Airplane position assurance monitor

• US 8,630,756 B2
• Filed: 04/12/2011
• Issued: 01/14/2014
• Est. Priority Date: 04/12/2011
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Fleiger-Holmes, Steven L., Murphy, Timothy Allen, Crane, Jean Marie
• Primary Examiner(s): Trammell, James
• Assistant Examiner(s): Do, Truc M
• Application Number:
  US13/085,310
• Publication Number:
  US 20120265376A1
• Time in Patent Office: 1,008 Days
• Field of Search: 701/14, 701/15, 701/16, 701/17, 701/120, 701/528
• US Class Current: 701/16
• CPC Class Codes: B64D 43/00 Arrangements or adaptations of instruments arrangements of cameras B64D47/08; aeronautical measuring instruments per se G01C
• CPC Class Codes: B64D 45/04 Landing aids; Safety measures to prevent collision with earth's surface
• CPC Class Codes: G01C 5/005 altimeters for aircraft G01C5/02, G01C5/06 take precedence
• CPC Class Codes: G01S 1/18 Elevational guidance systems, e.g. system for defining aircraft glide path
• CPC Class Codes: G01S 19/15 Aircraft landing systems
• CPC Class Codes: G01S 19/20 Integrity monitoring, fault detection or fault isolation of space segment
• CPC Class Codes: G05D 1/0676 specially adapted for landing
• CPC Class Codes: G08G 5/0021 located in the aircraft
• CPC Class Codes: G08G 5/0026 located on the ground
• CPC Class Codes: G08G 5/02 Automatic approach or landing aids, i.e. systems in which flight data of incoming planes are processed to provide landing data landing aids fitted in or to aircraft B64D45/04; visual or acoustic landing aids B64F1/18
• CPC Class Codes: G08G 5/025 Navigation or guidance aids radar or analogous systems specially adapted for landing purposes G01S13/913

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.

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.

2. The method as recited in claim 1, wherein the airplane location is a location of a control guidance point.

3. The method as recited in claim 1, further comprising determining the coordinates of the airplane location using GPS signals.

4. The method as recited in claim 1, further comprising retrieving the coordinates of the location of the ground-based antenna from a database.

5. The method as recited in claim 1, further comprising:

retrieving the runway heading from a database; and

determining the coordinates of a location along the extended runway centerline which is closest to the airplane location.

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.

7. The system as recited in claim 6, further comprising a device that produces an audible or visible warning in response to generation of said alert signal.

8. The system as recited in claim 6, further comprising a GPS receiver for receiving GPS signals, wherein said computer system is further programmed to derive the coordinates of the airplane location from the GPS signals received by said GPS receiver.

9. The system as recited in claim 6, further comprising a navigation database, wherein said computer system is further programmed to retrieve the coordinates of the location of the localizer transmitter from said navigation database.

10. The system as recited in claim 6, further comprising a navigation database, wherein said computer system is further programmed to perform the following operations:

retrieving the runway heading from said navigation database; and

determining the coordinates of a location along the extended runway centerline which is closest to the airplane location.

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.