United States Patent
`Farmakis et al.
`
`[19]
`
`[54] SATELLITE BASED AIRCRAFT TRAFFIC
`CONTROL SYSTEM
`
`[75]
`
`Inventors: Tom S. Farmakis, Sharpsburg; Russell
`D. Routsong, Peachtree City, both of
`Ga.
`
`[73] Assignee: Worldwide Notillcallons Systems,
`Inc., Atlanta, Ga.
`
`[21] Appl. No.: 633,192
`Apr. 16, 1996
`[22] Filed:
`
`Related U.S. Application Data
`
`[63] Con~uation of Set. No. 275,547, Jul. 15, 1994, abandoned,
`which is a continuation-in-part of Set. No. 62,406, May 14,
`1993, Pat. No. 5,351,194.
`Int. CL6 .......................................................
`G08G 5/04
`[51]
`[52] U.S. CI .............................. 340/961; 342/29; 364/439
`[58] Field of Search ..................................... 340/961, 9"]1,
`340/945; 455/38.1, 115; 342/29, 30, 32.
`36, 37. 38; 364/439, 461,424.06
`
`[56]
`
`References Cited
`
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`
`i mgi II IIIII Hill ill IIIII III llll IHI IIII illn I all ill
`5,714,948
`Feb. 3, 1998
`
`US005714948A
`[11] Patent Number:
`[451 Date of Patent:
`
`1985 Derwent Publications Ltd., Abstract "Location and
`waiting time indicator esp. for buses---has bus-stop tran-
`sponders linked to telephone network and buses which emit
`signals corresponding to location".
`
`Avionics, Business & Commercial Aviation, May 1993, pp.
`168-172.
`
`Benenson, T., "GPS Test: Five Leading Aviation Hand-
`-Helds Go Head-to-Head," Flying, Feb. 1994,
`
`"Flight Tests Highlight New GPS Uses, Emphasize Need for
`GPS/Glonass System".
`
`(List continued on next page.)
`
`Primary Examiner--Brent A. Swarthout
`Attorney, Agent, or Firm~Fish & Richardson EC.
`
`[57]
`
`ABSTRACT
`
`A satellite based air traffic control (ATC) system includes an
`aircraft unit on an aircraft and an ATC facility. The aircraft
`unit includes an AAK’TS processor, GPS receivers or other
`satellite receivers, a comparator for comparing the GPS data,
`a two-way radio, and a transmitter and receiver for commu-
`nicating information and data over a data link with the ATC
`facility. The ATC facility includes an ATC computer, a
`two-way radio, a display for displaying aircraft, and a
`transmitter and receiver for communicating information and
`data over the data link, The aircraft transmits aircraft iden-
`tification information, GPS data. aircraft status information,
`and a transmit detect code to the ATC facility to allow the
`ATC to track the aircraft and identify the aircraft commu-
`nicating on two-way radio. The traffic control system and a
`tiight control system utilizing GPS may be used for aircraft
`in the air and on the ground, and may be used for ships,
`boats, automobiles, trains or railroads, and aircraft.
`
`19 Claims, 3 Drawing Sheets
`
`72
`
`-42
`
`Aircraft
`Status
`Sensors
`’,
`.
`A~raf~ ~
`arid .....
`-84~ " Auto~ilot
`t90
`¯ ,
`-- 84
`N~awgatDon~" ~ - [~Servos ~ Warn~g
`
`Aircraft
`Instrumentation
`
`ELECTR~AL POWER
`FLIGHT MANAG~NT SYSTEM
`~TIAL REFERENCE SYSTEM
`AB DATA SYST~
`RADIO ALTIMETER
`INS~NT LANDING SYSTE~
`CENTRAL WARNING SYSTEM
`ENG ~O CREW ALERT~G SYSTEM.
`
`~- 78
`
`24~
`,
`
`~,GPS1 GPS2 ,I
`,~ "
`26 ~’
`
`to AARTS -
`Pro~ess~r 28
`
`~2
`
`-30
`
`BOEING
`Ex. 1021
`
`

`
`5,714,948
`Page 2
`
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`
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`1/1989 MacDoran et al ......................
`2/1989 Namekawa .
`3/1989 Olsen et al .............................
`4/1989 Apsell et al..
