CA2114755A1 - Airport surveillance system - Google Patents

Abstract

Abstract of the Disclosure An airport surveillance system for detection of aircraft or other vehicles having a sensor co-located with edge lights along taxiways, runways and other surface areas, the sensor output being coupled to a central computer system via the airport's edge light power lines. The detection system comprises infrared sensors. The output of each sensor in fed into a microprocessor within an edge light assembly and then to a power line modem for transmission to the central computer which includes a display system at the airport tower for displaying the airport and all traffic thereon.
Data from each sensor along taxiways and runways is received at the central computer system and processed to provide comprehensive vehicle tracking and control of all ground traffic on the airport.

Description

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AIRPOR~ s~Rv~I~La~cx SYSTEM
Back~round of the In~ent o~
This invention relates to an airport ground surveillance system and in particular to an apparatus and method for monitoring and controlling aircraft or o~her vehicle movement primarily on airport taxiways, runways and other surface areas.
Currently, ground control of aircraft at an airport is dons visually by the air traffic controller in the tower.
Low vi~ibility conditions ~ometimes make it impossible for the controller to see all parts of the field. Ground 1 ~urface radar can help in providing coverage during lowj visibility conditions; it plays an important part in the j ~olution of the runway incur~ion problem but cannot solve the entire problem. ~ ru~way incursion is defined as "any occurrence at an airport involving an aircraft, vehicle, y per~on, or ob~ect on the ground that creates a collision hazard or results in loss of separation with an aircraft ~ taking off, intending to take off, landing, or intending to .~ 20 land.~ The U.S. Federal Admi~istration Agency (FAA) has estimated tha~ it can only justify the cost of ground surface radar at ~i9 of the top 100 airports in the United States. However, such radar only provides location information; it cannot alert the controller to pos~ible conflicts between aircraft.

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. .~, In the prior art, an airport control and monitoring system ha~ been used to sense when an airpl~ne reaches a certain point on a taxiway and controls switching lights on and off to indicate to the pilot when he may proceed on to a j~ 5 runway. Such a system sends microwave sensor information to ~! a computer in the control tower. The computer comprise~
~oftware for controlling the airport lighting and for providing fault information on the a~rport lighting via di~plays or a control panel to an operator. Such a system is described in 3ales information provided on a Bi-;;, I directional Series 7 Transceiver (BRITEE) produced by ADB-j.~
ALNACO, Inc., A Siemens Company, of Columbus, Ohio.
However, such a system does not ~how the location of all vehicles on an airfield and i~ no~ able to detect and a~oid a po3sible vehicle incursion.
A ~ell known approach to airport surface traffic control has been the use of scanning radars operating at high frequencies such as R-band in order to obtain adequate definition and resolution. An existing airport ground traffic control equipment of that type is known in the art .;,~ , .
a~ Airport Surface Detection Equipment (ASDE). However, ~uch equipment provide~ surveillance only, no discre$e identification of aircraft on $he surface being available.
I Also there is a need for a relatively high antenna tower and a relatively large rotation antenna system thereon.

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Another approach to airport ground surveillance is a ~y~tem described in U. S. Patent No. 3,872,474, issued March 18, 1974, to Arnold M. Levine and as~igned to International Telephone and Telegraph Corporation, New York, NY, referred to as LOCAR (Localized Cable Radar~ comprise~ a ~eries of ~; small, lower powered, narrow pulses, transmitting radars having limited range and time sequenced along opposite sides .1 of a runway ramp or taxiway. In another U. S. Patent No.
;~ 4,197,536, issued on April 8, 1980, to Arnold M. Levine, an airport surface identification and control system is described for aircraft equipped with ATCRBS (Air Traffic :~ Control Radio Beacon System) and ILS (Instrument Landing . Sy~tem). However, these approaches are expensive, require I special cabling and for identification purpose~ require .; 15 expensive equip~ent to ~e included on the aircraft and other i vehicles.
~ Another approach to vehicle identification such ai j~ types of aircraft by identifying the unique characteriRtic of the "footprintl~ presented by ~he configuration of wheels ~.
unique to a particular type of vehicle iB described in U.S.
Patent No. 3,872,283, issued March 18, 1975, to Gerald R.
Smith et al. and assigned to The Cadre Corporation of Atlanta Georgia.
~ An automatic system for surveillance, guidance and .1 25 fire-fighting at airports using infrared sensors is , .,;,~ .

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described in U. S. Patent No. 4,845,629, is ued July 4, 1989 ' r; to Maria V. Z. Murga. The infrared sensors are arranged ;i along the flight lanes and their output signals are '~i processed by a computer to provide information concerning the aixcraft movements along the fligh~ lanes. Position detectors are provided for detecting the position of ~ aircraft in the taxiways and parking areas. However, such .~
system does not teach the use of edge lights alon~ the runways and taxiways along with their a~sociated wiringand ~ 10 it i8 not able to detect and avoid a possible vehicle :j incursion.
The mann0r in which the invention deals with the '~ disadvantages of the prior art to provide a low cost airport ~, surveillance system, will be evident as the description S.~J 15 proceeds.
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Summar~ of the Invention Accordingly, it i8 therefore an ob~ect of this I invention to provide an airport surveillance system for : detecting and monitoring all ground traffic on runways and taxiways and other surface areas.
. It is al~o an ob~ect of this invention to provide a low J, cost airport ~urveillance system using edge light asse~blies . and associated wiring along runways and taxiways.
It is another ob~ect of thi~ invention to provide a low ~i ;~ 10 cost airport s~rvelllance sy3tem comprising infrared : detectors. `
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`I It i8 a further object of this invention to provide an .~, .
.~ airport ~urveillance system that generates a graphic display of the airport showing the location of all ground traffic including direction and velocity data.
The ob~ects are further accomplished by providing an airport surveillance system comprising a plurality of light circuits on an airport, each of the light circuits comprises . a plurality of ligh~ assembly means, means for providing power to each of the plurality of light circuits and to each of the light assembly means, means in each of the light assembly means for sensing ground traffic on the airport, means for processing da~a received from each of the light ;`¦ assQmbly means, means for providing data communication .~l 25 between each of the light assembly means and the processing ``!
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display having symbols representing the ground traffic, each of the 8ymbols having direction and velocity data displayed.
Each of the light circuits are located along the edges of ~;1; a taxiway or a runway on the airport. The light assembly ; i means comprises liqht means coupled to the lines of the power providing means for lighting the airport, sensing means which comprises infrared detectors, microproce~sor means coupled to the light means, the sensing means, and the data communication means for providing processing, communication and control for the light assembly means, the microprocessior controlling a plurality of lighting pat~erns ;, of the light means on the airportl and the data ~ 15 communication means are coupled ~o the microprocessor means ,~
and the lines of the power providing means. The light as~embly means further compri es a photocell means coupled to the microprocessor means for detecting the light intensity o~ the light means. ~he light assembly means further comprises a strobe ligh~ coupled to the microprocessor means. The processing means comprises redundant computers for fault tolerance operation. The ~`~ 3ymbol8 representing the ground traffic comprise icons 3 having a shape indicating the type of airplane or vehicle.
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the graphic display of the airport in accordance with the data receive from the light assembly means. The proce~sing means determines a fu~ure path of the ground traffic based on a ground clearance command, the future path being shown on the graphic display. The power providing means compri~e8 constant current power mean~ for providing a separate line to each of the plurality of light circuits, and network bridge means coupled to the constant current power mean~ for providing a communication chan~el to the proces~ing means :,.i for each line of the constant current power mean~.
The objects are fur~her accomplished by a method of providing an airport surveillance sy~tem co~prising the steps of providing a plurality of liyht circuits on the airport, each of the light circuit~ comprises a plurality of light assembly means, providing power to each of the plurality of light circuits, ~ensing ground ~raffic on the airport with mean~ in each of the light as~embly means, proce~sing data received from each of the light assembly means in computer mean~, pro~iding a graphic display of the airport comprising symbols represen~ing the ground traffic, each of the symbols having direction and velocity data di~playedt and providing data communication between the computer means and each of the light assembly means. The ~ 3tep of ~ensing the ground traffic on the airport comprises .;~ 25 the ~tep~ of lighting the airport with a light means coupled .

