Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Aeronautical vehicle
Patent
1999-04-09
2000-05-09
Cuchlinski, Jr., William A.
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Aeronautical vehicle
701 14, 701121, 701204, 340949, 340968, 73178R, 244 11, G06F 700
Patent
active
060616121
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for managing air speed with a view to complying with the time constraints of an aerodyne in an unsettled meteorological environment.
2. Discussion of the Background
In general, it is known that the current trend is for the flight management systems of aerodynes to be ever more intimately incorporated into the air traffic management mechanisms, by involving digital ground/on-board communication means, more accurate locating means and more powerful computing means on the ground. Furthermore, these aerodynes carry on-board equipment which makes it possible to take into account ever more reliable and accurate meteorological forecasts. It therefore becomes possible to improve compliance with time constraints and therefore to reduce the admissible time windows associated with these constraints.
Furthermore, the strategy for the time constraints is different for each of the partners of the air transport.
Customarily, the pilot desires to manage these constraints as flexibly as possible (perhaps avoiding them) while taking into account the inaccuracy in the weather forecasts. In fact, he wants to avoid large variations in aircraft speed and engine revs for reasons of aircraft performance and engine lifetime.
For his part, the air traffic controller desires that the time constraints be managed as far upstream as possible of the flights so as to benefit from extra distance in order to cope with the time constraint by reducing (or increasing) the aircraft speed whilst leaving the aircraft on its path. In fact, the air traffic controller prefers to give instructions regarding time of transit as early as possible during the cruising segment. Thus, the traffic flows as forecast without creating additional conflicts.
It turns out that in spite of the abovementioned means, possible causes of error remain, especially in the realm of meteorological forecasts, which may lead to non-compliance with the time constraints.
SUMMARY OF THE INVENTION
The purpose of the invention is therefore a management process which makes it possible, through a straightforward mechanism, to counterbalance these (residual) errors in such a way as to guarantee compliance with the time constraints whilst nevertheless remaining consistent with the aspirations of pilots and air traffic controllers.
According to the invention, this process comprises at least two successive phases, namely: onwards of which, theoretically, it becomes materially impossible to keep to the time constraint requested by following the previously scheduled speed profile, and where it becomes necessary to alter this speed profile over the portion of path remaining to be performed, and the determination of a new speed profile over the portion of path remaining to be performed with a view to complying with the constraint, this portion of path comprising segments and this new profile being obtained by determining segment-by-segment speed corrections starting from the aforementioned point and up to the last modifiable segment, the speed variation in each of the segments being limited to a maximum value so as to avoid overly large variations in speed with respect to the optimal speed, given segment starts from the curve giving the time of flight t as a function of the speed V, this curve being represented by an approximate curve satisfying an equation with three coefficients c.sub.1, c.sub.2 and C.sub.3 : determine three times of flight and define three points of support of the curve, the computation of the new speed comprising the following steps: that the approximate curve passes through the three points of support Vapp.sub.1 of the speed so as to satisfy the constrained time of flight tcstr for the approximate value of the speed, flight determined is sufficiently close to the constrained time tcstr, support closest to the constrained time (from among the time of flight values which were previously supplied by the path computations) for as long as the time of flight determined is to
REFERENCES:
patent: 5445021 (1995-08-01), Cattoen et al.
patent: 5457634 (1995-10-01), Chakravarty
patent: 5508928 (1996-04-01), Tran
Perennec Myriam
Sainthuile Gerard
Beaulieu Yonel
Cuchlinski Jr. William A.
Sextant Avionique
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