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`5/1989 Manion.
`8/1989 D’Avello et al..
`11/1989 Nimura et al ...........................
`11/1989 Matinelli et al ........................
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`1/1990 Sheffer.
`111990 Karkanti .
`1/1990 Joguet et al ............................
`1/1990 Factor et al .............................
`1/1990 DiLttllo et al..
`2/1990 Raghuram et al ......................
`2/1990 Mitchell.
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`3/1990 Apsell et al..
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`5/1990 Tin.
`4/1991 Ferrell .....................................
`
`343/112 TC
`
`307/219
`
`179/15 BS
`455/115
`
`455/115
`
`364/461
`
`342/32
`
`342/352
`
`324/331
`
`364/449
`364t460
`
`340/988
`364/449
`
`4551115
`
`455/115
`
`3,078,834
`3,357A17
`3,455,403
`3,530,846
`3,538,898
`3,633,040
`3,657,720
`3,696,333
`3,718,899
`3,750,166
`3,808,598
`3,824,469
`3,824,595
`3,859,540
`3,870,994
`3,886,515
`4,039,957
`4,105,900
`4,107,675
`4,117,267
`4,176,318
`4,177,466
`4,197,538
`4200,080
`4,236,594
`4,274,156
`4,325,057
`4,345,554
`4,380,050
`4,392,059
`4,454,510
`4,503,525
`4,606,307
`4,622,557
`4,630,289
`4,642,775
`4,673,936
`4,674,454
`4,688,026
`4,688,244
`4,704,735
`4,718,080
`4,736,461
`4,750,197
`4,754,255
`4,794,649
`4,797,677
`4,809,316
`4,814,711
`4,818,998
`4,821,309
`4,835,537
`4,860,336
`4,882,696
`4,884,208
`4,887,064
`4,888,595
`4,891,650
`4,893,240
`4,894,655
`4,896,154
`4,897,642
`4,903,327
`4,9O4,983
`4,905,271
`4,908,627
`4,908,629
`4,910,493
`4,928,778
`5,005,210
`
`5,014~206 5/1991
`5,021,794 6/1991
`6/1991
`5,025,247
`5,025,382
`6/1991
`5,032,g45
`7/1991
`5,043,736
`8/1991
`8/1991
`5,043,903
`10/1991
`5,055,851
`1/1992
`5,081,667
`5,099,245
`3/1992
`4/1992
`5,103,459
`5,109,341
`4/1992
`5/1992
`5,111,400
`6/1992
`5,119,102
`10/1992
`5,153,836
`12/1992
`5,168,451
`3/1993
`5,197,009
`5/1993
`52O8,59O
`5/1993
`5,208,591
`5/1993
`5,208,756
`511993
`5,210,534
`5/1993
`5,212,812
`6/1993
`5,216,429
`5,216,611
`6/1993
`6/1993
`5,218,367
`5,218,629
`6/1993
`6/1993
`5,221,925
`5223,844
`6/1993
`9/1993
`5,243,529
`5,247,564
`9/1993
`4/1994
`5,301,368
`511994
`5,311,197
`6/1994
`5,325,302
`8/1994
`5,334,974
`9/1994
`5,351,194
`11/1994
`5,361,212
`11/1994
`5,364,093
`1/1995
`5,379,224
`1/1995
`5,381,140
`5,388,047
`2/1995
`9/1996
`5,554,990
`
`Sctibner et al..
`Lawreaee.
`Banks.
`Artz ........................................
`Velaseo.
`Damell et al..
`Constant.
`Sheffer.
`Droti et al..
`Sagey.
`Gilhousen et al..
`Blackburn et al..
`Yoder ......................................
`Barnard .
`Franghton et al..
`Bolger.
`Hoffman, Jr. et al..
`Pitts.
`Ybarra et al ............................
`Song.
`Janex ......................................
`Dutton ....................................
`Nakagawa et aL .
`McHreath ...............................
`Sheffer et aL.
`Dumond, Jr..
`Cross.
`Mansell el al..
`Kashiwazaki
`Zicker.
`
`364/439
`
`364/439
`
`340/961
`
`340/984
`455/115
`
`364/454
`
`Sordea el al.
`Izidon et al .............................
`Simms et al..