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to the power line~, providing infrared detectors for sensing ground traffic, per~orming processing, communication and control within the light as~embly mean~ with a microprocessor means coupled to the light mean~, the ~ensing means and data communication means, and coupling the data '' communication means between the microprQces~or mean~ and the I power lines. The step of proce~sing da~a comprises the steps of operating redundant computer~ for fault tolerance.
The 5tep of providing power comprises the steps of providing a separate line to each of the plurality of light circuits with a constant current power means, and providing a `l communication channel to the computer means for each line of the constant current power means u~ing a network bridge means. The step of providing a graphic display comprising 8ymbols representing the ground traffic comprises the step ~ of indicating a type of aircraft or vehicle with icons of .'l various shapes. The step of processing the data from each of the light assembly means comprises the step of ~i determining a location of the symbol~ on the graphic di~play of the airport in accordance with the data.

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a :., ~ - Brief Description of the Drawings :.:. Other and further features of the invention will become I apparent in connection with the accompanying drawings ;;j wherein:
S FIG. 1 is a block diagram of the invention of an airport vehicle detection system;
FIG. 2 is a block diagram of an edge light assembly showing a sensor electronics unit coupled to an edge ligh~
of an airfield lighting system;
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:1 10 . FIG. 3 is a pictorial diagram of the edge light a3sembly showing the edge light positioned above the ~ensor . electronic~ unit;
FIG. 4 i~ a diagram of an airfield runway or taxiway ~ having a plurality of edge light assemblies positioned along :~ 15 each side of the runway or taxiway for detecting various .~ size aircraft as sho~n;
~j~ FIG. 5 is a block diagram of the central computer system shown in FIG. l;
FIG. 6 show~ eleven network variables used in :~1 programming the microprocessor of an edge light assembly to interface with a sensor, a light and a strobe light;
FIG. 7 is a block diagram showing an interconnection of network variables for a plurality of edge light assemblies ~ located on both sides of a runway, each comprising a ~ensor `~ 25 electronics unit 10 positioned along a taxiway or runway;

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FIG. 8 shows a graphic display of a typical taxiway/runway on a portion of an airport as seen by an operator in a control tower, the display showing the location of vehicles as they are detected by the sensors mounted in the edge light assemblies located along ~axiways and runways; and I FIG. 9 is a block diagram of the data flow within the:1 i By8tem shown in FIG. 1 and FIG. 5.
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.:' ' . ~es~ription of the Preferred Embodiment , .i Referring to FIG. 1 a block diagram of the invention of ~;~ an airport vehicle detection i3ystem 10 iS shown comprising a ¦ plurality of light circuits 181n, each of said light circuits 18,n comprises a plurality of edge light assemblies ~; 201n connected via wiring 211n to a lighting vault 16 which i8 connected to a central computer ~y~tem 12 via a wide area ¦ network 14. Each of ~he edge light assemblies 201n comprises an infrared (IR) detector vehicle sensor 50 (FIG.
2).
The edge light assemblies 201n are generally located alongside the runways and taxiways of the airport with an . . .
~' average 100 foot spacing and are interconnected to the ,~ lighting vault 16 by single conductor ~erie~ edge light wiring 211n. Each of the edge light cir~uits 181nis powered via the wiring 211~ by a constant current supply .; ~
241n located in the lighting vault 16. ~.
Referring now to FIG. 1 and FIG. 2, communication between the edge light a~emblie~ 201n and the central computer system 12 i8 accompli~hed with LON Bridges 221n interconnecting the edge light wiring 211n with the Wide .~, Area Network 14. Information from a microprocessor 44 ~'~ located in each edga light assembly 201n i~ coupled to the edge light wiring 211n via a power line modem 54. The ~ON
bridge~ 221n tran~fers mes3age information from the edge ,~
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light circuits 181n via the wiring 211~ to the wide area network 14. The wide area network 14 provide~ a transmission path to the central computer ~ystem 12. These circuit components also provide the return path communicationfi link from the central computer ~ystem 12 to the microprocessor 44 in each edge light assembly 2O1 D-, .. .
~ Other apparatus and methods, known to o~e of ordinary ~kill ~,.j in the art, for data co~munication between the edge light as~emblies 201n and the central computer system 12 may be i 10 employed, such as radio techniques, but the present ; embodiment of providing data communication on the edge light wiring 211n provide~ a low co~t sy~t~m for present airports.
1 The LOM Bridge 22 may be embodied by devices manufactured by Echelon Corporation of Palo Alto, California. The wide area network 14 may be implemented by one of ordinary skill in the art using standard Ethernet or Fiber Distributed Data Interface (FDDI) component~. The constant current supply 24 may be embodied by devices manufactured by Crouse-Hind~ of Winslow, Connecticut.
Referring now to FIG. 2 and FIG. 3, FIG. 3 shows a ~'~! pictorial diagram of the edge light a~sembly 201n. The edge ;, light assem~ly 201n comprises a be~el including an ~ incandescent lamp 40 and an optional ~trobe light assembly `~ 48 (FIG. 2) which are mounted above an electronics ienclosure `~; 25 43 comprising the vehicle ~ensor 50. The electronics ~ .~
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`! enclosure 43 sits on the top of a tubular ~haft extending :I from a base support 56. The light as~embly bezel with lamp 40 and base support 56 may be embodied by devices ¦ manufactured by Crouse-Hind~ of Winslow, Connecticut.
A block diagram of the contents of the electronics ~¦ enclo~ure 43 is shown in FIG. 2 which comprises a coupling transformer 53 connected to the edge light wiring 211~. The coupling ~ransformer 53 provides pow~r to both the candescent lamp 40 via the lamp control triac 42 and the .~l 10 microprocessor power supply 52; in addition, the couplinq ` transformer 53 provides a data communication path ~etween `~ the power line modem 54 and the LON Bridges 22,n via the l' edge light wiring 211n. The microproces30r 44 provides the .~ computational power to run the internal software program that controls the edge light assemblies 201n. The microprocessor 44 i~ powered by the microprocessor power supply 52. Al~o connected to the microproce~sor 44 is the lamp control triac 42, a lzmp monitoring photo cell 46t the optional strobe light as~embly 48, the vehicle ensor 50, and the data communications modem 54, The microproces~or 44 i~ used to control the incandescent edge light 40 inten~ity and optional ~trobe light assembly 48. The use of the ~ ."
~ microprocessor 44 in each liqht assembly 201n allows i~
complet~ addre~sable control over every light on the field.
The microproces~or 44 may be embodied by a VLSI device .. ,j , .

