Flexible satellite-borne antenna on-orbit vibration measurement method based on sequence image

Abstract

The invention discloses a flexible satellite-borne antenna on-orbit vibration measurement method based on a sequence image, and the method comprises the steps: pasting a target mark point on a flexible satellite-borne antenna, carrying out the image collection according to the time sequence, and obtaining the sequence image of the flexible satellite-borne antenna; extracting target mark points from the sequence image of the flexible satellite-borne antenna to obtain the contour of each target mark point; fitting the contour of each target mark point into a sub-pixel precision ellipse, and determining the central pixel coordinate of each sub-pixel precision ellipse; establishing a camera projection model; according to the central pixel coordinates of each sub-pixel precision ellipse, calibrating the external parameters of the camera projection model to complete on-orbit calibration; and carrying out on-orbit vibration measurement on the target mark point pasted by the flexible satellite-borne antenna according to the camera projection model after the external parameters are calibrated. The measurement result provides input for antenna surface type fine tuning, vibration suppression,dynamic model on-orbit correction and load-to-ground imaging compensation, and meanwhile provides measurement and image information for satellite on-orbit fault diagnosis and on-orbit health monitoring.

Description

technical field [0001] The invention relates to an on-orbit vibration measurement method of a flexible space-borne antenna based on sequence images, belonging to the technical field of spacecraft dynamics. Background technique [0002] With the increasing application of satellites in earth exploration, radio astronomy, deep space communication, energy transmission, etc., flexible spaceborne antennas should be a main direction for the development of deployable antennas in the future. In the future, space-borne antennas will develop in the direction of lightweight, economical, multi-functional, agile and fast responding. Therefore, the spaceborne antenna structure has dynamic characteristics such as large span, light weight, low stiffness, and weak damping. It is a typical large-scale flexible space structure, which brings a series of dynamic and control problems to this type of spacecraft. In the future, more and more large-scale deployable antennas will be used on spacecraf...

AI Technical Summary

Problems solved by technology

[0003] The traditional contact measurement method needs to install sensors on the structure under test, such as acceleration sensors, piezoelectric ceramics, etc. This method has several disadvantages: 1) Due to the complex structure of the antenna equipment, the location and space of the sensor arrangement are limited; 2) As an additional mass, the sensor will change the mass distribution and structural stiffness of the antenna itself, thereby changing its dynamic characteristics and reducing the structural reliability; 3) Contact measurement may affect the working state of the antenna and interfere with its mission function

The current non-contact measurement methods mainly use camera vision measurement or laser radar measurement. The given method has several limitations: 1) Due to the large span of the antenna, in order to achieve long-distance measurement, binocular or multi-eye measurement methods are mostly used , but the depth resolution decreases in a quadratic relationship with the increase of the distance, which often fails to meet the measurement accuracy index requirements (millimeter level); , stress release and thermal deformation will change the calibration results before launch and affect the final measurement accuracy; 3) Laser 3D imaging has high ranging accuracy (sub-centimeter level), but the lateral resolution is low, requiring scanning mechanisms and existing Three-dimensional image motion distortion, suitable for medium and long-distance detection and quasi-stationary targets

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