`Ross et al ...............................
`Class el al ..............................
`Huston el al .........................
`Brown et al ............................
`Kuroda et al ...........................
`Ryan et al ..............................
`McKinney ................................
`
`364/461
`
`364/449
`364/428
`273/32 R
`364/449
`340/961
`364/461
`342/36
`
`OTHER PUBLICATIONS
`
`Nordwall, B.D., Aviation Week and Space Technotog?g
`135:22, p. 17, Dec. 2. 1991.
`"GPS Demonstration Results Push System into Forefront for
`Airport Traffic Plan".
`Chapman Security Systems. Inc. (Bensenville, Illinois),
`"Chapman 911Capital Litigation Support," Product Cata-
`logue, undated, 4 pgs.
`Connes, K., "GPS," Plane & Pilot, pp. 22-24, Aug. 1994.
`Delta Air Lines "Cat ~ Operations--Technical Opera-
`tions Training Course #401," Apr. 6, 1990.
`Delta Air Lines Flight Operations Policy Manual, Jan. 29,
`1993.
`Gilbert, C., "Obtaining Real-time Differential Data from
`Government Sources," Earth Observation Magazine, Nov./
`Dec. 1993.
`International Telelrac Systems, "Have an Unfair Advantage
`Over Car Thieves", Advertising Flyer, 1990. 3 pages.
`International Teletrac Systems, "How to Put Your Fleet on
`the Map", Advertising Flyer, undated, 5 pages.
`Klass, P.J., A viaaon Week and Space Technology, 135:24/25,
`p. 42, Dec. 23, 1991.
`Klass, Phih’p J., "Airline Officials Foresee Quick Growth in
`Use of GPS, Glonass on Commercial Transports", Aviation
`Week and Space Technology, Jun. 29, 1992, page 54.
`
`BOEING
`Ex. 1021
`
`

`
`5,714,948
`Page 3
`
`Klass. Philip J.. "FAA Steps Up Program to Introduce GPS
`as Instrument Approach Aid", Aviation Week and Space
`Technology, Aug. 17, 1992, pp. 35-36.
`Klass, Philip J.. "GPS Demonstration Results Push System
`Into Forefront for Airport Traffic Plan", Aviation Week and
`Space Technolog)¢ Dec. 16, 1991. page 42.
`Logsdon, T., The Navstar Global Positioning System, Van
`Nostrand Reinhold, 1992.
`Magnavox Advanced Products and Systems Company
`(Advertising Flyer), "Presenting the Most Advanced AVLS
`Available," 1988.6 pages.
`Meluso. D., "Accuracy Guaranteed," Boating, Sep., 1993.
`Mets. Inc. (Indianapolis, Indiana), "Public Safety Police,
`Fire and Emergency Medical Services", 1989, 4 pages.
`Mets, Inc. (Indianapolis, Indiana), ’~l’rucking National &
`Regional Fleet Control", 1989, 4 pages.
`Morgen-Walke Associates, Inc. News Release "Trimble
`Announces New Generation of GPS Marine Products," Jan.
`5, 1994, London, U.K.
`Nordwall. B.D., "Flight Tests Highlight New GPS Uses,
`Emphasize Need for GPS/Glonass System", Aviation Week
`and Space Technology, Dec. 2. 1991, p. 71.
`Nordwall, B.D., "Imagination Only Limit to Military, Com-
`mercial Applications for GPS", Aviation Week and Space
`Technology, Oct. 14, 1991, p. 60.
`Nordwall, B.D.. "Low Price, New Ideas Fuel GPS Growth",
`Aviation Week and Space Technology, Nov. 30, 1992, p. 48.
`
`Trimble Navigation (Sunnyvale, California). "Fleetvision
`Integrated Fleet Management System", undated, 9 pages.
`Trimble Navigation (Sunnyvale, California). "Starfmder
`GPS Intelligent Mobile Sensor", 1991, 2 pages.
`Trimble Navigation (Sunnyvale, California), "Starview
`Tracking and Display Station", undated, 1 page.
`Trimble Navigation (Sunnyvale. California), "Trimble’s
`GPS/AVL Continues to Dominate Public Safety Market,"
`Press Release, Feb. 7, 1994.