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Still referring to FIG. 2, the sensor 50 in the present embodiment compris2s an infrared (IR) detector and in other embodiments may comprise other devices such as proximity detectors, CCD cameras, microwave motion detector~, -~ inductance loops, or laser beams. The program in the ~i microproce~sor 44 is responsible for the initial fil~ering of the sensor data received from the sensor 50 an~
re~pon~ible for the tran~mission of suoh data to the central computer system 12. The sensor 50 must perform the ollowing functions: detec~ a stationary ob~ect, detect a moving object, have a range at least half the width of the runway or taxiway, be low power and be immune to false - 15 alarms. This sys~em design does not rely on ~u~t one type of sen~or. since sensor fusion functions are performed within the cen~ral computer system 12, data input~ from all - .
different types of sensor~ are acceptable. Each sensor ~'' relay~ a different view of what i~ happening on the airfield and the central computer system 12 combines them. There are ~,' a wide range of ~ensors that may be used in this system.
As a new sen~or type becomes available, it can be integrated .
i~to this system with a minimum of difficulty. The initial ensor u~ed is an IR proximi~y detector based around a ~' 25 piezoelectric strip. ~hese are the kind of sensors you u~e ~`, 14 ., ., ~ . . . . .
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at home to turn on your flood lights when heat and/or movemen~ i~ detected. When the sensor output provides an analog ~ignal, an analog-to-digital con~arter readily known in the art may be used to interface with the microproces~or 44.
Another proximity detector tha~ can be used is based , around a microwave Gunn diode oscillator. These are ;~ cl~rrently in use in such applications as Intrusion Alarms, Door Openers, Distance Measurement, Collision Warning, Railroad Switchingl etc. These types of sen30rs have a ! "
drawback because they are not passive devices and care needs to be taken to select frequencies that would not interfere , with other airport equipment. Finally, in locations such as the hold position lines on taxiway~, ~olid state laser and lS detector combinations could be used between ad~acent taxiway hts. These sensor ~ystems create a beam tha~ when ~ broken would identify the location of the fron~ wheel of the `?~
airplane. This type of detector would be used in those locations where the absolute position of a vehicle was needed. The laser bea~ would be modulated by the microprocessor 44 to avoid the detector being fooled by any other ~tray radiation.
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Referring to FIG. 2 and ~IG. 4, a portion of an airport runway 64 or taxiway is shown having a plurality of edge ; 25 light assemblieis 20l8 positioned along each side of the , .

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: runway or taxiway for detecting various size ai~planes or , vehicles 60, 62. The dashed lines represent the coverage `. area of the ~ensors 50 located in each edge light as~embly .; 2018 po3itioned along each ~ide of the runway 64 or taxiway ~o insure detection of any airplane 60, 62 or other vehicle~
traveling on such runway 64 or taxiway. The edge light assemblies 201n comprising the sen~or 50 are logically connected together in such a way that an entire airport is . sencitized to the movement of vehicles. Node to node communication takes place to verify and identify the location of the vehicles. Once this is done a message is ent to the central computer system 12 reporting the j vehicles location. Edge light assemblies (without a sensor 3, electronics unit 43) and taxiway power wiring currently 1 15 exist along taxiways, runways and open areas of airports;
':3 therefoxe, the sensor electrQnics unit 43 is readily added to existing edge lights and existing taxiway power wiring -~
without the inconvenience and expense of closing down , runways and taxiways while installing new cabling.~;
l 20 Referring no~ to ~IG. 1, ~IG. 5, FIG. 8 and FIG. 9, the :~ central computer system 12 is generally located at a control tower or terminal area of an airport and is interconnected ., to the LON Bridges 221n located in the lighting vault 16 with a Wide Area Network 14. The central computer system 12 comprises two redundant computers, computer #1 26 and ~ 16 ., ,,, ~ ., . : .

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: :l ~, computer #2 28 for fault tolerance, the display 30, speech synthesis unit~ 29 & 31, aler~ lights 34, keyboard 27 and a speech recognition unit 33, all of these elements being interconnected by the wide area network 14 for the transfer of information. The two computers 26 and 28 communicate ::j ~ with the microproces ors 44 located in the edge light ,~,.,j ~.3 assemblies 201n. Data received from the edge light assembly s 201~ microprocessors 44 are used as an input to a sensorfusion software module 101 (FIG. 9) run on the redundant computers 26 and 28. The output of the ~ensor fusion :! software module 101 operating in the computer~ 26, 28 is ~ used to drive the CRT display 30 which displays the location ~!~ of each vehicle on the airport taxiway and runways as shown .~``1 ~ in FIG. 8. The central computer system 12 may be embodied .~ ;, by devices manufactured by IBM Corporation of White Plains, New York. ~he Wide Area Network 14 may be embodied by ~ devices manufactured by 3Com Corporation of Santa Clara, :~ California. The speech synthesis units 29, 31 and the speech recognition unit 33 may be embodied by devices ~; 20 manufactured by BBN of Cambridge, Massachusetts.
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~ The speech synthesis unit 29 is coupled to a speaker ;~ 32. Limited information is sent to the speech synthesis unit 29 via the wide area networX 14 to provide the ,,i;
capability to give an air traffic controller a verbal alert.
The speech synthesis unit 31 is coupled to a radio 37 having - 2~1~7-i~
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an antenna 39 to provide the capability to give the pilots a verbal alert. The voice commands from the air traffic controller to the pilots are captured by microphone 35 and sent to the pilots via radio 36 and antenna 38. In the present embodiment a tap is made and the speech information i5 sent to both the radio 36 and the speech recognition unit 33 which is programmed ~o recognize the limited air traffic control vocabulary uged by a controller. This includes airline names, aircraft type, the numbers 0-9, the name of the taxiways and runways and variou~ short phrase~ such as "hold short", "expedite" and "give way to." The output of " the speech recognition unit 33 is fed to the computer~ 26, ~n o .
Referring again ~o FIG. 2, the power line modem 54 , 15 provides a data communication path over the edge light , wiring 211 D for the microprocessor 44. This ~wo way path is ;~ used for the pas~ing of command and control information -~, between the various edge light assemblies 2O1-D and the central computer system 12. A power line transcqiver module in the power line modem 54 i8 used to provide a data channel. These modules use a carrier current approach to create the data channel. Power line modems that operate at carrier frequencies in the 100 to 450 Rhz band are available from many manufacturers. These modems provide digital communication paths at data rates of up to 10,000 bits per , ~

