System and method for simplified aircraft brake distance estimation
View Patent ↗A braking system and method utilizing a simplified estimate of a distance between two locations on the earth based on spherical geometry. A braking system utilizing the aforementioned simplified estimate does not require computationally intensive calculations and is more efficient and better equipped to handle real-time generation of distance estimates for braking needs and variable conditions. In the present invention, geodesics evaluations are not used; rather, a modified Haversine formula that simplifies computations is used, including a one-time computation of the cosine of latitude coordinate.
1. A braking system for reducing a speed of an aircraft on a runway, comprising:
a processor including a memory for storing a program to calculate braking parameters;
a braking actuator responsive to commands from the processor; and
an aircraft navigation system adapted to provide current aircraft position data and position data for a selected location on said runway to the processor;
wherein the processor uses a Haversine formula small angle simplification to estimate the distance between a current aircraft position and the selected location on said runway; and
wherein the processor commands the braking actuator to reduce the speed of the aircraft based on the estimate of the distance between the current aircraft position and the selected location on said runway.
2. The braking system for reducing a speed of an aircraft of claim 1 , wherein the braking system uses a preselected exit position to determine the braking actuator's reduction of the aircraft speed to minimize a residency time on a runway.
3. The braking system of claim 1 , wherein the estimate of the distance between the current aircraft position and the selected location on said runway computes the cosine of the latitude angle using a truncated power series.
4. The braking system of claim 1 , wherein the estimate of the distance between the current aircraft position and the selected location on said runway computes the cosine of the latitude angle using a lookup table.
5. A method for adjusting instantaneous deceleration of an aircraft to minimize an occupancy of an aircraft on a runway, comprising:
obtaining a current aircraft position after touchdown using geodetic data;
generating a deceleration profile for the aircraft to travel from touchdown to a selected location on said runway with a selected exit taxi speed;
determining a distance from a current aircraft location to a selected location on said runway from the geodetic data using a Haversine formula small angle derivation for a distance estimation;
generating a deceleration profile using the distance estimation and current aircraft speed and current aircraft position; and
commanding a brake actuator to decelerate the aircraft based on the generated deceleration profile.
6. The method of claim 5 , wherein the estimation of the distance between the current aircraft position and the selected location on said runway computes the cosine of a latitude angle using a truncated power series.
7. The method of claim 5 , wherein the estimation of the distance between the current aircraft position and the selected location on said runway computes the cosine of a latitude angle using a lookup table.
8. A braking system for reducing a speed of an aircraft on a runway, comprising:
a processor including a memory for storing a program to calculate braking parameters;
a braking actuator responsive to commands from the processor; and
an aircraft navigation system adapted to provide current aircraft position data and position data for a selected location on said runway to the processor;
wherein the processor uses a Haversine formula small angle simplification to estimate the distance between a current aircraft position and the selected location on said runway; and
wherein the processor generates a deceleration profile and issues a warning signal if there is potential for the aircraft to overrun the selected location based on the deceleration profile.
9. The braking system of claim 8 , wherein the deceleration profile and warning signal are generated prior to and after aircraft touchdown on the runway.
10. The braking system of claim 8 , wherein the estimation of the distance between the current aircraft position and the selected position on the runway computes the cosine of the latitude angle using a truncated power series.
11. The braking system of claim 8 , wherein the estimation of the distance between the current aircraft position and the selected position on the runway computes the cosine of the latitude angle using a lookup table.
12. A method for adjusting instantaneous deceleration of an aircraft to minimize an occupancy of an aircraft on a runway, comprising:
obtaining a current aircraft position after touchdown using geodetic data;
generating a deceleration profile for the aircraft to travel from touchdown to a selected location on said runway with a selected exit taxi speed;
determining a distance from a current aircraft location to a selected location on said runway from the geodetic data using a Haversine formula small angle derivation for a distance estimation;
generating a deceleration profile using the distance estimation and current aircraft speed and current aircraft position; and
generating a deceleration profile and issuing a warning signal to a cockpit of the aircraft if there is potential for the aircraft to overrun the selected location on the runway.
13. The method of claim 12 , wherein the deceleration profile and warning signal are generated prior to and after aircraft touchdown on the runway.
14. The method of claim 12 , wherein the estimation of the distance between the current aircraft position and the selected location on the runway computes the cosine of the latitude angle using a truncated power series.
15. The method of claim 12 , wherein the estimation of the distance between the current aircraft position and the selected location on the runway computes the cosine of the latitude angle using a lookup table.
16. A braking system for reducing a speed of an aircraft, comprising:
a processor including a memory for storing a program to calculate braking parameters;
a braking actuator responsive to commands from the processor; and
an aircraft navigation system adapted to provide current aircraft position data and position data for a selected location on said runway to the processor;
wherein the processor uses a Haversine formula small angle simplification to estimate the distance between a current aircraft position and the selected location on said runway; and
wherein the processor commands the braking actuator to initiate maximum braking force when the processor determines that the aircraft will overrun the selected location on said runway.
17. The braking system of claim 16 , wherein the estimation of the distance between the current aircraft position and the selected location on said runway computes the cosine of the latitude angle using a truncated power series.
18. The braking system of claim 16 , wherein the estimation of the distance between the current aircraft position and the selected location on said runway computes the cosine of the latitude angle using a lookup table.
19. The braking system of claim 16 , further including the step of generating a warning signal when the processor determines that the aircraft will overrun the selected location on said runway.
20. A method for reducing a speed of an aircraft, comprising:
providing a processor including memory for storing a program for calculating braking parameters;
providing a braking actuator responsive to commands from the processor;
incorporating an aircraft navigation system that provides current aircraft position data and position data for a selected location on a runway to the processor;
using a Haversine formula small angle simplification to estimate a distance between the current aircraft position and the selected location on the runway; and
commanding the braking actuator to initiate maximum a braking force when the processor determines that the aircraft will overrun the selected location on the runway.
21. The method of claim 20 , wherein the estimation of the distance between the current aircraft position and the selected location on the runway is computed using a truncated power series for the cosine of the latitude angle.
22. The method of claim 20 , wherein the estimation of the distance between the current aircraft position and the selected location on the runway is computed using a look-up table for the cosine of the latitude angle.
23. The method of claim 20 , further including a step of generating a warning signal when the processor determines that the aircraft will overrun the selected location on the runway.