`Trimble Navigation, "FleetVision--Integrated Fleet Man-
`agement System," (undated).
`Trimble, "The 9th Utility" Advertisement.
`U.S. DOT, FAA; 6560.14A Order, "Project Implementation
`Plan for the Digital Altimeter Setting Indicator (DASI)
`Program," Nov. 10. 1993.
`U.S. DOT. FAA; 6690.4 Order, "project Implementation
`Plan Voice Switching and Control Systera." Oct. 25, 1993.
`U.S. DOT, FAA; 7110.10K CHG 2, re Flight Services, May
`28, 1994.
`U.S. DOT, FAA; 7110.65H CHG 1. re Air Traflice Control.
`Nov. 4, 1993.
`U.S. DOT. FAA; 7110.65H CHG 2, re Air Traffic Control.
`Feb. 4, 1994.
`U.S. DOT, FAA; 7210.3K CHG 1, re Facility Operation and
`Administration. Oct. 4, 1993.
`Westinghouse (Baltimore, Maryland), "Vehicle Manage-
`ment Systems", Product Catalogue. undated, 4 pages.
`
`BOEING
`Ex. 1021
`
`

`
`U.S. Patent
`
`Feb. 3, 1998
`
`Sheet 1 of 3
`
`5,714,948
`
`18
`
`to AARTS
`Processor 2~ /
`26-~
`
`PS~ I
`
`D
`
`I~’~-I~1~1
`
`~
`GPS
`IRS
`r,
`_~--J[~
`/ I~l~-J_~l~l /24
`
`] to AARTS
`Processor 28
`~31
`memory-
`
`//" N0rmal~
`(*
`t A~
`
`~
`
`-
`-
`GPS Data Comparator
`
`~ STARS
`
`~Processor
`
`46 m mor ~
`/c - em°ry
`t r an~ mi~ ~ ~
`~det~c~ -
`!
`~44
`~ ~ ___~ ~~mory ~40
`
`Display y39
`
`Input
`"
`
`II ~’~uE=’=l
`
`~ ~craft
`/
`~
`~
`
`2-Way
`Radio
`
`I =~--~ta I’, ’,1
`~_._ II 42
`, = -
`uu~
`_ .
`IF i~="~" 1~32
`’~ Detector
`~
`37-,
`~
`.P36
`~, ’,
`33~Demodulator~,, Modulator ~
`35~ =’,
`’, Receiver ’~’, Transmitter
`
`Fig. 1
`
`BOEING
`Ex. 1021
`
`

`
`BOEING
`EX. 1021
`
`BOEING
`Ex. 1021
`
`

`
`U.S. Patent
`
`Feb. 3, 1998
`
`Sheet 3 of 3
`
`5,714,948
`
`BOEING
`Ex. 1021
`
`

`
`1
`SATELLITE BASED AIRCRAFT TRAFFIC
`CONTROL SYSTEM
`
`CROSS REFERENCE TO RELATED
`APPLICATIONS
`This application is a continuation of application Ser. No.
`08/275,547, filed on Jul. 15, 1994, now abandoned which is
`a continuation-in-part of application Ser. No. 08/062,406
`filed on May 14, 1993, now U.S. Pat. No. 5,351,194 issued
`on Sep. 27, 1994.
`
`BACKGROUND OF THE INVENTION
`The invention relates to a system for the tracking and
`control of aircraft and other vehicles and the communication
`between aircraft and traffic controllers, and specifically to a
`satellite based system for tracking, guiding, controlling and
`communicating with aircraft and vehicles in the air, in the
`water and on the ground.
`Present air traffic control systems consist of a network of
`terminal area and enroute surveillance radar systems. These
`systems consist of both primary and secondary radar sys-
`tems and computers that display usable data for the control
`of air traffic in the national and international airspace sys-
`tems.
`The basic radar system consists of Primary Radar which
`operates by transmitting a pulsed radio signal at a known
`azimuth (direction. in degrees from North) from the radar
`antenna and measures the time it takes to receive the
`reflected signal from an object (aircraft) in space back to the
`point of transmission. This time factor determines the range
`in nautical miles from the radar site and the direction is
`determined by the azimuth from which the signal is
`received. The limitations of using only this system result in
`the loss of targets because of the difficulty in detecting weak
`reflected radar return signals attenuated by atmospheric
`conditions.