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!~ second utilizing direct 6equence spread spectrum modulation.
They conform to FCC power line carrier reguirements for conducted emissions, and can work wi~h up to 55 dB of power . ., 3 line attenuation. The power line modem 54 may be embodied by a device manufactured by Echelon Corporation of Palo Alto, Cali~ornia 94304, called the PLT-10 Power Line Transceiver Nodule.
The data channel provides a transport layer or lowe~t layer of the open ~ystem intorconnection (OSI) protocol used in the data network. The Neuron~ chip which implements the .:j ~!~ microprocessor 44 contains all of the firmware required to implement a 7 layer OSI protocol. When interconnected via an appropriate madium the Neuron~ chips automatically communicate with one another using a robust Collision Sense ~ultiple Access (CSMA) protocol with forward error ., ~
corrections, error checking and automatic retransmission of missed mes~ages (ARQ).
The command and control information i5 placed in data packe~s and sent over the network in accordance with the 7 Layer OSI protocol. All messages generated by the microproce~sor 44 and destined for the central computer ;~ sy~tem 12 are received by the network bridge 22 via the power line~ 211n and routed to the central computer system 12 over the wide area network 14.

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The ~euro~ chip of the microprocessor 44 comprises three processors (not shown) and the firmware required to support a full 6 layer open ~ystems interconnection (OSI) protocol. The user is allocated one of the processors for the application code. The other two processors give the application program access to all of the other Neuron~ chips ~ in the network. ~his acces~ creates a Local Operating ;~, Network or LON. A LON can be thought of as a high level local area network LAN. The use of the Neuron chip for the implementation of khis invention, reduces the amount of custom hardware and software ~hat otherwise would have to be developed.
~` Data from the sensor electronic unit 43 of the edge ;~ light as~emblies 201n i8 coupled to the central computer system 12 via the existing airport taxiway lighting power wiring 21. usin~ the existing edge light power line to transfer the sensor data inko a LON network has many .`1 .
advantages. As previously pointed out, the reuse of the existing edge light3 eliminates the inconvenience and expense of closing down runways and taxiways while running new cable and provides for a low cost syitem.
. ' The Neuron~ chip allows the edge light assemblies 20 to automatically communicate with each other at the applications level. This is accomplished through network variables which allow individual Neuron~ chips to pass data :. :
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between themselves. Each Neuron~ ~C~ program comprises both local and network variables. The local variables are usQd by the Neuron~ program as a scratch pad memory. The network 'i variables are used by the Neuron~ program in one of two "1 ways, either as a network output variables or a network input variable Both kinds of variables can be initialized, evaluated and modified locally. The difference ~ comes into play in tha~ once a network output variable is ;;~ modified, network ma~sages are automatically sent to each `~ 10 network input variable that is linked to that output variable. This variable linking is done at installation time. As soon as a new value of a network input variable is received by a Neuron~ chip, the code i5 vectored off to take appropriate action based upon the value of the network input variable. The advantage to the program is that this message passing scheme is entirely transparent since the message passing code i~ part of the embedded Neuron~ operating .~
system.
Referring now to FIG. 6, eleven network vari~bles have ~ 20 been identified for a sensor program in each microprocessor ,.`~1 44 of the edge light assembliec 201~. The sensor 50 ~unction has two output variables: prelim detect 70 and ~i confirmed detect 72. The idea here is to have one output trigger whenever the sensor 50 detects movement. The other output doe~ not trigger unles~ the local sensor and the . . . :: . . ~ , :,~,:' : ,': . ~ ' :` 2 L I !~ 7 j :
sensor on the edge light across the runway both 8pot movement. Only when the detection i8 confirmed will the signal be fed back to the central computer system 12. Thif technigue of confirmation helps to reduce false alarms in order to implement thi3 techniff~ue the ad~acent sensor 50 has an input variable called ad~_preflim detect 78 that is used to receive the other sensor3 prelim_detect ou~pu~ 70. Other input variables are upstream detect 74 and downstreff~m detect 76 which are used when chaining ad~jacent sen30rs together.
Also needed i8 a detector sensi~ivity 80 input that is used by the central computer sy~tem 12 to control the detection ability of the sensor 50.
~ The incandescent light 40 raquires two network ;' variables, one if nput and the other an output variable. The ~, 15 input variable light_level 84 would be used to con~rol the light~ 8 brightness. The range would be OFF or 0~ all the way to FULL ON or 100%. This range from 0% to lOO~ would be made in O.5% steps. Since the edge light assembly 201~f also . .
3 containfs the photocell 46, an output variable light failure `,f 20 84 is created to siff~nal that the lamp did not obtain the ,.1 desired brightness.
The strobe light 48 requires three input variables.
The strobe-mode 86 varlable i3 used to select either the "I OFF, SEQUEMTIAL, or ALTERNATE flash modes. Since thef two ~ 25 flash modes ref~uire a distinct pattern to be created, two ` :`,t ~ - 22 `"' ;, : 'J

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~ ,1 ,~ input variables active_delay 88 and fla~h delay 90 are u~ed to time align the strobe flashes. By setting the~e individual delay factors and then addressing the Neuron~
chips as a group, allows the creation of a field strobe pattern with ~ust one command.
l Referring now to ~IG. 7, a block diagram of an ;;~ interconnection of network variables for a plurality of edge ... .
;~ light assemblies 20,~ located on both 3ides of a runway is `~ shown, each of the edge light a~semblies 201n comprising a microprocessor 44. Each Neuron program in the microprocessor 44 i5 designad with certain network input and output variables. The user writes the code for the Neuron~
chips in the microprocessor 44 assuming that the inputs are ~upplied and that the outputs are u~ed. To create an actual network the user has to "wire up" the network by , interconnecting the individual node~ with a software linker. The resulting distributed process is best shown in schematic form, and a portion of the network interconnect matrix i~ shown in Figure 7. The preliim detect 70 output of ; 20 a sensor node 441 i8 connected to the ad~ primary detect 92 input of the sensor node 444 across the taxiway. This i~
used as a means to verify actual detections and eliminate fal~e reports. The communications link between these two nodes 441 and 444 i8 part of the distributed processing.
The two nodes c~mmunicate hmong themselves without involving 23 ` ` `~

