GROUND-BASED VIDEOMETRICS GUIDING METHOD FOR AIRCRAFT LANDING OR UNMANNED AERIAL VEHICLES RECOVERY

• US 20120075461A1
• Filed: 03/27/2009
• Published: 03/29/2012
• Est. Priority Date: 03/27/2009
• Status: Active Grant

• Current Assignee: National University of Defense Technology
• Original Assignee: National University of Defense Technology
• Inventors: Yu, Qifeng, Lei, Zhihui, Zhang, Xiaohu, Shang, Yang, Zhang, Heng, Zhou, Xiang
• Granted Patent: US 9,057,609 B2
• Time in Patent Office: Days
• US Class Current: 348/117
• CPC Class Codes: B64U 70/60 Take-off or landing of UAVs from a runway using their own power
• CPC Class Codes: G01C 11/00 Photogrammetry or videogrammetry, e.g. stereogrammetry; Photographic surveying
• CPC Class Codes: G01C 21/10 by using measurements of speed or acceleration G01C21/24, G01C21/26 take precedence
• CPC Class Codes: G01S 5/16 using electromagnetic waves other than radio waves
• CPC Class Codes: G05D 1/0676 specially adapted for landing
• CPC Class Codes: G08G 5/0026 located on the ground
• CPC Class Codes: G08G 5/025 Navigation or guidance aids radar or analogous systems specially adapted for landing purposes G01S13/913

Abstract

The present invention provides a ground-based camera surveying and guiding method for aircraft landing and unmanned aerial vechicle recovery based on the camera surveying technology, which is a ground-based camera surveying and guiding system mainly including several video cameras arranged near the landing areas of an aircraft or an unmanned aerial vechicle. During the approaching process of the aircraft or the unmanned aerial vechicle, the system performs imaging of the aircraft in real time and detects movement parameters such as the track, velocity, acceleration, attitude and the offset relative to the glide slope of the aircraft or the unmanned aerial vechicle in real time by analyzing images and applying camera surveying method and technology, so as to provide guidance for aircraft landing or unmanned aerial vechicle recovery. The method is an autonomic guiding survey without interferences from others, which has high accuracy and reliability. The hardware devices are mature, simple and have low cost. The devices are moveable and versatile, and can be used in aircraft landing aid, unmanned aerial vechicle recovery and the like.

Claims

1. A ground-based camera surveying and guiding method for aircraft landing and unmanned aerial vechicle recovery guidance, characterized in that, the method comprises:

(1) arranging a video camera near the landing areas of an aircraft or an unmanned aerial vechicle, the field of view of the video camera covering the flying survey area where the aircraft approaches;

(2) after field installation and adjustment of the video camera is completed, calibrating video camera parameters;

(3) when surveying is initiated, starting to acquire images of the survey area and detect a target in real time;

(4) when the aircraft or the unmanned aerial vechicle is detected to have entered the survey area, starting to identify and extract the moving target features and compute a three-dimensional position in real time and an attitude of the aircraft, and providing guidance for aircraft landing or unmanned aerial vechicle recovery by computing the track, velocity and acceleration of the aircraft through data filtering.

2. The ground-based camera surveying and guiding method for aircraft landing and unmanned aerial vechicle recovery guidance of claim 1, characterized in that during the survey process of identifying and extracting the target features in real time, a laser distance measuring instrument installed at the site of the video camera is used at the same time for measuring a relative distance from the aircraft in real time, so as to modify survey results of the target features.

3. The ground-based camera surveying and guiding method for aircraft landing and unmanned aerial vechicle recovery guidance of claim 1, characterized in that the target feature data identified and extracted in real time are transferred to a computer used for image extraction, control and parameter computation, so as to perform the computation and provide the guidance.

4. The ground-based camera surveying and guiding method for aircraft landing and unmanned aerial vechicle recovery guidance of claim 1, characterized in that the video camera is arranged near the landing areas of the aircraft or the unmanned aerial vechicle through one of the following methods:

a. fixing and installing fixed-focus video cameras at both sides of the landing runway, the intersected field of view of the video cameras at both sides of the runway covering the flying area where the aircraft approaches according to the guiding requests; and

arranging multiple sets of fixed and installed fixed-focus video cameras for narrow and long survey areas, wherein each set of the fixed-focus video cameras comprises at least two fixed-focus video cameras, and the video cameras at both sides of the runway are respectively intersected to cover the survey areas from far and near;

b. respectively installing a tripod head for monitoring at both sides of the landing runway, each tripod head having a zooming video camera installed thereon; and

according to the guiding requests, during the approaching process of the aircraft, scanning and covering the flying survey area through the intersected field of view of the two video cameras as the aircraft moves by controlling the rotation of the tripod head and the zooming of the video camera;

c. respectively fixing and installing fixed-focus video cameras at more than two sites on one side of the landing runway, the intersected field of view of the video cameras at multiple sites covering the flying survey area where the aircraft approaches according to the guiding requests; and

arranging multiple sets of fixed and installed fixed-focus video cameras for narrow and long survey areas, wherein the video cameras at the multiple sites are respectively intersected to cover the survey areas from far and near;

d. respectively installing a tripod head for monitoring at two sites on one side of the landing runway, each tripod head having a zooming video camera installed thereon; and

according to the guiding requests, during the approaching process of the aircraft, scanning and covering the flying area through the intersected field of view of the two video cameras as the aircraft moves by controlling the rotation of the tripod head and the zooming of the video camera;

e. installing a video camera at the median line of the runway, wherein the video camera directs to the area where the aircraft approaches, and the optical axis of the video camera overlaps the median line of the glide slope.

5. The ground-based camera surveying and guiding method for aircraft landing and unmanned aerial vechicle recovery guidance of claim 1 or 4, characterized in that when multiple sets of fixed and installed fixed-focus video cameras are respectively used for surveying different survey areas from far and near, the survey areas are divided into multiple areas for arranging surveying video camera sets respectively;

first a distant-field video camera acquires images and detects the target in real time, identifies and extracts target features after the target is found, and then computes movement parameters of the target;

when it is computed that the target has entered the intersected survey area of the middle-field video camera, a switch command is sent, so that the middle-field video camera is switched to acquire images and detect the target in real time, identify and extract target features, and compute the movement parameters of the target; and

the rest can be deduced by analogy, and the guiding survey is completed when the target moves away from the area on demand of guiding survey.

6. The ground-based camera surveying and guiding method for aircraft landing and unmanned aerial vechicle recovery guidance of claim 1 or 4, characterized in that when the zooming video camera is used or the tripod head controls the direction of the video camera, first the video camera directs to the starting position of the survey area, acquires images and detects the target in real time, identifies and extracts target features after the target is found, and computes the movement parameters of the target;

according to the target position and the result of velocity computation, the rotation angle and velocity of the tripod head are controlled, and the focal length of the video camera is adjusted, so as to ensure that a clear image of the target is formed in the field of view of the video camera;

in the overall process, the target features are identified and extracted, the target movement parameters are computed and the rotation of the tripod head and the zooming of the video camera lens are controlled in real time; and

the guiding survey is completed when the target moves away from the area on demand of guiding survey.

7. The ground-based camera surveying and guiding method for aircraft landing and unmanned aerial vechicle recovery guidance of claim 1 or 4, characterized in that when a single video camera is used for surveying and the center area of the image corresponds to the glide slope, the target features are identified and extracted after the target is found;

the direction and angle of the aircraft deviated from the median line of the glide slope are computed and whether the aircraft is on the glide slope is determined according to the direction and distance of the target on the image deviated from the image center.