and said remote flight operations control center.
18. A system according to claim 17, wherein said communications network further comprises a local public switched telephone network.
19. A system according to claim 16, wherein said flight operations control center further comprises a system controller and plurality of ground data link workstations operatively connected to said system controller to allow flight performance
analysts to evaluate aircraft flight performance data.
20. A system according to claim 16, wherein said video, audio and flight information to be uploaded to said aircraft further comprises digitized in-flight passenger service and entertainment video and audio files.
21. A system according to claim 16, wherein the wideband spread spectrum communication signal comprises a direct sequence spread spectrum signal.
22. A system according to claim 16, wherein the wideband spread spectrum communication signal comprises a signal within the S band.
23. A system according to claim 16, wherein said uploaded data comprises flight navigation information, and digitized in-flight passenger service and entertainment video and files.
24. A system according to claim 16, wherein said airport based wideband spread spectrum transceiver further comprises a wireless router that couples said wideband spread spectrum transceiver to said airport based archival data store.
25. A system according to claim 16, wherein said airchival data store of said ground data link unit further comprises means for compressing said flight performance data during the flight of the aircraft.
26. A system according to claim 16, wherein said transceivers operate in half duplex mode.
27. A method of providing a retrievable record of the flight performance of an aircraft comprising the steps of:
collecting data within a ground data link unit on the flight performance of the aircraft during flight of the aircraft;
accumulating and storing within an archival data store of the ground data link unit the flight performance data during flight of the aircraft;
after the aircraft lands at an airport at completion of the flight, downloading the flight performance data that has been accumulated and stored during the flight over a wideband spread spectrum communication signal that comprises a signal in the
range of about 2.4 to about 2.5 GHz to an airport based spread spectrum receiver;
demodulating within the receiver the received spread spectrum signal to obtain the flight performance data;
storing the demodulated flight performance data within an airport based archival data store; and
retrieving the flight performance data via an airport based processor; and
routing the flight performance data from the airport based processor and archival data store via a first around based wideband spread spectrum transceiver via a first wideband spread spectrum communication signal to a ground based wideband spread
spectrum transceiver functioning as a repeater to relay the flight performance data to a remote flight operations control center via a second wideband spread spectrum communication signal.
28. A method according to claim 27, and further comprising the step of evaluating the flight performance data at a plurality of ground data link workstations within the remote flight operations center.
29. A method according to claim 27, wherein the wideband spread spectrum communication signal comprises a direct sequence spread spectrum signal.
30. A method according to claim 27, wherein the wideband spread spectrum communication signal comprises a signal within the S band.
31. A method according to claim 27, wherein the wideband spread spectrum communication signal comprises a signal within the range of about 2.4 to about 2.5 Ghz.
32. A method according to claim 27, and further comprising the step of compressing the flight perfomance data within the archival memory storage during flight of the aircraft.
33. A method of exchanging data to and from an aircraft comprising the steps of:
collecting data within a ground data link unit on the flight performance of the aircraft during flight of the aircraft;
accumulating and storing within an archival data store of the ground data link unit the flight performance data during flight of the aircraft;
after the aircraft lands at an airport at completion of the flight, downloading the flight performance data that has been accumulated and stored during the flight over a first wideband spread spectrum communication signal that comprises a signal
within the range of about 2.4 to about 2.5 GHz to an airport based spread spectrum transceiver;
demodulating the received spread spectrum signal within the airport based spread to obtain the flight performance data;
storing the demodulated flight performance data within an airport based archival data store;
retrieving data to be uploaded from a remote flight operations control center and forwarding the data to be uploaded to the airport based archival data storage;
retrieving the data to be uploaded from the airport based archival data storage; and
transmitting the data from an airport based spread spectrum transceiver to the aircraft along a second wideband spread spectrum communication signal that comprises a signal within the range of about 2.4 to about 2.5 GHz to the ground data link
unit within the aircraft.
34. A method according to claim 33, and further comprising the step of evaluating the flight performance data at a plurality of ground data link workstations within the remote flight operations center.
35. A method according to claim 33, wherein the wideband spread spectrum communication signal comprises a direct sequence spread spectrum signal.
36. A method according to claim 33, wherein the wideband spread spectrum communication signal comprises a signal within the S band.
37. A method according to claim 33, and further comprising the step of uploading to the aircraft from the airport based spread spectrum transceiver video, audio and flight information that has been stored within the airport based archival data
store.