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the central computer ,system 12. If in the automatic mode or if in,structed by the controller, the syst~m will al80 alert the pi10ts via audio and vi~ual indications.
Referring again to FIG. 1 and FIG. 4, the central computer syætem 12 track,s the movement of vehicles as they pass from the æensor 50 to sensor 50 in each edge light asse3~bly 201 n. ~Bing a varia~ion of a radar automatic track ;, algorithm, the system can track position, velocity and heading of all aircraft or vehicles based upon the sensor 50 readings. New vehicles are entered into the sys~em either upon leaving a boarding gate or landing. Unknown vehicles 1 are al50 tracked automatically. Since taxiway and runway ;1 lights are normally across from each other on the pavement ; (as shown in FIG. 4 and FIG. 7), the microproce~or 44 in each edge lightq assembly 2 l-n iS programmed to combine their sensor 50 inputs and agree before reporting a contact.
~ I
A further refinement is to have the microprocessor 44 check with the edge light assemblies 201n on either side of them .
to see if their sensors 50 had de~ected ~he vehicle. This allows a vehicle to be handed off from q3ensor electronic unit 43 to sensor electronic unit 43 of each edge light asæe3mbly 20~ as it travel~ down the taxiway. This also `~, assures tha~ vehicle position reports remain consistent.
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;~ Vehicle velocity may also be calculated by using the r~

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;i distance between sensors, the sensor pattern and the time between detections.
Refexring to FIG. 5 and FIG. 8, the display 30 is a il color monitor which provides a graphical display of the :' airport, a portion oif which is shown in FIG. 8. This i~
accomplished by storing a map of the airport in the ~, redundant computers 26 and 28 in a digital format. The display 30 shows the location o~ airplanes or vehicles as they are detected by the sensors 50 mounted in the edge ~, 10 light assemblies 201n along each taxiway and runway or other i~;
airport surface areas. All aircraft or vehicles on the airport surface are displayed a~ icons, with the shape of `~ the icon~ being determined by the vehicle type. Vehicle posit~on i~ shown by the location of ~he icon on the screen.
Vehicle direction i8 shown by either the orientation of the icon or by an arrow emanating from the icon. Vehicle status i8 conveyed by the color of the icon. The future path of .. ~ .
the vehicle as provided by the ground clearance command entered via the controller~ microphone 35 is ~hown as a colored lina on the display 30. The status of all field `"l .
lightci including each edge light 201n in each edge light circuit 18~_D i8 ~hown via color on the display 30.
Use of ob~ect orientated software provides the basis :1 for building a model of an airport. The automatic ~ 25 inheritance feature allows a data structure to be defined 'a 25 ~ .,, ~.

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once for each object and then replicated automatically for each instance of that ob~ect. Automatic flow down a~sures that elements of the data base are not corrupted due to typing errors. It also assures tha~ the code i3 regular and structured. Rule based ob~ect orientad programming make~ it difficult to create unintelligible l~paghetti code." Object oriented progra~ming allows the runways, taxiways, aircraft ~: and sensors, to be decoded directly as ob~ect~. ~ach of these ob~ects contains attributes. Some of the~e a~tributes are fixed like runway 22R or flight UA347, and some are variable like vehicle status and position.
i In conventional programming we describe the attributes `~ of an ob~ect in data structures and then describe thebehaviors of the object as procedures that operate on those data structures. Ob~ect oriented programming shifts the emphasis and focusas first on the data 8 ruc~ure and only ; secondarily on the procedures. More importantly, ob~ect ~ oriented programming allows us to analyze and design i programs in a na~ural mannar. We can ~hink in term~ o runways and aircraft instead of focusing on either the behavior or the data structures of the runways and aircraft.
,.
Table 1 shows a lis~ of ob~ects with corresponding ~i, attributes. Each physical ob~ect that is important to the runway incursion problem is modeled. The basic airplane or vehicle tracking algorithm is shown in ~able 2 in a Program :.
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Design Language (PDh). The algorithm which handles 3ensor :i fusion, incursion avoidance and safety alert~ is sho~n in a single program even though it is implemented as distributed 3j system using both the csntral computer sy~tem 12 and the sensor microprocassors 44.
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0 D RCT ATTRI~U~ DRsc3LnprIo~
Sensor ~ocation X & Y coord1nrtes o~ oensor Cirauit AC wlrlng circult na~e fi numbar ~¦ 1 0 Unlquo nddress Net addres~ for this aensor and it~ mata ~mp_intansity 0~ to lO0~ ln 0.5~ step~
. Strobe atatus ~link rate/off ,: Strobs-delay From start slgnal .j Sensor_st~tus Detect/no detect Sensor type IR, laser, pro~clmlty, eto.
unway N~o 22~, 27, 331, etc.
~ocntlon X ~ Y coordln~tes of start of center llne Length In feet ~ Wldth In feet .~ 20 Dlrection In degrees fr north ;~ St~tus Not actlve, actlve takaoff, actlve landing, alilrm . Sensors (~v) Llst of llghts/sensors along thls runway :. Intersections (hV) List o~ lntersections .~ Vehicles ~lst of vehlcles on the run~ay ~, 25 T~ciway N~me N ~ of taxiway .I Location X & Y coordinatea of start of center line :~
`1 Length In feet n~ Wldth In feat Directlon In degrees from north 3n Stntus Not actlve, actlve, alarm ~, Sensors (HV) List of intersectlons Hold ~ocatlons Llst of holdlng locntlons Vehlcles (~V) Llst of vehlcles on the runway ~,.
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Inter~ection Nama Intersfiction No~e I ~oa~tion Intar~ectlon of two centar lines ~, St~tus V~cant/Occupled Sensors (~V) Llst of ~en~ors creating lntersection 'oorder Aircraft Airline Bnitad ~odel 727-200 Tail-nw~'oer N3274Z
mp~y waight 9.5 tona .~ Frelght weight 2.3 tona "~ 1 0 Fuel weight 3.2 ton~
~'~, Top speed 598 ~ph Vl ~paed 100 mph ~'1 V2 speed 140 mph j Accelarotlen 0.23 g~a Deaaler~tion 0.34 9'8 ~V - Multi-~ri~bla or ~rr~y T~le 2 while (forever) ¦ if (edge lLght showu a detectLon) .~. . ~ .
~ ad~acent light al~o ~hown a detection ~enaor ~u~ion) 'i ¦ ¦ ¦ /~ CON~IRN~D DETECTIO~ */ :-¦ ¦ ¦ if (previoua blook showed a detection) ~-., ¦ ¦ ¦ ¦ /* ACCEPT HANDOFF */
¦ ¦ ¦ ¦ Update aircraft po~ition and ~p~ed 1 1 1 else ¦ ¦ ¦ ¦ /* ~QaY 3E aUN }iNI~U~L OR SERVI OE ~RUCK ~/
¦ ¦ ¦ ¦ ~lert operator to po~aLble incursLon ¦ ¦ /* ~L~Y ~E iiN AIRC$ W FT ENTERING THE SYSTE~
¦ ¦ ¦ ¦ Start a new track 1 1 else ¦ ¦ ¦ Request atatus from ad~acent light , ,~