`Secondary radar, known as the Air Traffic Control Radar
`Beacon System (ATCRBS), utilizes cooperative equipment
`in the form of radio receiver/transmitter (Transponder).
`Radar pulses transmitted from the searching radar transmit-
`ter interrogate the airborne transponder. In response to
`receiving the interrogating signal from the radar, the Tran-
`sponder transmits a distinctive signal back to the Radar
`Beacon System’s antenna. For example Delta flight 195 to
`Dallas (Dal195) is requested to squawk "4142," resulting in
`the aircraft transponder being dialed to code "4142." The
`computer at the air traffic control (ATC) facility is prepro-
`grammed to understand that transponder code "4142" cor-
`responds to Da1195. The signal transmitted by the Transpon-
`der is typically coded to provide both aircraft altitude and
`aircraft identification data (4142) for processing by the air
`traffic controller’s computer for display on the air traffic
`controller’s radar scope. The aircraft’s transponder is con-
`nected to an altitude encoder which encodes altitude data
`based on the altitude of the aircraft as determined from the
`aircraft altimeter. In addition, the aircraft’s speed is pres-
`ently determined by the ATC computer by measuring the
`time and distance differences from subsequent transmissions
`of the Transponder. The aircraft transponder code, altitude,
`and speed may be displayed on the controller’s radar screen.
`However, present radar-based air traffic control systems
`suffer from a number of disadvantages and drawbacks.
`Radar systems, even when used in conjunction with sec-
`ondary radar, provide limited range and accuracy in the
`determination of the location and altitude of an aircraft. The
`range of radar is inherently limited due to obstacles in the
`
`5,714,948
`
`2
`line of sight of the radar, curvature of the earth, atmospheric
`conditions, etc. Search radar has a range of approximately
`300 to 350 nautical miles, while terminal radar is utilized
`only for about 30 nautical miles. Radar coverage is not
`5 available in many areas of the world, and is not available at
`all altitudes in the United States.
`Presently, radar is also used to track and determine the
`location of aircraft on the ground One current system is
`known as the Airport Surface Detection Equipment (ASDE),
`10 which is a high resolution radar system with a tower
`mounted radar antenna that "looks" down on the airport
`surface. This system tracks aircraft on the surface to a given
`altitude, for example from the surface to an altitude of 185
`feet. This type of surface detection system has a number of
`15 disadvantages, including: a prohibitively high cost. aircraft
`targets are not tagged (location of aircraft is identified only
`by radio communications), the system produces split (ghost)
`targets, buildings and hangars restrict the view of some
`portions of the airport surface, high sensitivity of the system
`2o resulting in long periods of downtime for maintenance, and
`the system is not interfaced with departure controllers
`requiring the landing aircraft to be off the parallel runway
`before the departing aircraft can be released. Keeping track
`of the exact location of aircraft is important in low visibility
`25 conditions and enables controllers to expedite the flow of
`traffic.
`In addition, the present communication process between
`affcraft and air traffic controllers is standardized, however, it
`is inherently subject to errors or miscommunlcations.
`30 Presently. air traffic controllers and aircraft exchange infor-
`marion and communicate orally (verbally) via two-way
`radio. Therefore. with the exception of information obtained
`via primary and secondary radar, all information from the
`aircraft regarding the aircraft’s status (i.e.. aircraft is okay.
`35 emergency condition, equipment malfunction), the aircraft’s
`speed, heading, and identification of the aircraft, and inslruc-
`tions from the air traffic controller are communicated ver-
`bally via two-way radio. Thus, the exchange of accurate
`information between the air traffic controller and the aircraft
`40 is dependent upon hearing, understanding and recording a
`clear verbal communication via two-way radio. This reli-
`ance upon human hearing and interpretation during the
`communications process provides an inherent oppottunlty
`for errors or miscommunication and complicates the air
`45 traffic controller’s job, particularly in light of the back-
`ground and engine noise present on aircraft, poor radio
`performance or unclear speech.