38. A method according to claim 37, wherein the video, audio and flight information to be uploaded further comprises digitized in-flight passenger service and entertainment video and audio files. |
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Claims |
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Description |
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FIELD OF THE INVENTION
The present invention relates in general to communication systems, and is particularly directed to an aircraft data communication system having a plurality of wireless ground links that link respective aircraft-resident subsystems, in each of
which a copy of its flight performance data is stored, with airport-located ground subsystems, each ground subsystem being coupled, in turn, by way of respective telco links to a remote flight operations control center, where flight performance data from
plural aircraft parked at different airports may be analyzed and from which the uploading of in-flight data files may be directed by airline systems personnel.
BACKGROUND OF THE INVENTION
Modern aircraft currently operated by the commercial airline industry employ airborne data acquisition (ADA) equipment, such as a digital flight data acquisition unit (DFDAU) as a non-limiting example, which monitor signals supplied from a
variety of transducers distributed throughout the aircraft, and provide digital data representative of the aircraft's flight performance based upon such transducer inputs. As flight performance data is obtained by the acquisition equipment, it is stored
in an attendant, physically robust, flight data recorder (commonly known as the aircraft's "black box"), so that in the unlikely event of an in-flight mishap, the flight data recorder can be removed and the stored flight performance data analyzed to
determine the cause of the anomaly.
In a further effort to improve aircraft safety, rather than wait for an accident to happen before analyzing flight recorder data, the Federal Aviation Administration (FAA) has issued a draft advisory circular AC-120-XX, dated Sep. 20, 1995,
entitled "Flight Operational Quality Assurance Program" (FOQA), which recommends that the airlines look at the information provided by the digital flight data acquisition unit at regular intervals.
One suggested response to this recommendation is to equip each aircraft with a redundant flight data recording unit having a removable data storage medium, such as a floppy disc. Such an auxiliary digital data recorder is intended to allow
aircraft safety personnel to gain access to the flight performance data by physically removing the auxiliary unit's data disc, the contents of which can then be input to an aircraft performance analysis data processing system for evaluation.
Although installing such a redundant flight data recording unit allows airline personnel to retrieve a copy of the flight performance data for subsequent evaluation, when considering the large volume of aircraft traffic experienced by major
commercial airports, the above-proposed scheme is not only extremely time and manpower intensive, but is prone to substantial misidentification and aircraft/data association errors.
Other proposals, described in U.S. Pat. No. 5,359,446, are to use either a direct line-of-sight infrared link or a fiber optic cable to couple an on-board aircraft computer system with a ground-based computer system. Obvious drawbacks to these
systems are the fact that not only do they employ complex and expensive components, but require that the aircraft be parked at the gate, so that the line-of-sight infrared transceivers or the fiber optic connection assemblies can be properly interlinked. As a consequence, neither of these types of systems is effective for use with commuter, cargo or military aircraft, which are customarily parked on an apron, rather than at a mating jetway, where such an optical link is to be provided.
SUMMARY OF THE INVENTION
In accordance with the present invention, the above-described objective of periodically analyzing flight performance data, without having to physically access a redundant unit on board the aircraft, is successfully addressed by means of a
wireless ground data link, through which flight performance data provided by airborne data acquisition equipment is stored, compressed, encrypted and downloaded to an airport-resident ground subsystem, which forwards flight performance data files from
various aircraft to a flight operations control center for analysis. For purposes
of providing a non-limiting example, in the description of the present invention, the data acquisition equipment will be understood to be a DFDAU.
For this purpose, an auxiliary data path is coupled from the DFDAU in parallel with the flight data recorder to a bidirectional radio frequency (RF) carrier-based ground data link (GDL) unit, that is installed in the avionics compartment of the
aircraft. The GDL unit is operative to communicate with an airport-resident ground subsystem via the RF communications ground link infrastructure.
In accordance with a preferred embodiment of the invention, this wireless ground data link is implemented as a spread spectrum RF link, preferably having a carrier frequency lying in a reasonably wide (on the order of 100 MHz) unlicensed 2.4-2.5
GHz S-band segment, which provides the advantage of global acceptance. A benefit of spread spectrum modulation is its inherently low energy density waveform properties, which are the basis for its acceptance for unlicensed product certification. Spread
spectrum also provides the additional benefits of resistance to jamming and immunity to multipath interference.
A principal function of the GDL unit is to store a compressed copy of the (ARINC 717) flight performance data generated by the DFDAU and supplied to the aircraft's flight data recorder. The GDL unit is also configured to store and distribute
auxiliary information uploaded to the aircraft from a wireless router (as directed by the remote operations control center) in preparation for its next flight. The uploaded information may include audio, video and data, such as flight navigation
information, and digitized video and audio files that may be employed as part of an in-flight passenger service/entertainment package. The GDL unit may also be coupled to an auxiliary printer that is ported to the GDL unit in order to enable an
immediate hard copy of flight data information (e.g. exceedences of parameter data) to be provided to the crew immediately upon the conclusion of the flight.
