Fixed curved path waypoint transition for aircraft
First Claim
1. An apparatus for transitioning an aircraft from an inbound course to an outbound course of a waypoint, said waypoint surrounded by a regulated band of airspace within which a travel of inbound and outbound air traffic is constrained to fly, said apparatus comprising:
- a. curved path means for computing a fixed circular transition path from said inbound course to said outbound course, said transition path being tangential to said inbound and said outbound courses,b. bank bias means for generating a bank angle command signal for maintaining said aircraft on said fixed circular path,c. deviation means generating deviation correction signals with respect to said fixed circular path for constraining said aircraft to fly along said fixed circular path in transitioning from said inbound to said outbound course, andd. altitude signal generating means for generating an altitude signal representative of the altitude of said aircraft, wherein said curved path means comprises,maximum cross track error means for generating a maximum cross track error signal representative of a maximum deviation allowable from said inbound and outbound courses based on said altitude signal,turn radius means generating a turn radius signal for said fixed circular path in accordance with said maximum cross track error signal,turn center means generating turn center signals, for said fixed circular path, andangular position means responsive to said turn center signals for generating an angular position signal representative of the angular position of said aircraft on said fixed circular path.
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Accused Products
Abstract
Control apparatus for an aircraft area navigation system provides transitioning from an inbound leg to an outbound leg of a lateral navigation waypoint with a fixed curved transition path with or along the outer limit of the protected airspace width or PAW. The present invention determines in conjunction with the aircraft altitude and the angle of the course change a maximum distance that the aircraft will deviate from either the inbound or outbound leg. This distance is sometimes called the maximum cross track error or MXTK. The maximum cross track error information in conjunction with the course change angle is used to generate a turn radius for a fixed curved transition path to be followed by the aircraft independent of ground speed. The turn radius information together with the aircraft ground speed information is used to generate a bank angle bias command signal. The bank angle bias command is calculated to vary the bank angle of the aircraft so as to keep the aircraft on the fixed curved path throughout the transition from outbound to inbound waypoint legs.
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Citations
24 Claims
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1. An apparatus for transitioning an aircraft from an inbound course to an outbound course of a waypoint, said waypoint surrounded by a regulated band of airspace within which a travel of inbound and outbound air traffic is constrained to fly, said apparatus comprising:
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a. curved path means for computing a fixed circular transition path from said inbound course to said outbound course, said transition path being tangential to said inbound and said outbound courses, b. bank bias means for generating a bank angle command signal for maintaining said aircraft on said fixed circular path, c. deviation means generating deviation correction signals with respect to said fixed circular path for constraining said aircraft to fly along said fixed circular path in transitioning from said inbound to said outbound course, and d. altitude signal generating means for generating an altitude signal representative of the altitude of said aircraft, wherein said curved path means comprises, maximum cross track error means for generating a maximum cross track error signal representative of a maximum deviation allowable from said inbound and outbound courses based on said altitude signal, turn radius means generating a turn radius signal for said fixed circular path in accordance with said maximum cross track error signal, turn center means generating turn center signals, for said fixed circular path, and angular position means responsive to said turn center signals for generating an angular position signal representative of the angular position of said aircraft on said fixed circular path. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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4. The apparatus of claim 2 further including,
a. VOR/DME computing means for providing first position signals representative of the position of said aircraft with respect to a VOR/DME station, b. waypoint computing means for providing second position signals representative of the position of said waypoint with respect to said VOR/DME station, and c. combining means responsive to said first and second position signals and said turn center signals for providing further position signals representative of the position of said aircraft with respect to said turn center, d. said angular position means being responsive to said further position signals for generating said angular position signal. -
5. The apparatus of claim 4 in which said combining means comprises,
a. first combining means for combining said first and second position signals for providing third position signals representative of the position of said aircraft with respect to said waypoint, and b. second combining means for combining said third position signals and said turn center signals for providing said further position signals. - 6. The apparatus of claim 5 in which
a. said difference means comprises means for computing the function - space="preserve" listing-type="equation">dU=U.sub.2 -U.sub.1
b. said distance means comprises means for computing the function
space="preserve" listing-type="equation">F.sub.7 =D=TR tan (dU/2)and c. said turn center computing means comprises means for computing the function
space="preserve" listing-type="equation">NTCW=-D cos U.sub.1 -TR sin U.sub.1
space="preserve" listing-type="equation">ETCW=-D sin U.sub.1 +TR cos U.sub.1where U1, U2 =said inbound and outbound courses respectively dU=said difference signal TR=said turn radius signal D=said distance signal NTCW, ETCW =said turn center signals representing the north and east coordinates of said turn center with respect to said waypoint respectively.
