Air traffic control system

• US 6,420,993 B1
• Filed: 06/26/2000
• Issued: 07/16/2002
• Est. Priority Date: 08/24/1999
• Status: Expired due to Fees

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Varon, Dan
• Primary Examiner(s): Sotomayor, John B.
• Application Number:
  US09/603,752
• Time in Patent Office: 750 Days
• Field of Search: 342/29, 342/30, 342/31, 342/32, 342/36, 342/37, 342/38, 342/40, 342/41
• US Class Current: 342/36
• CPC Class Codes: G08G 5/0078 for monitoring traffic from the aircraft radar or analogous systems specially adapted for traffic control G01S13/91

Abstract

An apparatus and techniques for predicting conflicts between maneuvering aircraft which does not provide an excessive number of false alarms. The techniques utilize information to limit the time interval during which conflict predictions are made such that the predictions are made when they are most likely to be true.

Claims

1. A method for predicting conflicts between at least two objects one of which is maneuvering relative to the other, the method comprising the steps of:

(a) determining if there is an interval overlap between the at least two objects;

(b) determining if a separation criteria between the at least two objects is satisfied; and

(c) determining if the at least two objects are converging.

2. The method of claim 1 wherein the step of determining if the at least two objects are converging comprises the steps of:

interpolating the positions and altitudes of the at least two objects;

computing horizontal and vertical distances;

computing convergence factors for the at least two objects;

computing relative speeds of the at least two objects;

computing a violation interval of at least two objects; and

performing an interval overlap check.

3. The method of claim 2 wherein the step of interpolating the positions and altitudes of the at least two objects comprises the steps of:

retrieving the positions, altitudes and time of the current and previous scans of the at least two objects;

computing the increments in the targets system-plane-positions and altitudes; and

synchronizing the targets positions and altitudes.

4. The method of claim 2 wherein the step of computing the horizontal and vertical distances comprises the steps of:

computing the horizontal distance as R_h,n=[(Δ

X_12,n)²+(Δ

Y_12,n)²]^½

; and

computing the vertical distance as R_v,n=|Δ

Z_12,n|.

5. The method of claim 2 wherein the step of computing the relative speeds of the at least two objects comprises the steps of:

computing an approach speed;

computing a head-on speed; and

computing a vertical speed.

6. The method of claim 2 wherein the step of computing the violation interval of at least two objects comprises the steps of:

computing a violation start time; and

computing a violation end time.

7. An apparatus for predicting conflicts between at least two objects one of which is maneuvering relative to the other, the apparatus comprising:

(a) means for determining if there is an interval overlap between the at least two objects;

(b) means for determining if a separation criteria between the at least two objects is satisfied; and

(c) means for determining if the at least two objects are converging.

8. The apparatus of claim 7 wherein said means for determining if the at least two objects are converging comprises:

means for interpolating the positions and altitudes of the at least two objects;

means for computing horizontal and vertical distances;

means for computing convergence factors for the at least two objects;

means for computing relative speeds of the at least two objects;

means for computing a violation interval of at least two objects; and

means for performing an interval overlap check.

9. The apparatus of claim 8 wherein the means for interpolating the positions and altitudes of the at least two objects comprises:

means for retrieving the positions, altitudes and time of the current and previous scans of the at least two objects;

means for computing the increments in the targets system-plane positions and altitudes; and

means for synchronizing the targets positions and altitudes.

10. The apparatus of claim 8 wherein the means for computing the relative speeds of the at least two objects comprises:

means for computing an approach speed;

means for computing a head-on speed; and

means for computing a vertical speeds.

11. The apparatus of claim 8 wherein the means for computing the violation interval of at least two objects comprises:

means for computing a violation start time; and

means for computing a violation end time.

12. An air traffic control system comprising:

a radar system; and

a conflict alert processor coupled to said radar system, said conflict alert processor including;

a maneuver conflict alert prediction (MANCONP) processor which provides a reliable prediction of MSS violations; and

a proximity conflict (PROCON) processor coupled to said maneuver conflict alert prediction processor, said proximity conflict (PROCON) processor for maintaining a conflict alert until the aircraft for which the alarm is generated begin to diverge.

13. The air traffic control system of claim 12 wherein said maneuver conflict alert prediction processor comprises:

(a) an interval overlap processor;

(b) a separation criteria processor coupled to said overlap processor; and

(c) a convergence processor coupled to said separation criteria processor.

14. The air traffic control system of claim 12 wherein said maneuver conflict alert prediction processor comprises means for shortening the warning time during which a conflict alert becomes declarable.

15. The air traffic control system of claim 12 wherein said maneuver conflict alert prediction processor comprises:

first means for placing the start time of a horizontal violation within a time interval bounded by the earliest and latest times that such an MSS violation could start;

second means for computing the corresponding end times, wherein the two start-and-end-time pairs define the two intervals during which the fastest and slowest approaches would each be in violation; and

third means for determining if both intervals overlap each other and they also overlap the interval during which the aircraft pair will be in vertical violation such that there exists a potential for conflict and a hit can be logged.

16. The air traffic control system of claim 12 wherein said first means obtains the earliest time by assuming the fastest possible approach and the latest time by assuming the slowest possible approach.