Airplane position assurance monitor
First Claim
1. A method for monitoring positional accuracy of an airplane approaching a runway, comprising the following steps performed by a computer system during the approach:
- (a) determining a first ground distance between a location of the airplane and a location along an extended runway centerline that is closest to the airplane location based on respective coordinates of the locations;
(b) determining a second ground distance between the airplane location and a location of a ground-based antenna based on respective coordinates of the airplane and ground-based antenna locations;
(c) determining a first lateral angular deviation of the airplane from the runway centerline based on the first and second ground distances;
(d) receiving a second lateral angular deviation of the airplane from the runway centerline based on measurements of a difference in the depth of modulation of first and second modulated signals transmitted from the ground-based antenna and received by an antenna onboard the airplane;
(e) comparing the first and second lateral angular deviations; and
(f) generating an alert signal if the first and second lateral angular deviations differ by an amount greater than a threshold value.
2 Assignments
0 Petitions
Accused Products
Abstract
An onboard monitor that ensures the accuracy of data representing the calculated position of an airplane during final approach to a runway. This airplane position assurance monitor is a software function that uses dissimilar sources of airplane position and runway data to ensure the accuracy of the respective data from those dissimilar sources. ILS data and GPS or GPS/Baro data are the dissimilar sources of airplane position data used by this function. This function will calculate the airplane'"'"'s angular deviations from the runway centerline and from the glide slope with onboard equipment and then compares those angular deviations to the ILS angular deviation information.
-
Citations
11 Claims
-
1. A method for monitoring positional accuracy of an airplane approaching a runway, comprising the following steps performed by a computer system during the approach:
-
(a) determining a first ground distance between a location of the airplane and a location along an extended runway centerline that is closest to the airplane location based on respective coordinates of the locations; (b) determining a second ground distance between the airplane location and a location of a ground-based antenna based on respective coordinates of the airplane and ground-based antenna locations; (c) determining a first lateral angular deviation of the airplane from the runway centerline based on the first and second ground distances; (d) receiving a second lateral angular deviation of the airplane from the runway centerline based on measurements of a difference in the depth of modulation of first and second modulated signals transmitted from the ground-based antenna and received by an antenna onboard the airplane; (e) comparing the first and second lateral angular deviations; and (f) generating an alert signal if the first and second lateral angular deviations differ by an amount greater than a threshold value. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A system for monitoring positional accuracy of an airplane approaching a runway, comprising:
-
a localizer receiver for determining a first lateral angular deviation of the airplane from the runway centerline based on measurements of a difference in the depth of modulation of first and second modulated signals transmitted from a ground-based localizer transmitter; and a computer system that is programmed to perform the following operations during the approach; (a) determining a first ground distance between a location of the airplane and a location along an extended runway centerline that is closest to the airplane location based on respective coordinates of the locations; (b) determining a second ground distance between the airplane location and a location of the ground-based localizer transmitter based on respective coordinates of the airplane and localizer transmitter locations; (c) determining a second lateral angular deviation of the airplane from the runway centerline based on the first and second ground distances; (d) comparing the first and second lateral angular deviations; and (e) generating an alert signal if the first and second lateral angular deviations differ by an amount greater than a threshold value. - View Dependent Claims (7, 8, 9, 10)
-
-
11. A method for monitoring positional accuracy of an airplane approaching a runway, comprising the following steps performed by a computer system during the approach:
-
(a) calculating a first ground distance between a location of the airplane and a closest location along an extended runway centerline that is closest to the airplane location using respective coordinates of the airplane location and the closest location along the extended runway line and not using lateral angular deviation; (b) calculating a second ground distance between the airplane location and a location of a ground-based antenna using respective coordinates of the airplane and ground-based antenna locations and not using lateral angular deviation; (c) calculating a first lateral angular deviation of the airplane from the runway centerline equal to an angle whose sine equals the ratio of first ground distance to the second ground distance; (d) calculating a second lateral angular deviation of the airplane from the runway centerline based on measurements of a difference in the depth of modulation of first and second modulated signals transmitted from the ground-based antenna and received by an antenna onboard the airplane; (e) comparing the first and second lateral angular deviations; and (f) generating an alert signal if the first and second lateral angular deviations differ by an amount greater than a threshold value.
-
Specification