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- 7. The apparatus of claim 6 in which
a. said VOR/DME computing means comprises means for providing first position signals NAV and EAV representative of the north and east coordinates respectively of said position of said aircraft with respect to said VOR/DME station, b. said waypoint computer means comprises means providing second position signals NWV and EWV representative of the north and east coordinates respectively of said position of said waypoint with respect to said VOR/DME station, c. said first combining means comprises means for computing the function - space="preserve" listing-type="equation">NAW=NAV-NWV
space="preserve" listing-type="equation">EAW=EAV-EWVand d. said second combining means comprises means for computing the function NTCA =NTCW-NAW ETCA =ETCW=EAW where NAW, EAW=said third position signals representing the north and east coordinates respectively of said position of said aircraft with respect to said waypoint and NTCA, ETCA =said further position signals representing the north and east coordinates respectively of said position of said aircraft with respect to said turn center.
- space="preserve" listing-type="equation">F.sub.9 =T.sub.1 =tan.sup.-1 (NTCA/ETCA)
- space="preserve" listing-type="equation">F.sub.11 =XTK=TR-(NTCA.sup.2 +ETCA.sup.2).sup.1/2 for clockwise turns, or
space="preserve" listing-type="equation">F.sub.11 =XTK=(NTCA.sup.2 +ETCA.sup.2).sup.1/2 -TR for counterclockwise turns
space="preserve" listing-type="equation">F.sub.10 =TKE=(T+90°
)-TA for clockwise turns
space="preserve" listing-type="equation">F.sub.10 =TKE=(T-90°
)-TA for counter clockwise turns
space="preserve" listing-type="equation">P.sub.c =P.sub. +k.sub.1 XTK+k.sub.2 TKE
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18. An apparatus for transitioning an aircraft from an inbound course to an outbound course of a waypoint, said waypoint surrounded by a regulated band of airspace within which a travel of inbound and outbound air traffic is constrained to fly, said apparatus comprising;
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a. curved path means for computing a fixed circular transition path from said inbound course to said outbound course, said transition path being tangential to said inbound and said outbound courses, b. bank bias means for generating a bank angle command signal for maintaining said aircraft on said fixed circular path, c. deviation means generating deviation correction signals with respect to said fixed circular path for constraining said aircraft to fly along said fixed circular path in transitioning from said inbound to said outbound course, d. altitude signal generating means for generating an altitude signal representative of the altitude of said aircraft, e. means for generating a zone designation signal based on said altitude signal, and f. means for generating a course change signal representative of a course angle change between said inbound and outbound courses means for combining said zone designation signal and said course signal for generation a maximum cross track error signal representative of a maximum deviation allowable from said inbound and outbound courses based on said altitude signal. - View Dependent Claims (19, 20, 21, 22, 23)
- 21. The apparatus of claim 20 wherein said means for generating said maximum cross track error signal include means for computing the function
- space="preserve" listing-type="equation">F.sub.12 =MXTK=k.sub.3 (dU) if ZDS =EZ
space="preserve" listing-type="equation">F.sub.12 =MXTK=k.sub.4 (dU) if ZDS =TZwherein MXTK=maximum cross track error signal ZDS=zone designation signal EZ=enroute altitude zone TZ=terminal altitude zone k3 =constant for enroute altitude zone k4 =constant for terminal altitude zone dU=angle of inbound and outbound course change
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- 22. The apparatus of claim 21 wherein said means for generating said turn radius signal includes means for computing the function
- space="preserve" listing-type="equation">F.sub.16 =TR=MXTK/[1--cosine (dU/2)]
wherein TR=turn radius MXTK=maximum cross track error signal dU=course change angle
- space="preserve" listing-type="equation">F.sub.15 =P.sub.m =arc tangent [VG·
VG/(TR·
g)]
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24. An area navigation system for transitioning an aircraft along a track from an inbound course to an outbound course of a area navigation waypoint, said waypoint surrounded by a protected airspace width within which the travel of inbound and outbound air traffic is constrained to fly, said apparatus comprising;
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a. means for generating an altitude signal representative of the altitude of said aircraft, b. means for generating a velocity signal representative of said aircraft ground speed, c. means for generating a course change signal representative of a course angle change between said inbound and outbound courses, d. means utilizing said altitude signal for generating a zone designation signal representative of an enroute or terminal zone of said aircraft, e. means combining said course change signal and said zone designation signal for generating a maximum cross track error signal representative of a maximum distance that an aircraft will deviate from an inbound course or outbound course, f. means combining said course change signal and said maximum cross track error signal for generating a turn radius signal representative of the radius required for said aircraft to fly a fixed curved path along said track within said protected airspace width, g. means combining said course change signal and said turn radius signal for generating a distance signal representative of the distance from said waypoint to a point of tangency of said fixed curved path on said inbound course, h. means combining said turn radius signal and said velocity signal for generating a bank angle bias command signal representative of the bank angle of said aircraft flying along said fixed curved path.
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Specification