JPH07329897A - Attitude decision device of spacecraft - Google Patents

Abstract

PURPOSE:To carry out triaxial attitude decision of a spacecraft without using an earth sensor and a solar sensor. CONSTITUTION:A yaw angle is detected by a two-dimensional Fourier transformation device 15 applying Fourier transformation to a ground picture image obtained by a picture image take-up device 13 and comparing its amplitude component with a Fourier amplitude component of a reference picture image previously stored in a picture image data base 14. Additionally, a roll angle and a pitch angle are detected by rotationally correcting the ground picture image and moving it in parallel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for determining the attitude of a spacecraft including artificial satellites.

[0002]

2. Description of the Related Art FIG. 1 shows a conventional attitude determining device for directing the sun. In the figure, 1 is an earth sensor that detects the roll angle of the spacecraft by detecting the infrared rays of the earth, 2
Is a sun sensor that detects the pitch angle and yaw angle of the spacecraft by capturing the position of the sun. 3, 4, 5 are gyros that detect roll angular velocity, pitch angular velocity, and yaw angular velocity, respectively, 6, 7, and 8 are gyros. Earth sensor roll angle output and roll angle estimated value, sun sensor pitch angle output and pitch angle estimated value, sun sensor yaw angle output and gain multiplied by the difference between yaw angle estimated value, 9, 10 and 11 respectively roll It is an integrator for angles, pitch angles, and yaw angles. Next, the operation will be described. Spacecraft roll and pitch angles detected by Earth sensor 1 and Sun sensor 2,
From the yaw angle (however, the signal from the earth sensor can be acquired only once per revolution because it is oriented toward the sun), the roll angle estimated value, the pitch angle estimated value, and the yaw angle estimated value are subtracted, and gains 6, 7 and You can multiply by 8. Those signals are
Correct the drift components of gyros 3, 4, and 5. The corrected gyro output signal is integrated by the integrators 9, 10 and 11, and becomes a roll angle estimation value, a pitch angle estimation value, and a yaw angle estimation value, respectively.

[0003]

[Problems to be Solved by the Invention]
It is an essential element for the mission of spacecraft.
However, in the conventional structure, when one sensor fails, one attitude angle is always lost. Therefore, it has been an important task to determine the postures of all three axes with one device in the sense of ensuring the redundancy of posture determination as much as possible.

The present invention has been made to solve the above problems, and an object of the present invention is to obtain a posture determining apparatus for a spacecraft capable of determining the postures of three axes without using a sun sensor and an earth sensor.

[0005]

A spacecraft attitude determination device according to the present invention is mounted on a spacecraft, and is an image acquisition device for capturing a ground image, reference data of the ground image, and a two-dimensional Fourier transform of the image. Image data in which the stored data is stored in advance, a two-dimensional Fourier transform device for performing a two-dimensional Fourier transform of the image data acquired by the image acquisition device, and two data stored in the image database.
A two-dimensional Fourier amplitude component comparison device for comparing amplitude components of the two-dimensional Fourier transform data of the two-dimensional Fourier transform device and the two-dimensional Fourier transform data of the two-dimensional Fourier transform device and outputting a rotation angle corresponding to the difference as yaw angle reference data; When there is a difference between the amplitude components by the three-dimensional Fourier amplitude component comparison device, an original image rotation device that rotates the original image acquired by the image acquisition device, and an original image that is rotationally corrected by the original image rotation device. The original image translating device for translating an image is compared with the original image data stored in the image database and the translated original image data, and the original image translating device is driven to eliminate the difference. However, it is provided with an original image comparison device which outputs pitch angle and roll angle reference data corresponding to the parallel movement distance.

