Time available before aircraft auto-recovery begins

Patent metadata

Field	Value
Publication number	US-11273928-B2
Application number	US-201916552612-A
Country	US
Kind code	B2
Filing date	Aug 27, 2019
Priority date	Aug 27, 2018
Publication date	Mar 15, 2022
Grant date	Mar 15, 2022

Abstract

An avionics system for an aircraft includes a threat data structure and a processor. The threat data structure stores an alert threshold and a margin threshold. The processor is programmed to: predict an aircraft state at a plurality of positions along a potential future trajectory; calculate a margin value at each of the plurality of positions as a difference between the predicted future condition and the threat value at each respective one of the plurality of positions; calculate a margin rate of change at each of the plurality of positions based on a change in the margin value along the potential future trajectory; estimate a time to go value based on a minimum calculated margin value and a maximum calculated margin rate of change among the plurality of positions; and command an indicator to alert the pilot in response to the time to go value reaching the alert threshold.

First claim

What is claimed is:

1. An avionics system for an aircraft, comprising:
a memory circuit including a threat data structure storing an alert threshold and a margin threshold below which the avionics system will engage an autopilot recovery of the aircraft, the margin threshold indicating a difference limit between a predicted future condition and a threat value, and the alert threshold indicating a predetermined amount of time the avionics system would preferably alert a pilot before engaging an autopilot; and
a processor coupled to the memory circuit, the processor programmed to:
predict an aircraft state at each of a plurality of positions along a potential future trajectory available to the aircraft;
calculate a margin value (MGN) at each of the plurality of positions as a difference between the predicted future condition and the threat value at each respective one of the plurality of positions;
calculate a margin rate of change (MGNdot) along the potential future trajectory;
estimate a time to go (TTG) value based on a minimum calculated margin value (MGN MIN ) and a maximum calculated margin rate of change (MGNdot MAX ) among the plurality of positions; and
command an indicator to alert the pilot in response to the time to go value reaching the alert threshold.

2. The avionics system of claim 1 , wherein the processor is programmed to calculate MGNdot based on at least one of:
a change in the margin value along the potential future trajectory at each of the plurality of positions;

a rate of change of a current value of the condition at the start of the prediction;
a rate of change of the condition at the start of the prediction less the rate of change of the limit at each of the plurality of positions.

3. The avionics system of claim 1 , wherein the processor is further programmed to set TTG to a negative value equal to a proportion of MGN MIN in response to determining that a predicted limit violation has occurred.

4. The avionics system of claim 3 , wherein the processor is further programmed to set TTG as out of range in response to MGNdot MAX being less than or equal to zero.

5. The avionics system of claim 1 , wherein the processor is further programmed to calculate TTG according to:

MGN
MIN

(

MGNdot
MAX

)

=

TTG
.

6. The avionics system of claim 5 , wherein the processor is further programmed to calculate MĠN and MĠN MAX for each of a plurality of potential future trajectories independent of each other of the plurality of potential future trajectories.

7. The avionics system of claim 1 , wherein the processor is further programmed to calculate MGNdot at each of the plurality of positions according to:

MGNdot
=

MGN
i

-

MGN

i
-
1

t
i

-

t

i
-
1

,

where i is a current position of the plurality of positions and t is a time variable projected ahead of the aircraft along the potential future trajectory.

8. An aircraft, comprising:
a memory circuit including a threat data structure storing an alert threshold and a margin threshold below which the avionics system will engage an autopilot recovery of the aircraft, the margin threshold indicating a difference limit between a predicted future condition and a threat value, and the alert threshold indicating a predetermined amount of time the aircraft would preferably alert a pilot before engaging an autopilot; and
a processor coupled to the memory circuit, the processor programmed to:
predict an aircraft state at each of a plurality of positions along a potential future trajectory available to the aircraft;
calculate a margin value (MGN) at each of the plurality of positions as a difference between the predicted future condition and the threat value at each respective one of the plurality of positions;
calculate a margin rate of change (MGNdot) along the potential future trajectory;
estimate a time to go (TTG) value based on a minimum calculated margin value (MGN MIN ) and a maximum calculated margin rate of change (MGNdot MAX ) among the plurality of positions; and
command an indicator to alert the pilot in response to the time to go value reaching the alert threshold.

9. The aircraft of claim 8 , wherein the processor is further programmed to engage the autopilot without regard to the time to go value and the alert threshold.

10. The aircraft of claim 8 , wherein the processor is further programmed to set TTG to a negative value equal to a proportion of MGN MIN in response to determining that a predicted limit violation has occurred.

11. The aircraft of claim 8 , wherein the processor is further programmed to set TTG as out of range in response to MGNdot MAX being less than or equal to zero.

12. The aircraft of claim 8 , wherein the processor is further programmed to calculate TTG according to:

MGN
MIN

(

MGNdot
MAX

)

=

TTG
.

13. The aircraft of claim 8 , wherein the processor is further programmed to calculate MĠN and MĠN MAX for each of a plurality of potential future trajectories independent of each other of the plurality of potential future trajectories.

14. The aircraft of claim 8 , wherein the processor is further programmed to calculate MĠN at each of the plurality of positions according to:

MGNdot
=

MGN
i

-

MGN

i
-
1

t
i

-

t

Assignees

• Gulfstream Aerospace Corp

Inventors

• Prosser Kevin
• Finlayson Blake
• Vaidya Abhishek
• Sakhaei Alborz

Classifications

• G08G5/55

  for a single aircraft · CPC title

• G08G5/53

  for cruising · CPC title

• G08G5/23

  Details of user output interfaces, e.g. information presented · CPC title

• G08G5/21 Primary

  located onboard the aircraft · CPC title

• G08G5/723

  from the aircraft · CPC title