US3778602A — Area navigation computer and solid state filter

Claim 1

Independent Claim 147 words

In an avionics system of the type that receives and utilizes a bearing signal for navigation purposes, said bearing signal including the VOR reference signal and a VOR variable signal, means for receiving said VOR reference signal and VOR variable signal, said receiving means having signal outputs therefrom corresponding to the received VOR reference signal and a received VOR variable signal, the improvement comprising means for utilizing said received VOR reference and VOR variable signals to produce an altered VOR variable signal substantially free of multipath, course scallop and other signal errors adversely affecting aircraft navigation using said bearing signal, said altered signal producing means further having a time constant lag produced therein, and said altered signal producing means including a means for compensating for said time constant lag and operable to improve the accuracy of said avionics system utilizing said bearing VOR signals for navigation purposes.

Claim 2

Dependent Claim 147 words

In an avionics system of the type that receives and utilizes a bearing signal for navigation purposes, said bearing signal including the VOR reference signal and a VOR variable signal, means for receiving said VOR reference signal and VOR variable signal, said receiving means having signal outputs therefrom corresponding to the received VOR reference signal and a received VOR variable signal, the improvement comprising means for utilizing said received VOR reference and VOR variable signals to produce an altered VOR variable signal substantially free of multipath, course scallop and other signal errors adversely affecting aircraft navigation using said bearing signal, said altered signal producing means further having a time constant lag produced therein, and said altered signal producing means including a means for compensating for said time constant lag and operable to improve the accuracy of said avionics system utilizing said bearing VOR signals for navigation purposes.

Claim 3

Dependent Claim 75 words

A combination as in claim 1 wherein said altered signal producing means includes a means for sensing the rate at which said bearing signal is changed, said compensating means being operable to produce a compensating signal corresponding to said sensed bearing signal changing rate, said compensating signal being utilized with said altered signal producing means and operable to adjust said output of said altered signal producing means thereby eliminating said lag in said altered signal.

Claim 4

Dependent Claim 92 words

The combination as in claim 2 wherein said altered signal producing means includes a phase detector, means for applying said received variable VOR signal to said phase detector, means for combining said variable VOR signal to produce said altered VOR variable signal, and means for applying said altered VOR variable signal to said phase detector, said phase detector thereby having an output signal corresponding to the error in phase between said received VOR variable signal and the altered VOR signal, said altered signal being generally insensitive to VOR course scalloping error effects.

Claim 5

Dependent Claim 139 words

In an area navigation computer of the type that receives and develops a VOR bearing signal, said developed VOR bearing signal having a reference signal component and a variable signal component which are utilizable for navigation purposes, the improvement comprising a means for producing an altered bearing signal, said signal producing means operable to reject errors in said variable component of said received bearing signal such as VOR course scalloping, said signal producing means including a means for sensing the rate at which the variable component of the received VOR bearing signal is changing, and means for producing a compensating signal corresponding to said changing rate, said compensating signal being utilized with said altered signal producing means and operable to adjust said altered signal thereby eliminating the potential lag inducible by the use of said altered signal producing means.

Claim 6

Dependent Claim 139 words

In an area navigation computer of the type that receives and develops a VOR bearing signal, said developed VOR bearing signal having a reference signal component and a variable signal component which are utilizable for navigation purposes, the improvement comprising a means for producing an altered bearing signal, said signal producing means operable to reject errors in said variable component of said received bearing signal such as VOR course scalloping, said signal producing means including a means for sensing the rate at which the variable component of the received VOR bearing signal is changing, and means for producing a compensating signal corresponding to said changing rate, said compensating signal being utilized with said altered signal producing means and operable to adjust said altered signal thereby eliminating the potential lag inducible by the use of said altered signal producing means.

Claim 7

Dependent Claim 106 words

The combination as in claim 4 wherein said altered signal producing means includes a phase detector, means for applying said received VOR variable signal component to said phase detector, means for combining said received variable VOR signal component with said reference signal component to produce said altered VOR variable signal, and means for applying said altered VOR variable signal component to said phase detector, said phase detector thereby having an output signal corresponding to the error between the received variable VOR signal component and the altered variable VOR signal component, said altered signal being generally insensitive to VOR course scalloping and other navigational error signal effects.

Claim 8

Dependent Claim 116 words

The combination as in claim 5 wherein said combining means includes a first integrator means for integrating the error signal output of said phase detector, a filter means for filtering said error signal and having an output representing detected phase error, the outputs of said first integrator means and said last mentioned filter means being summed to produce a signal representative of the rate of change of the phase of the received variable VOR signal component, a second integrator means for integrating said rate of change signal to produce a signal representing the desired phase of the variable signal, said signal representative of said desired phase being utilizable to produce said altered VOR variable signal component.