The spacecraft attitude determination device according to the present invention is mounted on the spacecraft, and includes an image acquisition device for capturing a ground image and a plurality of data obtained by translating the reference data of the ground image at predetermined intervals. Two-dimensional Fourier transform of the image data acquired by the image acquisition device and the image database in which the two-dimensional Fourier transform data of a plurality of images obtained by rotating the reference data of the ground image by a predetermined angle are stored in advance. And a plurality of two-dimensional Fourier transform data stored in the image database and the amplitude components of the two-dimensional Fourier transform data of the two-dimensional Fourier transform device are simultaneously compared in parallel to obtain the most difference. A two-dimensional Fourier amplitude component parallel type comparison device which detects a small image and uses a rotation angle corresponding to the image as a yaw angle; The original image rotating device for rotating the original image from the two-dimensional Fourier transform unit by the output of the compare unit,
The reference image with the smallest difference is detected by comparing the original image rotated by the original image rotation device with a plurality of parallel displacement data stored in the image database, and the parallel displacement distance with respect to the image is detected. And an original image comparison device for outputting reference data of roll angle and pitch angle corresponding to.

A spacecraft attitude determination device according to the present invention comprises:
A gyro device that detects the roll angular velocity, pitch angular velocity, and yaw angular velocity of a spacecraft, and the roll angular velocity, pitch angular velocity, and yaw angular velocity detected by the gyro device are corrected using the roll angle, pitch angle, and yaw angle reference data. , Roll angle, pitch angle, yaw angle estimated value calculation means.

[0008]

According to the present invention, the image data acquired by the image acquisition device at a predetermined position on the trajectory is Fourier transformed by the two-dimensional Fourier transform device. Then, it is compared with the reference image data that would look like that if the posture is correct in the two-dimensional Fourier amplitude component comparison device. The important point here is that the amplitude component of the two-dimensional Fourier transform is insensitive to the parallel movement of the image, and therefore it is possible to extract the information of only the rotation angle. When the difference is detected by the two-dimensional Fourier amplitude component comparison device, the original image rotation device rotates the original image. This is repeated to find the rotation angle that matches the Fourier amplitude component data of the reference image. This rotation angle corresponds to the yaw angle of the spacecraft.
The original image with the corrected rotation angle is translated by the original image translation device and compared with the original image data stored in the image database by the original image comparison device. If there is a difference as a result of comparison, further parallel movement is performed and this operation is repeated until the difference falls within the allowable range. The magnitude of this parallel movement corresponds to the roll angle and pitch angle of the spacecraft.

Further, according to the present invention, a Fourier transform image of a plurality of images obtained by rotating the original image for each minute angle and a plurality of images obtained by moving the original image in parallel for each minute distance are prepared in advance as data. Store in the database. The image obtained from the image acquisition device is two-dimensional Fourier transformed by the Fourier transform device. The Fourier amplitude component is simultaneously compared in parallel by a comparator with a plurality of data stored in advance in a database and rotated for each minute angle.
As a result, the rotation angle at the best fit is the yaw angle.
Create an image of the original image rotated by the yaw angle with the original image rotation device,
Then, the reference original image is compared with a plurality of data obtained by moving the reference original image in parallel at the same time by a comparator. As a result, the amount of parallel movement corresponding to the most fitted image corresponds to the roll angle and the pitch angle.

According to the present invention, the output of the gyro device is corrected by using the reference data of roll angle, pitch angle and yaw angle.

[0011]

【Example】

Example 1. Example 1 will be described with reference to FIG. FIG. 1 shows an embodiment of the invention according to the present invention. A spacecraft attitude determination apparatus according to the present invention includes an image acquisition apparatus 13 for acquiring a ground image, an image database 14 for storing reference data, and an acquired image. A two-dimensional Fourier amplitude component comparison device 16 for comparing the two-dimensional Fourier transform device 15, the amplitude component of the Fourier transform image, and the Fourier transform data of the reference data accumulated in the database 14.
The original image rotating device 17 for rotating the original image according to the result of the comparison, the original image parallel moving device 18 for moving the rotation-corrected original image in parallel, the translated original image and the database 1
4 is composed of an original image comparison device 19 for comparing the reference original images accumulated in No. 4. These operate as follows.

