Airborne obstacle collision avoidance apparatus

• US 5,448,233 A
• Filed: 01/27/1994
• Issued: 09/05/1995
• Est. Priority Date: 01/28/1993
• Status: Expired due to Term

• Current Assignee: Rafael - Armament Development Authority Ltd.
• Original Assignee: State of Israel Rafael Armament Development Authority
• Inventors: Faibish, Sorin, Saban, Izhak, Shamay, Ezra
• Primary Examiner(s): Swarthout, Brent
• Assistant Examiner(s): Lee, Benjamin C.
• Application Number:
  US08/186,959
• Time in Patent Office: 586 Days
• Field of Search: 340/961, 340/963, 340/990, 340/980, 364/461, 364/424.06, 364/449, 342/29, 342/32, 342/64, 342/63, 342/455, 244/76 R, 244/175
• US Class Current: 340/963
• CPC Class Codes: G01S 17/933 of aircraft or spacecraft
• CPC Class Codes: G01S 7/4802 using analysis of echo signal for target characterisation; Target signature; Target cross-section

Abstract

An airborne obstacle collision avoidance apparatus which includes an object sensor for sensing objects within a field of view of the aircraft and an aircraft navigation system for navigating the aircraft through space. The apparatus also includes a signal processor for receiving data from both the object sensor and the aircraft navigation system, for generating map data of the objects within the field of view of the aircraft, for dynamically changing the map data as the aircraft moves through space and for determining the probability that the aircraft is on a collision course with respect to each sensed object. The apparatus further includes an alarm which is activated when the signal processor determines that there is a high probability that the current aircraft flight direction is on a collision course with respect to a sensed object.

Claims

1. Airborne obstacle collision avoidance apparatus, comprising:

(a) object sensor means for sensing objects within a field of view of the aircraft;

(b) an aircraft navigation system for navigating the aircraft through space;

(c) signal processing means for receiving data from both the object sensor means and the aircraft navigation system, for generating map data of the objects within the field of view of the aircraft, for dynamically changing said map data as the aircraft moves through space, and for determining a probability that the aircraft is on a collision course with respect to each sensed object, said signal processing means further including a straight line filter to extract straight line features from said map data in order to facilitate identification of straight line obstacles, including electric cables and electric poles, said extraction of straight line features being based on the following straight line extraction criteria;

(1) slope of said straight line obstacle relative to ground;

(2) height of said straight line obstacle above ground;

(3) length of said straight line obstacle;

(4) number of said straight line obstacles sensed within said field of view of the aircraft; and

(5) continuity of said straight line obstacle; and

(d) alarm means for producing an alarm when said signal processing means determines there is a high probability that a current aircraft flight direction is on said collision course with respect to a sensed object.

2. The apparatus according to claim 1, wherein said alarm means includes a visual display, and display control means for visually displaying thereon the sensed objects and an indication of their probabilities of being located on said collision course with respect to the current flight direction of the aircraft.

3. The apparatus according to claim 2, wherein said display control means visually displays:

(i) in a first color, objects at a relatively large distance from the aircraft;

(ii) in a second color, objects that will become a danger of collision if no corrective action is taken; and

(iii) in a third color, objects which represent a danger to the aircraft and require corrective action.

4. The apparatus according to claim 3, wherein said signal processing means causes the display of said third color to blink with respect to objects which immediately require the corrective action to avoid a collision.

5. The apparatus according to claim 4, wherein said alarm means also includes a speaker for sounding an audio alarm when an object of said third color is caused to blink.

6. The apparatus according to claim 2, wherein said display control means also visually displays a range of each detected object having a high probability of being located on said collision course with respect to the current flight direction.

7. The apparatus according to claim 6, wherein said display control means also visually displays an azimuth and elevation, with respect to the current flight direction, of each detected object having a high probability of being located on said collision course with respect to the current flight direction.

8. The apparatus according to claim 2, wherein said display control means displays, in full lines, the sensed objects having a high probability of being located on said collision course with respect to the current flight direction, and in broken lines, spaced at a distance from said full lines of said sensed objects, an uncertainty region caused by measurement noise.

9. The apparatus according to claim 1, further including guidance command generator means for generating an emergency escape flight guidance path, and for displaying said path to the pilot, in the event said signal processing means determines there is a danger of an imminent collision with said sensed object.

10. The apparatus according to claim 9, wherein said aircraft includes an autopilot, and said guidance command generator means also generates emergency escape flight guidance commands for execution by the autopilot if validated by the pilot.

11. The apparatus according to claim 1, wherein said signal processing means processes said map data to establish a table classifying each detected object according to a range of the object, altitude of object with respect to the flight direction, probability of collision with the object, and quality of decision.

12. The apparatus according to claim 11, wherein said signal processing means generates, from the data in said table, three additional sub-tables that partition the data at least according to the following:

(A) a first sub-table, according to the ranges of all the objects included within a semi-sphere having a predetermined radius with the aircraft as its center;

(B) a second sub-table, according to the time-to-collision if the aircraft continues in the same flight direction and at the same velocity; and

(C) a third sub-table, illustrating the most dangerous object reflected by the other two sub-tables.

13. The apparatus according to claim 1, wherein said aircraft navigation system is an inertial navigation system.

14. The apparatus according to claim 1, wherein said signal processing means further includes means for processing said map data to define a boundary between the ground and the flight space.

15. The apparatus according to claim 1, wherein said obstacle sensor means includes an active electro-optical laser sensor measuring range and intensity.

16. The apparatus according to claim 1, wherein said obstacle sensor means includes an electromagnetic cable sensor.