`Such miscommunication between flight crews and air
`traffic controllers can lead to serious problems. A controller
`50 may be giving instructions to the pilot of one aircraft on his
`radar screen and obtain an acknowledgement of the instruc-
`tions from a pilot of another aircraft with a similar call sign
`or flight number. The only true verification that the correct
`aircraft received the instructions is a verbal verification of
`55 the correct call sign. or by observance by the controller that
`the aircraft called responded correctly to the instructions. If
`the wrong aircraft (or multiple aircraft) comply with the
`instructions and several aircraft are on the controller’s
`screen, it may be ditficult for the controller to recognize the
`6o error and safety can easily be compromised. Another com-
`mon communication problem a controller may encounter is
`receiving an initial call from an aircraft and having difficulty
`identifying the corresponding aircraft on his radar screen.
`This is prevalent with the current system since all aircraft
`65 operating under Visual Flight Rules ("VFR") emit the same
`transponder code (1200). While standard codes emitted by a
`transponder are understood to communicate specific
`
`BOEING
`Ex. 1021
`
`

`
`5,714,948
`
`4
`an aircraft landing system that does not rely on localizer and
`glideslope transmitters.
`
`3
`information, such as transponder code "7600" indicates
`radio failure, and code "7700" indicates an emergency, such
`transponder (radar) communication provides very limited
`SUMMARY OF THE INVENTION
`communication of information (limited types of messages
`and only one message/communication at a time) and only
`5 The traffic control system of the invention meets these
`operates in a radar environment.
`needs and overcomes the disadvantages and drawbacks of
`Alternative ATC systems have been proposed that would
`the prior art by providing an aircraft unit on board an aircraft
`use the global positioning satellites (GPS). Such a proposed
`and an air traffic control (ATC) facility that communicate via
`alternative is discussed in chapter 12 of Logsdon, The
`data link. The aircraft unit includes an ATC Aircraft Report-
`10 ing and Tracking System (AARTS) processor for controlling
`Navstar Global Positioning System, Von Neistrand Reinhold
`(1992). In The Navstar Global Positioning System, Logsdon
`operations of the aircraft unit, GPS receivers for determining
`discusses the proposed use of GPS receivers on board
`the aircraft’ position, trace altitude, and speed, a GPS data
`aircraft, wherein the aircraft transmits its GPS aircraft vector
`comparator for comparing the GPS data, a two-way radio,
`to air traffic controllers for display on the air trat~c control-
`and a transmitter and receiver for transmitting and receiving
`15 (communicating) data and other information over a data
`lers’ screen. However, Logsdon’s discussion fails to provide
`any details of such a system or how it could be implemented.
`link, Data that are communicated may include GPS data
`Furtheawaore, Logsdon’s proposal does not address ground
`(altitude, position, heading and speed) and aircraft identifi-
`or surface detection of aircraft. Also, the Logsdon proposal
`cation data (registration number, flight number, etc.), while
`fails to address the need for improved communication of
`other information communicated may include aircraft status
`2o information, requests, questions, responses, fight
`information between aircraft and air traffic controllers, and
`the need for a technique to identify the aircraft that is
`instructions, landing instructions, flight path information,
`communicating with the air traffic controller.
`information concerning conflicting aircraft, etc.
`Furthermore, present aircraft navigation and precision
`The ATC facility includes a transmitter and receiver for
`landing systems have a number of disadvantages. In the 48
`25 transmitting and receiving an information transmission
`contiguous United States, most instrument navigating is
`(comprising data and other information) over the data link,
`done with the aid of a VHF Omnidirectional Range (VOR)
`a data decoder/detector for detecting data and communica-
`receiver for using the VHF radio signals emitted by the
`tions in a received information transmission, a two way
`ground based VOR transmitters. Virtually all enroute navi-
`radio, an ATC computer for controlling operations at the
`gation and many instrument approaches use these signals,
`30 ATC facility and identifying received data and
`which are broadcast in the frequency range 108,0 to 119.0
`communications, and a display for displaying the location
`Mhz. The VOR signal is a blinking omnidirectional pulse,
`and status of aircraft. Aircraft periodically transmit identi-
`and has two parts: a reference phase signal and the variable
`fication information, their GPS position, track, speed, and
`phase signal. It its transmitted in such a way that the phase
`altitude, their status, and other information to the ATC
`between these two signals is the same as the number of
`35 facility. Based on this received information, the ATC facility
`degrees the receiving aircraft is from the VOR station. The
`continuously monitors and tracks aircraft. Because each
`VOR receiver and equipment uses the signals to determine
`aircraft transmits a different and predetermined
`its magnetic direction, or course, from the VOR.