The state of data processing is schematically shown in FIG. 2, which will be described accordingly. The image acquisition device 13 acquires the ground image a2 at a predetermined position. The image acquisition device in this case is, for example, a device such as a synthetic aperture radar, and is capable of capturing even fine irregularities on the ground. On the other hand, the image database 14 stores in advance a ground image (original image reference data a1) when the posture is normal and data (b1) obtained by two-dimensional Fourier transforming it.
The image data acquired by the image acquisition device 13 is Fourier transformed by the two-dimensional Fourier transform device 15 (b
2). The amplitude component of the Fourier transform and the amplitude component of the Fourier transform of the reference data obtained in the normal posture from the predetermined position accumulated in the image database 14 are 2
The two-dimensional Fourier amplitude component comparison device 16 compares them. As a method of comparison, a method of using the sum of squares of the differences between the components as an index and the like can be considered. Here, the fact that the amplitude component of the two-dimensional Fourier transform of the image is insensitive to the rotational movement is used. That is, if the original image is g (x, y) and the two-dimensional Fourier transform image of the original image is G (u, v)

[0013]

[Equation 1]

[0014] If the Fourier transform image of the image obtained by translating the original image by Δx and Δy is G ′ (u, v),

[0015]

[Equation 2]

Next to

[0017]

[Equation 3]

From the above, it can be seen that the amplitude component of the Fourier transform image is insensitive to the parallel movement of the original image.

The above two-dimensional Fourier amplitude component comparison device 16
If there is a difference as a result of the comparison, the same procedure of rotating the original image by a small angle by the original image rotating device 17 and performing two-dimensional Fourier transform on the original image and comparing it with the reference is repeated. Finally, when the Fourier amplitude component agrees with the reference (or the difference is equal to or less than the allowable value) by the comparison in the comparator, it becomes c in FIG. 2 and the angle rotated up to that point becomes the yaw angle. The original images (d) and (e) whose rotations are corrected are used as the original image translation device 17
Is moved in parallel (f) by the above, and the original image data of the reference is compared with the original image comparison device 18. This operation is repeated until the comparison matches. The amount of parallel movement when they finally match corresponds to the roll angle and the pitch angle. By using the method as described above, the postures of all three axes can be determined by a single device.

Example 2. FIG. 3 is a diagram showing a second embodiment of the present invention, in which an inertial navigation device is added to the configuration of the first embodiment shown in FIG. The inertial navigation system includes a gyro 3 for measuring roll angular velocity, a gyro 4 for measuring pitch angular velocity, a gyro 5 for measuring pitch angular velocity, integrators 9, 10, 11 and an integrator 9 for integrating angular velocity corrected by reference data. It is composed of roll, pitch, and yaw gains 6, 7, and 8 applied to the difference between the outputs of 10 and 11 and the reference data.

The image acquisition device 13 acquires an image of the ground at a predetermined position. The image data is Fourier transformed by the two-dimensional Fourier transform device 15. The comparator 16 compares the amplitude component of the Fourier transform with the amplitude component of the Fourier transform of the reference data obtained in the normal posture from the predetermined position stored in the image database. If there is a difference as a result of the comparison, the original image rotation device 17
Then, the original image is rotated by a small angle, a two-dimensional Fourier transform is performed on the original image, and the same procedure of comparing with the reference is repeated. Finally, if the Fourier amplitude component matches the reference (or the difference is equal to or less than the allowable value) by the comparison in the comparator, the angle rotated up to that point becomes the yaw angle reference. The original image of which the rotation amount has been corrected is translated by the original image translation device 18, and the original image data of the reference is compared by the original image comparison device 19. This operation is repeated until the comparison matches. The amount of parallel movement when they finally match corresponds to the roll angle reference and the pitch angle reference. This roll angle, pitch angle, yaw angle reference and the output difference of the integrators 9, 10, 11 are multiplied by gains 6, 7, 8 and input to the integrators 9, 10, 11 for roll, pitch,
The angular velocity output of the yaw gyro is corrected, and the estimated values of roll angle, pitch angle, and yaw angle are calculated. However, the inertial navigation device is not limited to this type.

Example 3. A third embodiment will be described with reference to FIG. FIG. 4 is a diagram showing a third embodiment according to the present invention. An image acquisition device 13 for acquiring a ground image, an image database 14 including a plurality of data obtained by processing a reference image in advance, and a Fourier transform of the acquired original image. Two-dimensional Fourier transform device 15 and a plurality of two-dimensional Fourier amplitude component parallel type comparison devices for comparing the amplitude component of the Fourier transform image and the amplitude component of the Fourier transform image of the plurality of reference original images processed independently in advance. 19, an original image rotation device 17 for rotating the original image, and an original image parallel type comparison device 28 for simultaneously comparing the rotationally corrected original image and a plurality of reference original images processed independently beforehand. These operate as follows.

