A Method for Determining the Horizontal Attitude of Aircraft Based on Skyline Imaging
A technology of horizontal attitude and determination method, applied in the field of aircraft navigation, which can solve problems such as error and limited accuracy
Active Publication Date: 2016-03-30
NAT UNIV OF DEFENSE TECH
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[0005] There are two problems in the above-mentioned aircraft attitude determination method based on skyline imaging: first, the assumption that the projection of the skyline on the image is regarded as a straight line is not valid. The relevant strict quadratic curve and straight line assumptions have non-negligible errors under the conditions of high-altitude aircraft and large field of view imaging; second, the horizontal attitude angle obtained from the above image is actually only the attitude of the camera in the horizontal coordinate system, because It is impossible for the camera to be completely coaxial with the aircraft. Using the horizontal attitude of the measuring camera as the horizontal attitude of the aircraft has certain errors and the accuracy is limited.
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[0068] Using the present invention to detect the skyline on the image taken by the camera and apply it to the measurement of the horizontal attitude of the aircraft, the specific steps are as follows:
[0069] The first step is to establish a coordinate system
[0070] 1.1 Establish camera coordinate system F and image plane coordinate system
[0071] 1.2 Establish aircraft body coordinate system F1
[0072] The second step is to detect the image contour
[0073] 2.1 Extract the image contour point coordinates and record them as a set .
[0074] 2.2 The neutron sets are sorted from the largest to the smallest according to the length, and recorded as .
[0075] The third step is to detect the skyline
[0076] 3.1 Selection Subsets of length greater than L form a collection , using the least squares algorithm to obtain the coefficients of M quadratic curves , , , , value.
[0077] 3.2 Computing Sets Separately The distances from all image contour p...
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The invention discloses an aircraft horizontal attitude determination method based on skyline imaging. The method comprises the steps of determining candidate skyline projection curves by a process of repeatedly selecting interior point fitting secondary curves by use of the detected image edge coordinates; then, selecting a correct skyline projection curve by a process of comparing the statistical values of the regional gray level, and calculating the horizontal attitude angle of a camera; finally, obtaining the aircraft horizontal attitude angle through the installation relationship. Compared with the method of assuming that the skyline is imaged into a straight line in the prior art, the method disclosed by the invention adopts the strict skyline extracted by a secondary curve model so as to better conform to the practical physical essence; moreover, compared with the way of directly using the measured value of the horizontal attitude of the camera as the horizontal attitude information of a carrier, the method introduces the installation relationship between the camera and the coordinate system of the aircraft body so that the camera is more flexible to install.
Description
technical field [0001] The invention belongs to the field of aircraft navigation, in particular to a method for determining the attitude of an aircraft based on skyline imaging. Background technique [0002] Aircraft attitude information not only plays a vital role in the flight control of the aircraft itself, but also is critical data in ground positioning and navigation. For example, the processing of laser ranging data must introduce aircraft attitude information to obtain a real-time terrain height map that can be used for terrain matching. At present, the conventional aircraft attitude measurement is to obtain the flight attitude through the integral calculation of angular velocity or angular acceleration, which belongs to the inertial navigation method. The measurement equipment is large in size and weight, and the measurement process is prone to large error accumulation. The aircraft attitude measurement method based on visual imaging only needs passive imaging equip...
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IPC IPC(8): G01C21/00G01C21/20
CPCG01C21/00G01C21/20G06T7/10
Inventor 刘海波张小虎于起峰苏昂张跃强陈圣义
Owner NAT UNIV OF DEFENSE TECH