US4933668A — Aircraft security system

Claim 1

Independent Claim 185 words

An aircraft signalling system comprising: a central control unit including an onboard computer and a dc power source; one or more cluster controllers, each remotely located from said central unit and including a microprocessor; a plurality of sensors associated with and controlled by each cluster controller; a two-wire bus connecting said central unit and said cluster controllers, said bus carrying dc operating power from said power source to said cluster controllers and said plurality of sensors and carrying digital data signals in both directions between said onboard computer and said cluster controllers, said data signals including positive-going transitions and negative-going transitions between binary logic levels; said central control unit further including first interface means for interfacing said dc power and digital data signals to said two-wire bus; and said cluster controllers each further including second interface means for interfacing said dc power and digital data signals to said two-wire bus, said first interface means and said second interface means each including means responsive to said positive-going transitions and said negative-going transitions in digital data signals received on said bus for reconstructing said digital data signals.

Claim 2

Dependent Claim 185 words

An aircraft signalling system comprising: a central control unit including an onboard computer and a dc power source; one or more cluster controllers, each remotely located from said central unit and including a microprocessor; a plurality of sensors associated with and controlled by each cluster controller; a two-wire bus connecting said central unit and said cluster controllers, said bus carrying dc operating power from said power source to said cluster controllers and said plurality of sensors and carrying digital data signals in both directions between said onboard computer and said cluster controllers, said data signals including positive-going transitions and negative-going transitions between binary logic levels; said central control unit further including first interface means for interfacing said dc power and digital data signals to said two-wire bus; and said cluster controllers each further including second interface means for interfacing said dc power and digital data signals to said two-wire bus, said first interface means and said second interface means each including means responsive to said positive-going transitions and said negative-going transitions in digital data signals received on said bus for reconstructing said digital data signals.

Claim 3

Dependent Claim 64 words

An aircraft signalling system as defined in claim 1 wherein said first interface means comprises a transformer having two secondary windings and said power source comprises a voltage source connected in series between said two secondary windings, said two-wire bus being connected across the series combination of said two secondary windings and said voltage source such that said voltage is carried on said bus.

Claim 4

Dependent Claim 59 words

An aircraft signalling system as defined in claim 1 wherein said first interface means comprises a first transformer having secondary windings coupled to said bus, first means for coupling said digital data signals between a primary winding of said first transformer and said onboard computer, and first means for coupling said power source to secondary windings of said transformer.

Claim 5

Dependent Claim 64 words

An aircraft signalling system as defined in claim 3 wherein each of said second interface means comprises a second transformer having secondary windings coupled to said two-wire bus, second means for coupling said digital data signals between a primary winding of said transformer and said microprocessor, and second means for coupling power through said secondary windings of said transformer to the respective cluster controller.

Claim 6

Dependent Claim 72 words

An aircraft signalling system as defined in claim 1 wherein each of said second interface means comprises a transformer having two secondary windings and the respective cluster controller includes a voltage regulator connected in series between said two secondary windings, said two-wire bus being connected across the series combination of said two secondary windings and said voltage regulator such that a voltage carried on said bus is supplied to said voltage regulator.

Claim 7

Dependent Claim 110 words

An aircraft signalling system as defined in claim 4 wherein said first digital data coupling means and said second digital data coupling means each comprise means for differentiating digital data signals received on said bus and providing a voltage pulse of one polarity for each positive going transition in said data signals and a voltage pulse of the opposite polarity for each negative going transition in said data signals, and comparator means for providing a first logic level when said voltage pulse of one polarity crosses a first threshold level and for providing a second logic level when said voltage pulse of the opposite polarity crosses a second threshold level.

Claim 8

Dependent Claim 116 words

An aircraft signalling system as defined in claim 6 wherein said first transformer includes two secondary windings, said power source is connected in series between said two secondary windings and said two-wire bus is connected across the series combination of said two secondary windings and said power source such that said voltage is carried on said bus, and each of said second transformers includes two secondary windings and each of said cluster controllers includes a voltage regulator connected in series between said two secondary windings, said two-wire bus being connected across the series combination of said two secondary windings and said voltage regulator such that power carried on said bus is supplied to said voltage regulator.

Claim 9

Dependent Claim 35 words

An aircraft signalling system as defined in claim 3 further including means for monitoring the current supplied on said two-wire bus and for disconnecting said power source therefrom when the current exceeds a prescribed level.

Claim 10

Dependent Claim 33 words

An aircraft signalling system as defined in claim 8 wherein said monitoring means includes means for sensing the voltage across one of said secondary windings to determine the current supplied on said bus.