Unlike the first and second embodiments, as shown in FIG. 5, the image database 14 has Fourier transform images b1 to b1 of a plurality of images obtained by rotating the reference original image photographed from a predetermined position for each minute angle. A plurality of data a1 obtained by moving the amplitude component of bN and the reference original image in parallel for each minute distance.
~ AN is stored in advance. The image acquisition device 13 acquires ground image data at a predetermined position. The image data is Fourier transformed by the Fourier transform device 15. The amplitude component of this Fourier transform and the Fourier transform amplitude component data of a plurality of reference images that have been rotated by a small rotation angle in advance are compared in parallel by the two-dimensional Fourier amplitude component parallel type comparison device 19. This two-dimensional Fourier amplitude component parallel type comparison device 19 has the first and second embodiments as shown in FIG.
A plurality of the two-dimensional Fourier amplitude component comparison devices 16 shown in FIG. 2 are arranged, and the smallest value difference is detected by the minimum value detection device 21, and the image / yaw angle selection device is detected. It is a mechanism to select by 22. The rotation angle corresponding to the image with the smallest difference in this comparison is the yaw angle of the spacecraft. The original image of which the rotation amount has been corrected is compared with the reference original image which is stored in the image database in parallel by a small distance in parallel and is compared in parallel with the original image parallel comparison device 20. The original image side-by-side comparison device 29 has a configuration in which a plurality of the original image comparison devices 19 shown in Embodiments 1 and 2 are arranged side by side as shown in FIG. Is detected by the minimum value detection device 21, and is selected by the pitch angle / roll angle selection device 23. As a result of this comparison, the parallel movement distance with respect to the reference original image having the smallest difference corresponds to the roll angle and the pitch angle of the spacecraft.

Example 4. A fourth embodiment will be described with reference to FIG. FIG. 8 shows an embodiment of the present invention. Unlike the first and second embodiments, as shown in FIG. 5, the image database 14 has Fourier transform images b1 to b of a plurality of images obtained by rotating the reference original image when photographed from a predetermined position for each minute angle.
A plurality of pieces of data a1 to aN obtained by translating the amplitude component of N and the reference original image in parallel for each minute distance are stored in advance. The image acquisition device 13 acquires ground image data at a predetermined position. The image data is Fourier transformed by the Fourier transform device 15. The amplitude component of this Fourier transform and the data of the reference image that has been rotated by a small rotation angle in advance are simultaneously compared in parallel by the two-dimensional Fourier amplitude component parallel type comparison device 28. The two-dimensional Fourier amplitude component parallel type comparison device 28 is used in the first and second embodiments as shown in FIG.
A plurality of the two-dimensional Fourier amplitude component comparison devices 16 shown in FIG. 3 are arranged, and the one having the smallest difference as a result of the comparison is detected by the minimum value detection device 21, and the image / yaw angle selection device is detected. It is a mechanism to select by 22. The rotation angle corresponding to the image with the smallest difference in this comparison is the yaw angle reference of the spacecraft.

The original image with the corrected rotation amount is compared with the reference original image, which has been stored in the image database in parallel by a small distance, in parallel with the original image parallel type comparison device 29. The original image side-by-side comparison device 29 has a configuration in which a plurality of the original image comparison devices 19 shown in Embodiments 1 and 2 are arranged side by side as shown in FIG. Is detected by the minimum value detection device 21, and is selected by the pitch angle / roll angle selection device 23. As a result of this comparison, the parallel movement distance to the reference original image having the smallest difference corresponds to the roll angle reference and the pitch angle reference of the spacecraft. The signals obtained by multiplying the outputs of the roll angle, pitch angle, yaw angle references and the integrator by gains 6, 7, and 8 are integrators 9, 10, and 1.
Input to 1 to correct the angular velocity output of the roll, pitch, and yaw gyros, and calculate the estimated values of the roll angle, pitch angle, and yaw angle. However, the inertial navigation device is not limited to this type.

[0026]

As described above, according to the present invention, it is possible to determine the postures of three axes by one device, which is realized by combining a plurality of sensors in the conventional sensor.

