Navigation aid method for making multiple time constraints

Patent metadata

Field	Value
Publication number	US-9945671-B2
Application number	US-201514604308-A
Country	US
Kind code	B2
Filing date	Jan 23, 2015
Priority date	Jan 24, 2014
Publication date	Apr 17, 2018
Grant date	Apr 17, 2018

Abstract

A method assisting in navigation of aircraft following a flight plan subject to time constraints comprises: determining a minimum speed profile, a maximum speed profile, and minimum and maximum times of passage; determining, for each constraint of index i, a restricted interval and a required interval; the determination made by a first iterative computation, i being decremented from n−1 to 1 and comprising: determining a required interval of index i enabling the aircraft to observe a restricted interval of index i+1 by flying at a speed profile between the minimum and maximum speed profiles, the restricted interval of index i+1 determined on the preceding iteration for an iteration of index between 1 and n−2, or from the time constraint of index n for the iteration of index n−1; and determining a restricted interval of index i from the intersection of the time constraint and the required interval of index i.

First claim

The invention claimed is:

1. A method for assisting in a navigation of an aircraft, executed by a mission management system, said aircraft following a flight plan subject to a plurality of time constraints RTA i indexed by an index i varying from 1 to n, the index 1 corresponding to a time constraint closest to a current position (P cour ) of the aircraft and the index n corresponding to a time constraint furthest away from the current position, the position of the aircraft on the flight plan being identified as a function of a curvilinear abscissa X,
a time constraint of index i RTA i being delimited by an earliest time of passage RTA inf i and a latest time of passage RTA sup i and corresponding to a curvilinear abscissa X i ,
the method comprising the steps:
determining a minimum speed profile (V min (X)), a maximum speed profile (V max (X)), and minimum (T Vmin (X)) and maximum (T Vmax (X)) times of passage for an aircraft flying respectively at the minimum (V min (X)) and maximum (V max (X)) speeds, as a function of the curvilinear abscissa X, said minimum and maximum speed profile being determined from at least performances and a state of the aircraft,
determining, for each constraint RTA i of index i a restricted interval RTA R i corresponding to a restricted time constraint interval and a required interval ETA R i corresponding to a required time of passage interval for the aircraft at a waypoint P RTA i of curvilinear abscissa X i ,
said determination being made on a basis of minimum (T Vmin (X)) and maximum (T Vmax (X) time-of-passage profiles and, by a first iterative computation, i being decremented from n−1 to 1 and comprising:
determining a required interval ETA R i of index i enabling the aircraft to observe a restricted interval of index i+1 RTA R i+1 by flying according to a speed profile lying between the minimum (V min ) and maximum (V max ) speed profiles, said restricted interval of index i+1 RTA R i+1 being determined on a preceding iteration for an iteration of index lying between 1 and n−2, or from the time constraint of index n RTA n for the iteration of index n−1,
determining a restricted interval RTA R i of index i from an intersection of the time constraint RTA i and of the required interval ETA R i of index i,
a required interval of index i ETA R i making it possible to observe all the restricted intervals of indices greater than i RTA R i+1 , RTA R i+2 , RTA n by flying according to a speed profile lying between the minimum (V min ) and maximum (V max ) speed profiles, when the constraints of indices greater than i RTA i+1 , RTA i+2 , . . . , RTA n are mutually compatible,
said method further comprising a display step graphically displaying, to a pilot or an operator, information graphically illustrating compatibility of the aircraft to comply with said time constrains RTA i based on the interval RTA R i and the required interval ETA R i .

2. The method according to claim 1 , in which said restricted interval of index i RTA R i is equal to said intersection of the time constraint RTA i and of the required interval ETA R i of index i.

3. The method according to claim 1 , in which said restricted interval of index i RTA R i is equal to said intersection minus a robustness margin.

4. The method according to claim 1 , further comprising, when said intersection is empty during the first iterative computation, the steps:
identifying the corresponding time constraint as incompatible constraint RTA jk and its index as incompatible constraint index (jk),
loading a first chosen time constraint RTA 1 jk determined according to a first criterion or chosen by the pilot and,
resuming said first iterative computation at the incompatible constraint index minus 1 (jk−1) and from a restricted interval RTA R jk corresponding to said loaded first chosen time constraint RTA 1 jk .

