Consistent localizer captures

An avionics system of an aircraft for guiding the aircraft during a final approach towards a runway, the avionics system comprising:

• an instrument landing system sensor configured to receive guidance signals from a localizer transmitter during the final approach of the aircraft towards the runway;
• a navigation system comprising
• a location component configured to acquire a geographic position of the aircraft,
• a navigation database configured to store a geographic position of a runway threshold of the runway, a geographic position of a runway threshold of the runway, and
• a runway azimuth of the runway, and
• a flight management function configured to
• receive the geographic position of the aircraft, the geographic position of a runway threshold of the runway, and the runway azimuth of the runway from the navigation database,
• compute a distance from the geographic position of the aircraft to the geographic position of the runway threshold,
• compute a bearing to the geographic position of the runway threshold utilizing the geographic position of the aircraft and the geographic position of the runway threshold,
• project the distance from the geographic position of the aircraft to the geographic position of the runway threshold into an along runway component and a cross runway component utilizing the runway azimuth of the runway,
• determine a distance from the geographic position of the runway threshold to a geographic position of a localizer transmitter,
• compute a distance geographically along the runway from the geographic position of the aircraft to the geographic position of the localizer transmitter utilizing the distance from the geographic position of the runway threshold to the geographic position of the localizer transmitter, and
• provide the distance from the geographic position of the aircraft to the geographic position of the localizer transmitter to a deviation calculator;
• and
• the deviation calculator being configured to
• convert an angular localizer deviation into a rectilinear localizer deviation utilizing, in part, the distance along the runway from the geographic position of the aircraft to the geographic position of the localizer transmitter, and
• provide the rectilinear localizer deviation to a guidance system for guiding the aircraft during the final approach towards the runway.

A physical computer storage device having computer readable instructions that, when executed by a computer of an aircraft, cause the computer to:

• receive a geographic position of the aircraft;
• receive a geographic position of a runway threshold of a runway;
• receiving a runway length of the runway;
• receive a runway azimuth of the runway;
• compute a distance from the aircraft to the runway threshold utilizing the geographic position of the aircraft and the geographic position of the runway threshold;
• compute a bearing to the geographic position of the runway threshold utilizing the geographic position of the aircraft and the geographic position of the runway threshold;
• project the distance from the geographic position of the aircraft to the geographic position of the runway threshold into an along runway component and a cross runway component utilizing the runway azimuth of the runway;
• compute a distance geographically along the runway from the geographic position of the aircraft to a geographic position of a localizer transmitter by adding the runway length to the along runway component of the projection of the distance from the geographic position of the aircraft to the geographic position of the runway threshold;
• convert an angular localizer deviation into a rectilinear localizer deviation utilizing, in part, the distance along the runway from the geographic position of the aircraft to the geographic position of the localizer transmitter;
• and
• output the rectilinear localizer deviation to a guidance system for guiding the aircraft during a final approach towards the runway.