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, `1 ¦ ¦ ¦ lf (Adjacent light i~ OK) ¦ ¦ /* NON CONFIRNED D~TECTION */
el~
Flag ad~ac~nt light for r~pair ~ 5 j ¦ ¦ endif `~ ¦ ¦ endi~
¦ ¦ endif if (Ed~e light lo~e~ a detec~ion AND ~tatu~ i~ OR) ¦ if ~Next block ehowed a detection) j j j /* PROPER ~ANDOFF */
el~
¦ if (vehicle ~peed ~ 3 takeoff) ~, ¦ ¦ ¦ ¦ Handoff to departure control 9 I I I el~e ¦ ¦ ¦ ¦ /* MISSING HaMDOFF ~/
y~, ~, ¦ ¦ ¦ ¦ Alert operator to possibl~ incur~ion ~ ¦ ¦ ¦ endif :1 ¦ ¦ endif ~'~ ¦ endif ¦ /* CHECR FOR POSSIBLE COLLISIO~S */
¦ for ~all tracked air~raft) : :
`,~ j I Plot futura position j j if ~po~ition con~lict) .~ I I I Alert op~rator to po~ible incur~ion .'~ 25 ¦ ¦ endif ndif ~`~ ¦ Update display endwhil~
~ Referring again to FIG. 1 and FIG. 2, the control of .~i . taxiway lighting intensity is u~ually done by placing all . .~

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the lights on the ~ame series circuit and then regulating the current in that circuit. In the present ambodiment the intensity of the lamp 40 is controlled by sending a mes~age with the light intensity value to the microprocessor 44 ~" S located within the light assembly 201n. The message allows -)~ for intensity settings in the range of 0 to 100% in 0.5~
steps. The use of photocell 46 ~o check ~he light output allows a return message to be sent if the bulb does not respond. ~his in turn generates a maintenance report on the light. The strobe light 48 provides an additional optional capability under program control of the microprocessor 44.
Each of the microprocessors 44 in the edge light assemblies .~ 20 i8 individually addressable. This means every lamp on the field i8 controlled individually by the central computer system 12. ~-The sy~tem 10 can be programmed to provide an Active Runway Indicator by using the ~trobe lights 48 in tho~e edge light assemblies 201n located on the runway 64 to continue the approach light ~rabbit~ ~trobe pattern all the way down the runway. This lighting pattern could be turned-on as a plane is cleared for landing and then turned~off a~ter the aircraft has touched down. A pilot approaching the runway along an intersecting taxiway would be alerted in a clear ; and unambiguous way that the runway was active and should not be crosqed.

~ 2 1 14753 '~`1 If an incursion was detected the main computers 26, 28 could switch the runway strobe ligh~s 48 from the ~rabbit~
~ pattern to a pattsrn that alternatively fla~hes either side ..~
of the runway in a wig-wag fashion. A ~witch to this pattern would be interpreted by the pilot of an arriving aircraft as a wave off and a signal to go around. The abrupt switch in the pattern of the strobes would be instantaneously picked up by the air crew in time for them to initiate an aborted landing procedure.
~'~ 10 During Category III weather conditions both runway and taxiway visibility are very low. Currently radio based ,, ~
landing systems are used to get the aircraft from final 1 approach to the runway. Once on the runway it i8 not always -1 obviou~ which taxiways are to be u~ed to reach the airport terminal. In system l0 the main computers 26,28 can control the taxiway liamp~ 40 as the mea~s for guiding aircraft on ':~
the ground during caT III conditions. Since ~he inten~ity ~I
of the taxiway lamps 40 can be controlled remotely, the ~`t lamps ~ust in front of an aircraft could be intensified or flashed a~ a means of guiding it to the terminal.
~\` Altexnatively, a short sequence of the ~rabbit" pattern "I; may be programmed into the taxiway ~trobes ~ust in front of the aircraft. At intersections, either the unwanted paths ~,~ may have their lamp~ turned off or the entrance to the proper section of taxiway may flash directing the pilot to .Z
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head in that direction. Of course in a smart system only those lights directly in front of a plane would be controlled, all other lamp5 on the field would remain in their normal mode.
Referring now to FIG. 9, a block diagram is ~hown of the data flow within the system 10 (as shown in FIG. 1 and FIG. 5). The software modules are shown that are u~ed to '~ proces~ the data within the computers 26, 28 of the central computer system 12. The tracking of aircraft and other l 10 ~ vehicles on the airport operates under the control of a i~ sensor fusion ~oftware module 101 which resides in the computers 26, 28. The sensor fusion software module 101 receives data from the plurality of ~ensors 50, a sensor 50 ,..
being located in each edge light assembly 201~ which reports the heat level detected, and this ~oftware module 101 :'~
combine~ this information through the u8e of rule based -.
artificial intelllgence to create a complete picture of all ground traffic at the airport on a display 30 of the central computer system 12.
The tracking algorithm ~tarts a ~rack upon the first report of a sen~or 50 detecting a heat level that is above `, the ambient background level of radiation. This detection is then verified by checking the heat level reported by the ~ sensor directly acros~ the pavement from the first reporting `~ 25 sensor. This secondary reading i8 used to confirm the ~- 32 ` ;~

- ., ~ i -~ :l --- ` 2 ~ 3 ~ 7 3~3 ~3 vehicle detected and to eliminate false alarm~. After avehicle has been confirmed the sensors ad~acent to the first reporting sensor are queried for changes in their detected heat level. As soon a~ one of the adjacent sensors detects a rise in heat level a direction vector for the vehicle can be established. This process conti~ues as the vehicle is handed off from sensor to sensor in a bucket brigade fashion as shown in FI~. 7. Vehicle speed can be roughly determined by calculating the time bet~een vehicle detection by ; 10 ad~acent sensors. This information is combined with l information from a siystem data base on the location of each 'q sensor to calculate the velocity of the target. Due to hot exhau~t or ~et blast, the sensor~ behind the vehicle may not return to a background level immediately. Because of these ,.,~
,~3 15 condition, the algorithm only u~es the first four sensor~`1 (two on either side of the ~axiway) to calculate the vehicles position. The vehicle i5 always as~umed to be on the centerline of the pavement and between the first four reporting sen30rs.
: ~y ;l, 20 Vehicle identification can be added to the track either j manually or automatically by an automated source that can , identify a vehicle by it8 po~ition. An example would be S
prior knowledge of the next aircraft to land on a particular runway. Tracks are ended when a vehicle leaves the detection system. This can occur in one of two ways. ~he ' .. ...
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first way is that the vehicle leaves the area covered by the sensors 50. Thi~ is determined by a vehicle track moving in the direction of a gateway sen~or and then a lacX of detection after the gateway sensor has lo~t contact. A
~econd way to leave the detection system is for a track to , be 108t in the middle of a sensor array. This can occur when an aircraft departs or a vehicle runs onto the grass.
~akeoff scenarios can be determined by calculating the speed of the vehicle ju6t before detection was lost. If the vehicle xpeed was increa~ing and above rotation speed then the aircraft is assumed to have taken off. If not then the vehicle i~ assumed to have gone on to the gras~ and an alarm ~ is sounded.
;~ Referring to FIG. 5 and FIG. 9, the ground clearance routing function is performed by the speech recognition uni~
33 along with the ground clearance compliance verifier l software module 103 running on the computer~ 26, 28. ~hi~
., ~oftware module 103 comprises a vehicle identification ,.~
routine, clearance path routing, clearance checking routine and a path checking routine.
;., ~he vehicle identification routine i5 used to receive the airline name and flight number (i.e. ~Delta 374") from ~; the speech recognition unit 33 and it highlights the icon of 1 that aircraft on the graphic display of the airport on display 30.