Once an aircraft has landed and is within communication range of the ground subsystem, the wireless router receives flight performance data via the wireless ground data link from an aircraft's GDL unit. It also supplies information to the
aircraft in preparation for its next flight. The wireless router receives flight files from the aircraft's GDL unit and forwards the files to an airport base station, which resides on the airports local area network (LAN).
The airport base station forwards flight performance data files from various aircraft by way of a separate communications path such as a telephone company (telco) land line to a remote flight operations control center for analysis. The airport
base station automatically forwards flight summary reports, and forwards raw flight data files, when requested by a GDL workstation.
The flight operations control center, which supports a variety of airline operations including flight operations, flight safety, engineering and maintenance and passenger services, includes a system controller segment and a plurality of FOQA
workstations through which flight performance system analysts evaluate the aircraft data files that have been conveyed to the control center.
Depending upon its size and geographical topography, an airport may include one or more wireless routers, that are installed within terminal buildings serving associated pluralities of gates, to ensure complete gate coverage. Redundant base
stations may be utilized to assure high system availability in the event of a hardware failure. A large commercial airport exhibits the communication environment of a small city; consequently, it can be expected that radio communications between a
respective wireless router and associated aircraft at gates will be subjected to multipath interference. In order to prevent the disruption of wireless router-GDL communications as a result of such a multipath environment, the wireless ground data link
between each aircraft and a wireless router is equipped to execute either or both of a frequency management and an antenna diversity scheme.
Antenna diversity, which may involve one or more diversity mechanisms, such as spatial or polarization diversity, ensures that an aircraft that happens to be in a multi-path null of one antenna can still be in communication with another antenna,
thereby providing full system coverage regardless of blockage. Frequency management is accomplished by subdividing a prescribed portion of the unlicensed radio frequency spectrum used by the system for GDL--wireless router communications into adjacent
sub-band channels, and dynamically assigning such sub-band channels based upon the quality of the available channel links between a respective wireless router and a given aircraft. Such sub-channel assignments may involve downloading compressed and
encrypted aircraft flight data over a first channel portion of the usable spectrum to the wireless router, and uploading information from a base station to the aircraft (e.g. video, audio and flight control data) from a wireless router over a second
channel portion of the useable spectrum to the GDL on board the aircraft.
In a preferred embodiment, a respective wireless router employs a source coding system that achieves bandwidth reduction necessary to permit either multiple audio channels to be multiplexed onto the wireless transmit carrier to the GDL unit,
video to be transmitted over a ground subsystem's wireless router-to-GDL unit ground link frequency channel, or data files to be compressed to maximize system throughput and capacity during communications (uploads to or downloads from) the aircraft.
Cyclic Redundancy Check (CRC) coding is used for error detection only. When errors are detected at the wireless router, its transceiver requests a retransmission from the GDL unit, in order to guarantee that the copy of the flight performance
data file downloaded from the GDL unit and forwarded from a wireless router is effectively error free.
In the uplink direction from the ground subsystem to the aircraft, the bit error rate requirements for transmitting passenger entertainment audio and video files are less stringent, and a forward error correction (FEC) and error concealment
mechanism is sufficient to achieve a playback quality acceptable to the human audio/visual system. Also since uploading an in-flight passenger audio/video file, such as a news service or entertainment program, may entail several tens of minutes
(customarily carried out early in the morning prior to the beginning of airport flight operations), there is usually no additional time for its retransmission.
The wireless router transceiver includes a control processor which ensures robust system performance in the dynamically changing unlicensed spread spectrum interference environment of the ground data link by making decisions based on link signal
quality, for the purpose of setting transmit power level, channel frequency assignment, and antenna selection. The ground subsystem processor also initiates a retransmission request to an aircraft's GDL unit upon detection of a bit error in a downlinked
flight performance data packet.
Before requesting retransmission of a flight data packet, the wireless router's transceiver measures the signal quality on the downlink channel portion of the ground data link. The transceiver in the wireless router assesses the measured link
quality, increases its transmit power level as necessary, and requests a retransmission of the packet containing the bit error at a higher transmit power level. It then initiates a prescribed frequency management protocol, to determine if another
channel portion of the GDL link would be a better choice. If a higher quality channel is available, both transceivers switch over to the new frequency. The flight performance data packet containing the bit error is retransmitted until it is received
error free at the wireless router.