According to the present invention, it is possible to process the reference data in advance and compare them in parallel at the same time to speed up the posture determination.

According to the present invention, the attitude determining function can be maintained by integrating the gyro output while the ground is not observable.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram for explaining data processing according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram showing a second embodiment of the present invention.

FIG. 4 is a configuration diagram showing a third embodiment of the present invention.

FIG. 5 is a diagram for explaining a database according to the third embodiment of the present invention.

FIG. 6 is a configuration diagram showing a two-dimensional Fourier amplitude component parallel type comparison device according to a third embodiment of the present invention.

FIG. 7 is a block diagram showing an original image parallel type comparison apparatus according to Embodiment 3 of the present invention.

FIG. 8 is a configuration diagram showing a fourth embodiment of the present invention.

FIG. 9 is a diagram showing a conventional attitude determination device for a spacecraft.

[Explanation of symbols]

 3 gyro 4 gyro 5 gyro 6 gain 7 gain 8 gain 9 integrator 10 integrator 11 integrator 13 image acquisition device 14 image database 15 two-dimensional Fourier transform device 16 two-dimensional Fourier amplitude component comparison device 17 original image rotation device 18 original image Translation device 19 Original image comparison device 21 Minimum detection device 22 Image yaw angle selection device 23 Pitch angle / roll angle selection device 28 Two-dimensional Fourier amplitude component parallel type comparison device 29 Original image parallel type comparison device

Claims (3)

[Claims] 1. An image acquisition device mounted on a spacecraft for photographing a ground image, an image database in which reference data of the ground image and data obtained by two-dimensional Fourier transforming the image are stored in advance, and A two-dimensional Fourier transform device for two-dimensional Fourier transforming image data acquired by the image acquisition device, two-dimensional Fourier transform data stored in the image database, and an amplitude component of the two-dimensional Fourier transform data of the two-dimensional Fourier transform device. And a two-dimensional Fourier amplitude component comparison device that outputs a rotation angle corresponding to the difference as yaw angle reference data and the two-dimensional Fourier amplitude component comparison device described above so that the difference disappears. An original image rotation device that rotates the original image acquired by the image acquisition device, and rotation correction by the original image rotation device. Image parallel moving device for moving the original image in parallel, and the original image parallel moving device for comparing the original image data stored in the image database with the translated original image data so as to eliminate the difference. Attitude determination device for a spacecraft, which includes a source image comparison device that drives the motor and outputs pitch angle and roll angle reference data corresponding to the parallel movement distance. 2. An image acquisition device mounted on a spacecraft for photographing a ground image, and a plurality of data obtained by translating the reference data of the ground image in parallel at a predetermined distance and the reference data of the ground image are rotated at a predetermined angle. An image database in which two-dimensional Fourier transform data of a plurality of images thus obtained are stored in advance, a two-dimensional Fourier transform device for two-dimensional Fourier transforming the image data acquired by the image acquisition device, and the image database The image having the smallest difference is detected by simultaneously and in parallel comparing the plurality of two-dimensional Fourier transform data stored in the two-dimensional Fourier transform data and the amplitude components of the two-dimensional Fourier transform data of the above-mentioned two-dimensional Fourier transform device, and corresponding to the image. A two-dimensional Fourier amplitude component parallel type comparison device having a rotation angle as a yaw angle, and the two-dimensional Fourier transform by the output of the comparison device. The difference between the original image rotating device for rotating the original image from the device and the original image rotated by the original image rotating device is compared with a plurality of data of parallel movement for each predetermined distance stored in the image database. Attitude determination device for a spacecraft, which includes a source image comparison device that detects a reference image having a small size and outputs reference data of a roll angle and a pitch angle corresponding to a parallel movement distance to the image. 3. A detection means for detecting the roll angular velocity, the pitch angular velocity and the yaw angular velocity of the spacecraft, and the roll angular velocity, the pitch angular velocity and the yaw angular velocity detected by said detection means are said roll angle, pitch angle and yaw angle reference data. The attitude determining apparatus for a spacecraft according to claim 1 or 2, further comprising means for calculating a roll angle, a pitch angle, and a yaw angle estimated value by using the above equation.