`identification, the ATC facility knows the identity of each
`An additional navigation aide is known as Direction
`target on the ATC controller’ s display. This system provides
`Measurement Equipment (DME). DME uses two-way
`40 the additional advantage of allowing the ATC to accurately
`(interrogation and reply) active spherical ranging to measure
`track aircraft without using radar, thereby avoiding the
`the slant range between the aircraft and the DME transmit-
`problems and disadvantages of radar, such as ghosts, limited
`ting station. Many pilots and navigators vector airplanes
`range due to curvature of the earth and fine-of-sight
`from waypoint to waypoint using the signals from VOR/
`problems, etc. Furthermore, the tracking system of the
`D/VIE. rather than traveling in a straight fine. As a result,
`45 invention may operate even in areas where no radar cover-
`aircraft are not traveling the shortest distance, causing
`age is available. Also, the communication of requests,
`increased fuel usage and increased travel time. Also, routes
`responses, information and data over a data link between
`along the VOR/DME stations become heavily traveled
`aircraft and the ATC facility provides more accurate and
`resulting in increased probability of mid-air collisions.
`complete communications than two-way radio, and avoids
`50 any miscornmunications or misinterpretation of speech that
`In addition, many aircraft employ so-called Instrument
`commonly occur with two-way radio.
`Landing Systems 0LS) for performing precision landings.
`ILS includes several VHF localizer transmitters that emit
`In addition, the aircraft unit also includes a transmit
`focused VHF signals upwardly from the airport to provide
`detector for detecting when the aircraft’s two-way radio is
`horizontal guidance to the aircraft and its autopilot systems.
`transmitting. The ATC facility receives the transmit detect
`ILS also includes a UHF glideslope transmitter that radiates
`55 code along with the aircraft’s identification via data link.
`a focused UHF signal that angles downwardly across the
`thereby indicating when the aircraft’s two-way radio is
`runway to provide veRicai guidance. While ILS provides an
`transmitting. This code may be displayed on the controller’s
`effective technique for precision landings, such ILS preci-
`display and afiows the controller to identify or confirm
`sion landings are not possible where the airport does not
`exactly which aircraft on his screen/display he is commu-
`include such loealizer and glldeslope transmitters.
`60 nicating verbally over the two-way radio.
`The foregoing demonstrates a need for an improved air
`The system of the invention may be used to track aircraft
`and ground traffic control systems for aircraft. There is also
`in the air or on the ground. The ATC facility may include a
`pseudo-satellite, or a GPS receiver that acts as a base station
`a need for improved communication and exchange of infor-
`to allow aircraft GPS receivers to operate in differential
`mation between aircraft and air traffic controllers, and a need
`for a system that allows controllers to verify the communi-
`65 mode. In differential mode, the ATC facility determines the
`cating aircraft, There is also a need for an effective naviga-
`GPS pseudo-range correction by subtracting the geomeWic
`tion system that does not rely on VOR/DME stations, and for
`range (based on the facility’s known location) from the
`
`BOEING
`Ex. 1021
`
`

`
`pseudo-range (calculated using GPS signals). This correc-
`lion may be used by the aircraft or the base station to obtain
`much more accurate aircraft positioning.
`Each aircraft may include a flight control system for
`automating the flight and navigation of the aircraft. The 5
`flight control system includes a flight control computer for
`controlling the operation of the flight control system, GPS
`receivers, and a control panel. The flight control computer is
`connected to various aircraft interfacing systems, aircraft
`instrumentation, aircraft sensors, external navigation aids, 10
`and autopilot servos and servo drives. In an autopilot mode,
`the flight control computer automatically controls the air-
`craft to fly on a predetermined flight path. The flight control
`computer uses GPS data, and may use signals from external
`navigation aids and aircraft sensors to navigate the aircraft 15
`on the predetermined flight path. The aircraft may perform
`a precision (automatic) landing in the autoland mode using
`only GPS data, and preferably differential GPS data, rather
`than relying on the localizer and glideslope at the airport.