Because the invention operates in an unlicensed portion of the electromagnetic spectrum, it can be expected to encounter other unlicensed communication products, such as employed by curbside baggage handling and ticketing, rental car and hotel
services, etc., thereby making the communication environment unpredictable and dynamically changing. To solve this problem, the present invention employs a frequency management scheme, which initially determines the optimum operating frequency and
automatically changes to a better quality frequency channel when the currently established channel suffers an impairment.
The spread spectrum transceiver in each of an aircraft's GDL unit and an associated airport wireless router includes a frequency agile spread spectrum transmitter, a frequency agile spread spectrum receiver and a frequency synthesizer. In
addition to being coupled to an associated control processor, the spread spectrum transmitter is coupled to an adaptive power control unit and an antenna diversity unit. Such a power allocation mechanism makes more efficient use of available power
sources, reduces interference, and makes more efficient use of the allocated frequency spectrum. The control processors at each end of the wireless ground link execute a communication start-up protocol, through which they sequentially evaluate all of
the available frequency channels in the unlicensed 2.4-2.5 GHz S-band segment of interest and assess the link quality of each of these channels.
Each wireless router transceiver sequentially and repeatedly sends out a probe message directed to any of the GDL units that are within the communication range of gates served by that wireless router, on each of all possible frequency channels
into which the 2.4-2.5 GHz S-band spread spectrum bandwidth has been divided. Each GDL unit within communication range of the wireless router returns a response message on each frequency channel, and indicates which frequency is preferred, based upon
the signal quality assessment and measured signal quality by its communication processor. The wireless router control processor evaluates the responses from each of the GDL units, selects the frequency of choice, and then notifies the GDL units within
communication range of its decision. This process is periodically repeated and is executed automatically in the event of a retransmission request from a GDL unit.
As described earlier, in an environment such as a large commercial airport, a common cause of reduced signal quality is multipath interference resulting from sudden attenuation in the direct path between the transmitters and the receivers in the
wireless router and aircraft, in conjunction with a delayed signal arriving at the receiver from a reflected path. This sudden attenuation in the direct path between the aircraft and the wireless router can result in the destructive summation of
multiple paths at the antenna in use, resulting in a severe signal fading condition. The nature of multipath is such that switching to a second spatially separated or orthogonally polarized antenna can result in a significant improvement in link
performance. Since the wireless networking environment of an airport is one in which objects are likely to be moving between the wireless router and the aircraft, and one of the platforms (the aircraft) is mobile, antenna diversity can make the
difference between reliable and unreliable system performance.
Pursuant to the invention, upon the occurrence of a prescribed reduction in link quality, an antenna diversity mechanism is employed. Such a mechanism may involve the use of separate transceivers (each having a respective antenna), or an antenna
diversity unit that switches between a pair of spatially separated or orthogonally polarized antennas. Link performance is evaluated for each antenna in real time, on a packet-by-packet basis, to determine which antenna provides the best receive signal
quality at the wireless router.
Signal quality is continually measured at the receiver demodulator output and reported to the control processor. Should there be a sudden degradation in link signal quality, the wireless router control processor switches over to the other
antenna. If the degradation in signal quality cannot be corrected by invoking the antenna diversity mechanism, such as by switching antennas, the wireless router has the option of increasing the transmit power level at both ends of the link to
compensate for the reduction in link quality and/or execute the frequency management routine to search for a better operating channel. In the wireless router's broadcast mode, the same signal can be transmitted from both antennas in order to assure
reliable reception at all aircraft, regardless of changing multipath conditions.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 diagrammatically illustrates the overall system architecture of the wireless ground link-based aircraft data communication system according to the present invention;
FIG. 1A diagrammatically illustrates a non-limiting example of where, within the terminal topography of Atlanta's Hartsfield International Airport, various subsystem portions of the system architecture of FIG. 1 may be installed;
FIG. 1B diagrammatically illustrates a modification of FIG. 1A showing various subsystem portions of the system architecture of FIG. 1 installed within the terminal topography of Atlanta's Hartsfield International Airport;
FIG. 1C lists identifications of the subsystem components of FIGS. 1, 1A and 1B;
FIG. 2 diagrammatically illustrates a respective aircraft GDL segment of the system of FIG. 1;
FIG. 3 diagrammatically illustrates a GDL data storage and communications unit of a respective GDL segment of FIG. 2;
FIG. 4 diagrammatically illustrates the gate/terminal topography of the Dallas/Fort Worth International Airport;
FIG. 5 diagrammatically illustrates a wireless router;
FIG. 6 diagrammatically illustrates the architecture of the wireless router of FIG. 5 in greater detail;
FIG. 7 details the components of a spread spectrum transceiver; and
FIG. 8 diagrammatically illustrates a non-limiting example of a frequency channel subdivision of a spread spectrum transceiver of FIG. 7.