5. The method according to claim 4 , in which said first criterion corresponds to choosing, as first chosen time constraint RTA 1 jk , the limit of the time constraint RTA jk of incompatible constraint index (jk) closest to said required interval ETA R jk of incompatible constraint index (jk).

6. The method according to claim 1 , in which the step of determining the required interval ETA R i of index i comprises the substeps:
performing a translation of the curve of maximum time of passage as a function of the curvilinear abscissa X (T Vmax (X)) such that it passes through the upper limit RTA Rsup i+1 of the restricted interval of index i+1 RTA R i+1 of abscissa X i+1 ,
choosing, as upper limit ETA Rsup i of said required interval ETA R i , the value of said curve translated to the curvilinear abscissa X i ,
performing a translation of the curve of minimum time of passage as a function of the curvilinear abscissa X (T Vmin (X)) such that it passes through the lower limit RTA Rinf j+1 of the restricted interval of index i+1 RTA R i+1 of abscissa X i+1 ,
choosing, as lower limit ETA Rinf i of the required interval ETA R i , the value of said curve translated to the curvilinear abscissa X i .

7. The method according to claim 1 , further comprising a step of computation of a required interval ETA R (X cour ), at the current position of the aircraft (X cour ), from the restricted interval of index 1 RTA R 1 .

8. The method according to claim 1 , further comprising the step of determining, for each constraint RTA i of index i, a constrained estimation interval ETAc i corresponding to an estimated interval of constrained time of arrival of the aircraft at the waypoint P RTA i of curvilinear abscissa X i and a possible interval ETAp i corresponding to an interval of the possible estimated times of passage of the aircraft at the waypoint P RTA i of curvilinear abscissa X i ,
said determination being made from minimum (T Vmin (X)) and maximum (T Vmax (X)) time-of-passage profiles and by a second iterative computation, i being incremented from 1 to n, and comprising:
determining a possible interval ETAp i of index i of possible estimated times of passage of the aircraft at the curvilinear abscissa X i by flying according to a speed profile lying between the minimum (V min ) and maximum (V max ) speed profiles and observing a constrained estimation interval ETAc i−1 determined on the preceding iteration for an iteration of index lying between 2 and n, or from the current position of the aircraft (P cour ) for the iteration of index 1,
determining a constrained estimation interval ETAc i of index i from the intersection of the time constraint RTA i and of the possible interval ETAp i of index i,

during the second iterative computation, when said intersection is empty:
identifying the corresponding time constraint as unmakeable constraint RTA lk and its index as unmakeable constraint index lk,
loading a chosen second constraint RTA 2 lk determined according to a second criterion or chosen by the pilot and,
resuming said second iterative computation at the unmakeable constraint index plus 1 (lk+1) and from a constrained estimation interval ETA c lk corresponding to the loaded chosen second constraint RTA 2 lk ,
a possible interval of index i ETAp i making it possible to observe all the constrained estimation intervals of index less than i ETA c i−1 , ETA c i−2 , . . . , ETA c 1 by flying according to a speed profile lying between the minimum (V min ) and maximum (V max ) speed profiles, when all the constraints of indices less than i RTA i−1 , RTA i−2 , . . . , RTA 1 can be made.

9. The method according to claim 8 , in which said second criterion corresponds to choosing, as second chosen time constraint RTA

Assignees

• Thales Sa

Inventors

• Dacre-Wright Benoit
• Deker Guy
• Blanchon Xavier

Classifications

• G05D1/101

  specially adapted for aircraft · CPC title

• G01C21/00 Primary

  Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 (measuring distance traversed on the ground by a vehicle G01C22/00; control of position, course, altitude or attitude of vehicles G05D1/00; traffic control systems for road vehicles involving transmission of navigation instructions to the vehicle G08G1/0968) · CPC title

• G08G5/32 Primary

  for flight plan preparation · CPC title