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The clearance pa~h routine takes the remainder of the controller~s phra~e (i.e. "outer taxiway to echo, hold ~hort of runway 15 Left") and provides a graphical display of the clearance on the display 30 showing the airport.
The clearance checking routine checks the clearance path for po~sible conflict with other clearance~ and vehicles. If a conflict i~ found the portion of the path ~ that would cause an incursion i8 hîghlighted in a blinking `'!;'~l red and an audible indication is given to the controller via speaker 32.
The path checking routine checks the actual path of the vehicle as detected by ~he ~ensors 50 after the clearance path has been entered into the computers 26, 28 and it monitors the actual path for any deviation. If this routine detects that a vehicle has strayed from the as3igned course r the vehicle icon on the graphic display of the airport l, flashes and an audible indicator is given to the controller :~ via speaker 32 and optionally the vehicle operator via radio ::
37.
i 20 The airport system 10 operates in a vehicle detection mode under th~ control of safety logic routines which re~ide in the colli~ion detection sof~ware module 104 running on :~
computers 26, 28. The safety logic routines receive data -1 from the sen~or fusion software module 101 via the tracker .~ 25 software module 102 location program and interpret thiC
,~
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2 ~ ~ ~ 7 i 5 ,; ', `~ information through the use of rule based artificial intelligence to predict possible collisions or ru~way incursions. Thii information is then used by the centxal ' computer sy~tem 12 to alert tower controllers, aircraft pilots and truck operators to the possibility of a runway incursion. The tower controllers are alerted by the display 30 along with a computer syntheiized voice message via `~ speaker 32. Ground traffic i~ alerted by a combination of traffic lights, flashing lights, stop bars and other alert lights 34, lamps 40 and 48, and computer generated voice commands broadcast via radio 36.
Knowledge based problems are also called fuzzy problems and their solutions depend upon bo~h program logic and an , ! interface engine that can dynamically create a decision ~ 15 tree, selecting which heuris~icsi are most appropriate for q the specific case being considered. Rule based isystems ;~1 broaden the scope of possible applications. They allow de~igners to incorporate ~udgement and experience, and to take a con~istent solution approach aGxoss an entire problem set.
The proqramming of the rule based incuriion detections software is very straight forward. The rules are written in English allowing the expert~, in this case the tower per~onnel and the pilots, to review the system at an j 3 25 understandable level. Another feature of the rule based " ., ~3 36 ,,,;,~

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~'1 system is that the rules stand alone. They can ~e added, I deleted or modified wi~hout affecting the rest of the code.
t This is almost impo~sible to do with code that is created 1 from scr tch. An example of a rule we might use i~
i 5 If 5Runway_Status = Activ~) hen ~Stop Bar Lights - RED).
This is a very simple and straight forward rule. It stands alone requiring no extra knowledge except how Runway_Status i8 created. So let~s make some rules affecting ~i 10 Runway Status.
If ~Departure = APPROVED) or ~Landing = IM~INENT)~
then ~Runway_Status = ACTIVE).
For incur~ion detection, another rule is:
If (Runway Statu~ = ACTIVE) and (Intersection = OCCUPI~D), th~n (Runway Incur~ion - TRUE).
: 1 Next, datect ~hat an intersection of a runway and taxiway are occupiQd by the rules~
. If ~Internection S~nnors = D~TECT), . ~::
', then ~Inter~ection a OCCUPIED).
-~ 20 To predict that an aircraft will run a Hold Position stop, the following rule is created:
If ~Aircraft Stopping Di~tance ~ Di~tance to Hold Po~ition), then ~Intersection = OCCUPIED).
In order to show that rules can be added without affecting the reset of ~he program, assume that after a demonstration of the syste~ 10 to tower controllers, they ~ 37 `i ~:

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, ~( decided that they wanted a ~Panic Button~ in the tower to .~.J override the rule based software in ca~e they spot a ~afety violation on the ground. Besides in~talling the button, the only other chanqe would be to add this extra rule.
~! If (Panic button ~ PRESS~D), then (Runway Incu~Lon s TRUE).
It is readily ~een that the central rule ba~ed computer program is very straight forward to create, understand and modify. A~ types of incursions are defined, ~he ~ystem 10 ;~( 10 can be upgraded by adding more rulex.
.. 1 .
~ Referring again to FIG. 9, the block dia~ram ~hows the :
/i data flow between the functional elements within the sy~tem ~,, ~ 10 ~FIG. 1). Vehicles are detected by the sensor 50 in each 'J of the edge light assemblies 201n. ~his information is passed over the local operatinq network (LON) via edge light wiring 21~n to the LON bridges 221n. ~he individual message packet3 are then passed to the redundant computers 26 and 28 over the wide area network (WAN) 14 to tha WA~ interface 108. After arriving at the redundant computers 26 and 28, the message packet is checked and verified by a message parser ~oftware module 100. The content~ of the message are l then sent to the sen~or fusion software module 101. The '~ sensor fusion software module 101 is used to keep track of the status of all the sensors 50 on the airport; it filters and verifies the data from the airport and stores a ~"~