DETAILED DESCRIPTION
Before describing in detail the wireless ground link-based aircraft data communication system in accordance with the present invention, it should be observed that the present invention resides primarily in what is effectively a prescribed
arrangement of conventional avionics and communication circuits and associated digital signal processing components and attendant supervisory control circuitry therefor, that controls the operations of such circuits and components. Consequently, the
configuration of such circuits and components and the manner in which they are interfaced with other communication system equipment have, for the most part, been illustrated in the drawings by readily understandable block diagrams, which show only those
specific details that are pertinent to the present invention, so as not to obscure the disclosure with details which will be readily apparent to those skilled in the art having the benefit of the description herein. Thus, the block diagram illustrations
are primarily intended to show the major components of the system in a convenient functional grouping, whereby the present invention may be more readily understood.
Referring now to FIG. 1, the overall system architecture of the wireless ground link-based aircraft data communication system according to the present invention is shown as being comprised of three interlinked subsystems: 1)--an
aircraft-installed ground data link (GDL) subsystem 100; 2)--an airport-resident ground subsystem 200; and 3)--a remote flight operations control center 300. Associated with FIG. 1 are FIGS. 1A and 1B, which diagrammatically illustrate non-limiting
examples of where, within the terminal topography of Atlanta's Hartsfield International Airport, various subsystem portions of the system architecture of FIG. 1 may be installed. FIG. 1A shows overlapping antenna coverage from multiple sites, while FIG.
1B shows full antenna coverage from a single tower. The subsystem portions are identified by the abbreviations listed in FIG. 1C, and referenced below.
The aircraft-installed ground data link (GDL) subsystem 100 is comprised of a plurality of GDL airborne segments 101, each of which is installed in the controlled environment of the avionics compartment of a respectively
different aircraft. Each GDL airborne segment 101 is operative to communicate with a wireless router (WR) segment 201 of the airport-resident ground subsystem 200 through a wireless communications link 120.
The wireless router segment 201 routes the files it receives from the GDL airborne segment 101, either directly to the airport base station 202 via the wired Ethernet LAN 207, or indirectly through local area networks 207 and airport-resident
wireless bridge segments 203. In accordance with a preferred embodiment of the invention, the wireless communication link 120 is a spread spectrum radio frequency (RF) link having a carrier frequency lying in an unlicensed portion of the electromagnetic
spectrum, such as within the 2.4-2.5 GHz S-band.
As will be described, once installed in an aircraft, the data terminal equipment (DTE) 102 of a GDL segment 101 collects and stores flight performance data generated on board the aircraft during flight. It also stores and distributes information
uploaded to the aircraft via a ground subsystem's wireless router 201 (shown in detail in FIG. 5, to be described) which is coupled thereto by way of a local area network 207 from a base station segment 202 of a ground subsystem 200 in preparation for
the next flight or series of flights.
The uploaded information, which may include any of audio, video and data, typically contains next flight information data, such as a set of parameter-exceedence limits, and next flight navigation information, including, but not limited to, a
navigation database associated with the flight plan of the aircraft, as well as digitized video and audio files that may be employed as part of a passenger service/entertainment package.
The ground subsystem 200 includes a plurality of airport-resident GDL wireless router segments 201, one or more of which are distributed within the environments of the various airports served by the system. A respective airport wireless router
201 is operative to receive and forward flight performance data that is wirelessly downlinked from an aircraft's GDL unit 101 and to supply information to the aircraft in preparation for its next flight, once the aircraft has landed and is in
communication with the wireless router. Each ground subsystem wireless router 201 forwards flight files from the aircraft's GDL unit and forwards the files to a server/archive computer terminal 204 of the aircraft base station 202, which resides on the
local area network 207 of the ground subsystem 200.
The airport base station 202 is coupled via a local communications path 207, to which a remote gateway (RG) segment 206 is interfaced over a communications path 230, to a central gateway (CG) segment 306 of a remote flight operations control
center 300, where aircraft data files from various aircraft are analyzed. As a non-limiting example communications path 230 may comprise an ISDN telephone company (telco) land line, and the gateway segments may comprise standard LAN interfaces.
However, it should be observed that other communication media, such as a satellite links, for example, may be employed for ground subsystem-to-control center communications without departing from the scope of the invention.
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