Claim 11

Dependent Claim 182 words

A signalling system comprising: a central control unit including a computer and a dc power source; one or more cluster controllers, each remotely located from said central unit and including a microprocessor; a plurality of sensors associated with and controlled by each cluster controller; a two-wire bus connecting said central unit and said cluster controllers, said bus carrying dc operating power from said power source to said cluster controllers and said plurality of sensors and carrying digital data signals in both directions between said computer and said cluster controllers, said data signals including positive-going transitions and negative-going transitions between binary logic levels; said central control unit further including first interface means for interfacing said dc power and digital data signals to said two-wire bus; and said cluster controllers each further including second interface means for interfacing said dc power and digital data signals to said two-wire bus, said first interface means and said second interface means each including means responsive to said positive-going transitions and said negative-going transitions in digital data signals received on said bus for reconstructing said digital data signals.

Claim 12

Dependent Claim 182 words

A signalling system comprising: a central control unit including a computer and a dc power source; one or more cluster controllers, each remotely located from said central unit and including a microprocessor; a plurality of sensors associated with and controlled by each cluster controller; a two-wire bus connecting said central unit and said cluster controllers, said bus carrying dc operating power from said power source to said cluster controllers and said plurality of sensors and carrying digital data signals in both directions between said computer and said cluster controllers, said data signals including positive-going transitions and negative-going transitions between binary logic levels; said central control unit further including first interface means for interfacing said dc power and digital data signals to said two-wire bus; and said cluster controllers each further including second interface means for interfacing said dc power and digital data signals to said two-wire bus, said first interface means and said second interface means each including means responsive to said positive-going transitions and said negative-going transitions in digital data signals received on said bus for reconstructing said digital data signals.

Claim 13

Dependent Claim 184 words

A measuring and signalling system comprising: a central control unit including a computer and a dc power source; one or more cluster controllers, each remotely located from said central unit and including a microprocessor; a plurality of sensors associated with and controlled by each cluster controller; a two-wire bus connecting said central unit and said cluster controllers, said bus carrying dc operating power from said power source to said cluster controllers and said plurality of sensors and carrying digital data signals in both directions between said computer and said cluster controllers, said data signals including positive-going transitions and negative-going transitions between binary logic levels; said central control unit further including first interface means for interfacing said dc power and digital data signals to said two-wire bus; and said cluster controllers each further including second interface means for interfacing said dc power and digital data signals to said two-wire bus, said first interface means and said second interface means each including means responsive to said positive-going transitions and said negative-going transitions in digital data signals received on said bus for reconstructing said digital data signals.

Claim 14

Dependent Claim 184 words

A measuring and signalling system comprising: a central control unit including a computer and a dc power source; one or more cluster controllers, each remotely located from said central unit and including a microprocessor; a plurality of sensors associated with and controlled by each cluster controller; a two-wire bus connecting said central unit and said cluster controllers, said bus carrying dc operating power from said power source to said cluster controllers and said plurality of sensors and carrying digital data signals in both directions between said computer and said cluster controllers, said data signals including positive-going transitions and negative-going transitions between binary logic levels; said central control unit further including first interface means for interfacing said dc power and digital data signals to said two-wire bus; and said cluster controllers each further including second interface means for interfacing said dc power and digital data signals to said two-wire bus, said first interface means and said second interface means each including means responsive to said positive-going transitions and said negative-going transitions in digital data signals received on said bus for reconstructing said digital data signals.

Claim 15

Dependent Claim 65 words

A measuring and signalling system as defined in claim 11 wherein said first interface means comprises a transformer having two secondary windings and said power source comprises a voltage source connected in series between said two secondary windings, said two-wire bus being connected across the series combination of said two secondary windings and said voltage source such that said voltage is carried on said bus.

Claim 16

Dependent Claim 59 words

A measuring and signalling system as defined in claim 11 wherein said first interface means comprises a first transformer having secondary windings coupled to said bus, first means for coupling said digital data signals between a primary winding of said first transformer and said computer, and first means for coupling said power source to secondary windings of said transformer.

Claim 17

Dependent Claim 65 words

A measuring and signalling system as defined in claim 13 wherein each of said second interface means comprises a second transformer having secondary windings coupled to said two-wire bus, second means for coupling said digital data signals between a primary winding of said transformer and said microprocessor, and second means for coupling power through said secondary windings of said transformer to the respective cluster controller.

Claim 18

Dependent Claim 73 words

A measuring and signalling system as defined in claim 11 wherein each of said second interface means comprises a transformer having two secondary windings and the respective cluster controller includes a voltage regulator connected in series between said two secondary windings, said two-wire bus being connected across the series combination of said two secondary windings and said voltage regulator such that a voltage carried on said bus is supplied to said voltage regulator.