`The systems and methods of the invention may also be used 20
`on other vehicles, such as ships, boats, automobiles, and
`railroads.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a block diagram of an aircraft unit constructed
`according to the principles of the invention.
`FIG. 2 is a block diagram of an air traffic control facility
`constructed according to the principles of the invention.
`FIG. 3 is a block diagram of a flight control system 30
`constructed according to the principles of the invention.
`
`25
`
`DETAILED DESCR.1FFION
`
`Air Traflfic Control System 35
`Referring to the drawings in detail, wherein like numerals
`indicate like elements, FIGS. 1-2 show the overall structure
`of a satellite based air traffic control (ATC) system according
`to the principles of the invention. FIG. 1 illustrates an
`aircraft unit 18 of the ATC system. FIG. 2 illustrates an ATC 40
`fadlity 48 of the satellite based ATC system according to the
`prindples of the invention.
`Referring to FIG. 1, aircxaft unit 18, which is fixed to a
`conventional aircraft platform, includes dual global posi-
`tioning system ("GPS") receivers 20 and 22 for determining 45
`the aircraft’s position (longitude, latitude), speed, altitude,
`and tracking. Other types of satellite receivers, such as
`receivers for receiving signals from the Soviet Glonass
`satellites, may be used. As well understood by those skilled
`in the art, each GPS satellite transmits binary pulse trains, 50
`copies of which are created in the GPS receiver electronics.
`The GPS receiver antenna detects the signals (binary pulse
`trains) transmitted from GPS satellites, amplifies the
`received signals, and inputs them into two tracking loops
`that lock onto the carder waves. The GPS pulse train is 55
`adjusted in the tracking loop until it is brought into corre-
`spondence with the satellite pulse train. When correspon-
`dence is achieved, the GPS receiver resident processor can
`determine time signal travel time based on the pulse adjust-
`ment. The GPS receiver resident processor then may deter- 6o
`mine the pseudo-range (distance from the GPS receiver to
`each satellite) based on the signal travel time (plus or minus
`clock bias error) multiplied times signal travel time;
`(pseudo-range=Cxdelta T). The GPS receiver may then
`determine its location using four pseudo-ranges, solving 65
`four simultaneous equations having four unknowns (dock
`bias error drops out), as well known to those skilled in the
`
`5,714,948
`
`6
`art. The GPS receiver resident microprocessor automatically
`determines the user’s current position (longitude. latitude),
`altitude, tracking and speed (navigation solution).
`Each GPS receiver should be a multi-channel receiver for
`receiving positioning signals from a plurality of GPS satel-
`lites. A number of GPS receivers are commercially available
`from such companies as Sony Corporation, Motorola. Rock-
`well International (the Naveore V GPS receiver), and others.
`One such commercially available GPS receiver is the Nay
`1000 GPS receiver manufactured by Magellan Systems
`Corporation. The dam output by GPS receivers 20 and 22 are
`output to GPS data comparator 24.
`In a large commercial aircraft, GPS receivers 20 and 22
`should be placed at opposite ends of the aircraft, for
`example, 100 feet apart. In large or small aircraft, the GPS
`receivers may alternatively be placed side-by-side. GPS data
`comparator 24 compares the data (location, altitude, speed,
`tracking) from both GPS receivers.
`GPS receiver switch 26 is connected to comparator 24 and
`allows the selection of eomparator 24 into one of three
`modes: 1) normal mode, 2) GPSI. and 3) GPS2. In the
`normal mode. comparator 24 compares the GPS data from
`the two GPS receivers 20, 22, to ensure that the data from
`these two receivers are reasonable compared to each other
`based on the distance separating the two receivers 20 and 22.
`In the normal mode, for example, GPS data comparator 24
`may compare the data between the first and second GPS
`receivers 20 and 22 to determine whether the data from the
`first GPS receiver 20 is within a predetermined range of the
`data of the second GPS receiver 22. This GPS data from both
`GPS receivers is then output to the ATC Aircraft Reporting
`and Tracking System (AAR’FS) processor 28. The AARTS
`processor 28 controls the overall operation of the aircraft
`unit 18 of the ATC system and is discussed in greater detail
`hereinbeiow. The GPS integrity line 25 from comparator 24
`indicates whether the GPS data output by compar