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,, representative pic~ure of the sensor array in a memory.
This înformation is used directly by the display 30 to show which sensors 50 are responding and used by the tracker ;l software module 102. The tracker software module 102 uses ; 5 the sensor status information to determine which sensor 50 reports correspond to actual vehicles. In addition, as the ;;l sensor reports and statu~ change, the tracker software module 102 identifies movement of the vehicles and produces a target location and direction output. This information is ~^ 10 used by the di~play 30 in order to display the appropriate vehicle icon on the ~creen.
The location and direction of the vehicle is also used by the collision detection software module 104. This module checks all of the vehicles on the ground and plots their expected course~ If any two targets are on intersecting , ~.
paths, this software module generates operator alerts by using the display 30, the alert lights 34, the speech synthesi~ unit 29 coupled to the a~sociated speaker 32, and the speech synthesis unit 31 coupled to r dio 37 which i5 ~ 20 coupled to antenna 39.
;~' Still referring to FIG. 9, another user of target ~, location and position data i~ the ground clearance compliance verifier software module 103. This software , module 103 receives the ground clearance commands from the `` 25 controller~ 8 microphone 35 via the speech recognition unit '~' ''' ' ' ' ''' . ~ ' '' " ' ' '' ' , ', 33. Qnce the cleared route has been determined, it i~
stored in the ground clearance compliance verifier software - module 103 and used for comparison to the actual route taken by the vehicle. If the information received from the tracker ~oftware module 102 ~hows that the vehicle ha~
deviated from its as~igned course, this software module 103 generates operator alerts by using the display 30, the alert lights 34, the speech synthesis unit 29 coupled to speaker ~, 32, and the ~peech synthesis unit 31 coupled to radio 37 which is coupled to antenna 39.
, . .
! The keyboard 27 is connected to a keyboard parser software module 109. When a command has been verified by the keyboard parser software module 109, it is u~ed to change display 30 options and to reconfigure the sensors and ~.
network parameters. A network configuration data base 106 is updated with the~e reconfiguration commands. This ~
information is then turned into LON message packets by the l, command message generator 107 a~d ~ent to the edge light assemblies 201n via the WAN interface 108 and the LON
:~ ~o bridgeS 221-n-"~1 This concludes the description of the preferred X
embodiment. However, many modifications and alterations will be obvious to one of ordinary skill in the art without departing ~rom the spirit and ~cope of the inventive .:~
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2 ~ 7 5 5 concept. Therefore, i~ is intended that the scope of this 1 invention be limited only by the appended claims.

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Claims (26)

1. An airport surveillance system comprising:
a plurality of light circuits on an airport, each of said light circuits comprises a plurality of light assembly means;
means for providing power to each of said plurality of light circuits and to each of said light assembly means;
means in each of said light assembly means for sensing ground traffic on said airport;
means for processing data received from each of said light assembly means;
means for providing data communication between each of said light assembly means and said processing means; and said processing means comprises means for providing a graphic display of said airport comprising symbols representing said ground traffic, each of said symbols having direction and velocity data displayed.

2. The airport surveillance system as recited in Claim 1 wherein:
each of said light circuits being located along the edges of a taxiway or a runway on said airport.

3. The airport surveillance system as recited in Claim 1 wherein said light assembly means comprises:

light means coupled to said lines of said power providing means for lighting said airport;
said sensing means;
microprocessor means coupled to said light means, said sensing means, and said data communication means for providing processing, communication and control for said light assembly means, said microprocessor controlling a plurality of lighting patterns of said light means on said airport; and said data communication means being coupled to said microprocessor means and said lines of said power providing means.

4. The airport surveillance system as recited in Claim 3 wherein:
said sensing means comprises an infrared detector.

5. The airport surveillance system as recited in Claim 3 wherein:
said light assembly means further comprises a photocell means coupled to said microprocessor means for detecting the light intensity of said light means.

6. The airport surveillance system as recited in Claim 3 wherein:

said light assembly means further comprises a strobe light coupled to said microprocessor means.

7. The airport surveillance system as recited in Claim 1 wherein:
said processing means comprises redundant computers for fault tolerance operation.

8. The airport surveillance system as recited in Claim 1 wherein:
said symbols representing said ground traffic comprise icons having a shape indicating type of airplane or vehicle.

9. The airport surveillance system as recited in Claim 1 wherein:
said processing means determines a location of said symbols on said graphic display of said airport in accordance with said data receive from said light assembly means.

10. The airport surveillance system as recited in Claim 1 wherein: .
said processing means determines a future path of said ground traffic based on a ground clearance command, said future path being shown on said graphic display.

11. The airport surveillance system as recited in Claim 1 wherein said power providing means comprises:
constant current power means for providing a separate line to each of said plurality of light circuits; and network bridge means coupled to said constant current power means for providing a communication channel to said processing means for each line of said constant current power means.

12. An airport surveillance system comprising:
a plurality of light circuits on an airport, each of said light circuits comprises a plurality of light assembly means;
means for providing power to each of said plurality of light circuits and to each of said light assembly means;
means in each of said light assembly means for sensing ground traffic on said airport;
means in each of said light assembly means coupled to said sensing means for providing communication and control for said light assembly means;
means for processing data received from each of said light assembly means;
means for providing data communication between each of said light assembly means and said processing means; and said processing means comprises means for providing a graphic display of said airport comprising symbols representing said ground traffic in accordance with said data received from each of said light assembly means, each of said symbols having direction and velocity data displayed.

13. The airport surveillance system a recited in Claim 12 wherein:
said sensing means comprises an infrared detector.

14. The airport surveillance system as recited in Claim 12 wherein:
each of said light circuits being located along the edges of a taxiway or a runway on said airport.

15. The airport surveillance system as recited in Claim 12 wherein:
said light assembly means further comprises a photocell means coupled to said communication and control providing means for detecting a light intensity of said light assembly means.

16. The airport surveillance system as recited in Claim 12 wherein:
said light assembly means further comprises a strobe light coupled to said communication and control providing means.

17. The airport surveillance system as recited in Claim 12 wherein:
said processing means comprises redundant computers for fault tolerance operation.

18. The airport surveillance system as recited in Claim 12 wherein:
said symbols representing said ground traffic comprise icons having a shape indicating type of airplane or vehicle.

19. The airport surveillance system as recited in Claim 12 wherein:
said processing means determines a future path of said ground traffic based on a ground clearance command, said future path being shown on said graphic display.

20. The airport surveillance system as recited in Claim 12 wherein said power providing means comprises:
constant current power means for providing a separate line to each of said plurality of light circuits; and network bridge means coupled to said constant current power means for providing a communication channel to said processing means for each line of said constant current power means.

21. A method of providing an airport surveillance system comprising the steps of:
providing a plurality of light circuits on said airport, each of said light circuits comprises a plurality of light assembly means;
providing power to each of said plurality of light circuits;
sensing ground traffic on said airport with means in each of said light assembly means;
processing data received from each of said light assembly means in computer means;
providing a graphic display of said airport comprising symbols representing said ground traffic, each of said symbols having direction and velocity data displayed; and providing data communication between said computer means and each of said light assembly means.

22. The method as recited in Claim 21 wherein said step of sensing said ground traffic on said airport comprises the steps of:
lighting said airport with a light means coupled to said power lines;
providing infrared detectors for sensing ground traffic;
performing processing, communication and control within said light assembly means with a microprocessor means coupled to said light means, said infrared detectors and data communication means; and coupling said data communication means between said microprocessor means and said power lines.

23. The method recited in Claim 21 wherein said step of processing data comprises the step of operating redundant computers for fault tolerance.

24. The method as recited in Claim 21 wherein said step of providing power comprises the steps of:
providing a separate line to each of said plurality of light circuits with a constant current power means; and providing a communication channel to said computer means for each line of said constant current power means using a network bridge means.

25. The method as recited in Claim 21 wherein said step of providing a graphic display comprising symbols representing said ground traffic comprises the step of indicating a type of aircraft or vehicle with icons of various shapes.

26. The method as recited in Claim 21 wherein said step of processing said data from each of said light assembly means comprises the step of determining a location of said symbols on said graphic display of said airport in accordance with said data.