Claim 19

Dependent Claim 111 words

A measuring and signalling system as defined in claim 14 wherein said first digital data coupling means and said second digital data coupling means each comprise means for differentiating digital data signals received on said bus and providing a voltage pulse of one polarity for each positive going transition in said data signals and a voltage pulse of the opposite polarity for each negative going transition in said data signals, and comparator means for providing a first logic level when said voltage pulse of one polarity crosses a first threshold level and for providing a second logic level when said voltage pulse of the opposite polarity crosses a second threshold level.

Claim 20

Dependent Claim 117 words

A measuring and signalling system as defined in claim 16 wherein said first transformer includes two secondary windings, said power source is connected in series between said two secondary windings and said two-wire bus is connected across the series combination of said two secondary windings and said power source such that said voltage is carried on said bus, and each of said second transformers includes two secondary windings and each of said cluster controllers includes a voltage regulator connected in series between said two secondary windings, said two-wire bus being connected across the series combination of said two secondary windings and said voltage regulator such that power carried on said bus is supplied to said voltage regulator.

Claim 21

Dependent Claim 36 words

A measuring and signalling system as defined in claim 13 further including means for monitoring the current supplied on said two-wire bus and for disconnecting said power source therefrom when the current exceeds a prescribed level.

Claim 22

Dependent Claim 34 words

A measuring and signalling system as defined in claim 18 wherein said monitoring means includes means for sensing the voltage across one of said secondary windings to determine the current supplied on said bus.

Claim 23

Dependent Claim 71 words

An aircraft signalling system as defined in claim 1 wherein said onboard computer further includes means for storing type information and operating parameters for each of said plurality of sensors and for transmitting the type information and the operating parameters to the associated cluster controller when said system is to be put into operation, said type information and operating parameters identifying the type and operating characteristics of each of said sensors.

Claim 24

Dependent Claim 102 words

An aircraft signalling system as defined in claim 1 wherein said onboard computer further includes means for interrogating each of said cluster controllers to obtain an initial signal strength from each of said sensors when said system is initialized, means for storing said initial signal strengths, means for interrogating each of said cluster controllers to obtain a present signal strength from each of said sensors when said system is to be put into operation, and means for indicating a trouble condition when the difference between said present signal strength and said initial signal strength for a sensor is outside a prescribed range.

Claim 25

Dependent Claim 114 words

An aircraft signalling system as defined in claim 1 wherein at least one of said sensors includes a transmitter and a receiver, wherein said transmitter sends a known signal to said receiver and wherein said onboard computer includes means for interrogating the specified cluster controller with which the transmitter and the receiver are associated to obtain a present signal strength from said receiver when said system is to be put into operation, and means for sensing that said present signal strength is outside a prescribed range and for directing the specified cluster controller to vary the energy sent by said transmitter to said receiver until said present signal strength is within said prescribed range.

Claim 26

Dependent Claim 71 words

A measuring and signalling system as defined in claim 11 wherein said computer further includes means for storing type information and operating parameters for each of said plurality of sensors and for transmitting the type information and the operating parameters to the associated cluster controller when said system is to be put into operation, said type information and operating parameters identifying the type and operating characteristics of each of said sensors.

Claim 27

Dependent Claim 102 words

A measuring and signalling system as defined in claim 11 wherein said computer further includes means for interrogating each of said cluster controllers to obtain an initial signal strength from each of said sensors when said system is initialized; means for storing said initial signal strengths; means for interrogating each of said cluster controllers to obtain a present signal strength from each of said sensors when said system is to be put into operation; and means for indicating a trouble condition when the difference between said present signal strength and said initial signal strength for a sensor is outside a prescribed range.

Claim 28

Dependent Claim 114 words

A measuring and signalling system as defined in claim 11 wherein at least one of said sensors includes a transmitter and a receiver, wherein said transmitter sends a known signal to said receiver and wherein said computer includes means for interrogating the specified cluster controller with which the transmitter and the receiver are associated to obtain a present signal strength from said receiver when said system is to be put into operation, and means for sensing that said present signal strength is outside a prescribed range and for directing the specified cluster controller to vary the energy sent by said transmitter to said receiver until said present signal strength is within said prescribed range.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1993-06-11	1993-12-11	1994-06-12	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1997-06-11	1997-12-11	1998-06-12	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2001-06-11	2001-12-11	2002-06-12	$7700.00	Window Closed / Lapsed

Aircraft security system

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