Claim 9

Dependent Claim 60 words

The combination as in claim 6 including a phase shifter, means for applying a reference signal to said phase shifter, said reference signal being the VOR reference signal component, and means for applying said output signal from said second integrator representative of said desired phase to said phase shifter, said phase shifter thereby producing the altered variable VOR signal component.

Claim 10

Dependent Claim 122 words

An altered bearing signal producing means for avionics equipment, said signal producing means having an input and an output and comprising a phase detector, means for applying a received variable signal to said phase detector, means for applying the output of said altered signal producing means to said phase detector, said phase detector thereby having an output signal corresponding to a preselected difference between the received variable signal and the output of said altered signal producing means, and means for integrating the output of the phase detector to present undesirable signal conditions therein, including noise, said integrating means having an output operable to assist in the elimination of said undesirable signal conditions in said output of said altered bearing signal producing means.

Claim 11

Dependent Claim 122 words

An altered bearing signal producing means for avionics equipment, said signal producing means having an input and an output and comprising a phase detector, means for applying a received variable signal to said phase detector, means for applying the output of said altered signal producing means to said phase detector, said phase detector thereby having an output signal corresponding to a preselected difference between the received variable signal and the output of said altered signal producing means, and means for integrating the output of the phase detector to present undesirable signal conditions therein, including noise, said integrating means having an output operable to assist in the elimination of said undesirable signal conditions in said output of said altered bearing signal producing means.

Claim 12

Dependent Claim 21 words

The combination as in claim 8 including means for preventing unstable conditions at the output of said altered signal producing means.

Claim 13

Dependent Claim 27 words

The combination as in claim 9 wherein said preventing means includes means for adding a variable delay signal within a portion of said altered signal producing means.

Claim 14

Dependent Claim 68 words

The combination as in claim 8 wherein said altered signal producing means includes a means for generating a periodic recurring signal, means for comparing the output of said integrating means with the recurring signal, and means for correlating the phase of the output of said integrator means with the phase of the recurring signal when said integrating means output reaches a preselected value relative to said recurring signal.

Claim 15

Dependent Claim 50 words

The combination as in claim 11 wherein said correlating means includes a detection means for initiating slewing of the output from said integrator means to the corresponding value of said periodic recurring signal when the output of said integrating means exceeds the maximum output of said recurring signal generating means.

Claim 16

Dependent Claim 52 words

The combination as in claim 11 wherein said correlating means includes a detection means for initiating slewing of the output from said integrator means to the corresponding valve of said periodic recurring signal when the output of said integrating means is less than the minimum output of said recurring signal generating means.

Claim 17

Dependent Claim 40 words

The combination as in claim 8 including means for detecting the amount of phase error in the output of said phase detector, and means for increasing the response time of said filter when said phase error exceeds a predetermined amount.

Claim 18

Dependent Claim 142 words

In an avionics system of the type that receives and utilizes a bearing signal for area navigation purposes, the said bearing signal including a reference VOR signal component and a variable VOR signal component, the improvement comprising, a phase detector, means for applying the variable VOR signal component to said phase detector, said phase detector having an oUtput emanating therefrom, means for filtering the output of said phase detector, a phase shifter, the output of said filter means being interconnected with said phase shifter, said phase shifter operable to shift the phase of said reference signal, and means interconnecting the output of said phase shifter with said phase detector and to thereby form a phase lock loop, said output of said phase shifter being utilized as substantially noiseless and navigational error free bearing signal for navigation purposes by said area navigation system.

Claim 19

Dependent Claim 142 words

In an avionics system of the type that receives and utilizes a bearing signal for area navigation purposes, the said bearing signal including a reference VOR signal component and a variable VOR signal component, the improvement comprising, a phase detector, means for applying the variable VOR signal component to said phase detector, said phase detector having an oUtput emanating therefrom, means for filtering the output of said phase detector, a phase shifter, the output of said filter means being interconnected with said phase shifter, said phase shifter operable to shift the phase of said reference signal, and means interconnecting the output of said phase shifter with said phase detector and to thereby form a phase lock loop, said output of said phase shifter being utilized as substantially noiseless and navigational error free bearing signal for navigation purposes by said area navigation system.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1976-12-10	1977-06-11	1977-12-11	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1980-12-10	1981-06-11	1981-12-11	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1984-12-10	1985-06-11	1985-12-11	$7700.00	Window Closed / Lapsed

Area navigation computer and solid state filter

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