JPH10185683A - Star sensor, and artificial satellite attitude control device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a star sensor capable of precisely detecting and controlling the attitude of a satellite and an artificial satellite attitude control device using it by correcting the dark output of a two-dimensional image pickup element by a highly reliable method, precisely detecting a star image position, and combining a plurality of image input parts with a signal processing part. SOLUTION: When the solar light reaches a two-dimensional image pickup element 105 through an optical system 102, a ND filter 103 is arranged on the optical path extending from the optical system to the two-dimensional image pickup element to attenuate the light quantity of the solar light passed through the optical system so as to have a proper exposing quantity of the two-dimensional image pickup element. When only a star image is formed on the two-dimensional image pickup element without the solar light, the ND filter is removed from the optical path to directly image the light converged by the optical system on the two-dimensional image pickup element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a star sensor mounted on a satellite for detecting the position of a star such as a star and measuring the attitude of the satellite, and an artificial satellite using a measurement output of the star sensor. The present invention relates to a posture control device that controls the posture of the vehicle.

[0002]

2. Description of the Related Art A star sensor that forms an image of a star on a two-dimensional image sensor and detects the attitude of the satellite uses an offset of the output of the two-dimensional image sensor that changes with temperature and aging.
That is, correcting the dark output was one of the major problems. In a conventional star sensor, for example,
As described in Japanese Patent Publication No. 226398, a shutter for blocking the light of a star was provided, and an image was input with the shutter closed to obtain a dark output of the star sensor and obtained with the shutter open. By subtracting the dark output from an image containing a star image, a star image with accurate luminance has been obtained.

Further, the conventional star sensor is assumed to be used in combination with another sensor such as a sun sensor, and has only a function of calculating an accurate attitude of a satellite from a star position. Further, the star sensor is configured to calculate the attitude of the satellite using only image information input from one image input unit. In the conventional star sensor, a satellite attitude calculation unit including a dedicated processor is provided for each star sensor.

[0004]

Since the conventional star sensor is configured as described above, it is necessary to open and close the shutter in order to correct the dark output of the two-dimensional image pickup device. There is a problem that the reliability of the sensor is reduced due to the repeated operation. In addition, since a satellite needs to be equipped with a sun sensor in addition to a star sensor, there is a problem that the cost is increased. Further, there is a problem that operation is restricted so that the sun or the like does not enter the visual field of the star sensor.

Further, in the conventional star sensor, a satellite attitude calculation unit including a dedicated processor is provided for each star sensor. Therefore, for an artificial satellite equipped with a plurality of star sensors for redundancy, a plurality of satellite attitudes are provided. Since a plurality of dedicated processors constituting the calculation unit are provided, there are problems such as an increase in size, weight, cost, and power consumption of the artificial satellite. Furthermore, since data transmission between the satellite attitude calculation unit and the satellite attitude control processor is required, there are problems such as limitations on the amount of transmission information and limitations on the transmission speed.

Further, in order to calculate the attitude of the satellite using the image input unit and the subsequent processing unit and generate an actuator drive signal for attitude control of the satellite, a plurality of sets of these image input units and processing units are prepared. Reliability was improved by using a redundant configuration. However, since the star image obtained by the multiple star sensors is different, the output of each processing system cannot be expected to exactly match even if all systems are normal. However, it is difficult to eliminate the output of this system and select the output of a normal system.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and can correct the dark output of a two-dimensional image sensor by a highly reliable method without using other sensors such as a sun sensor. The purpose is to provide a star sensor that can detect the direction of the sun and calculate the attitude of the satellite using a single star sensor, and to reduce operational constraints by providing multiple image input units. And

Another object of the present invention is to reduce the size, weight, cost, and power consumption of a star sensor device and an artificial satellite as a whole in a satellite equipped with a star sensor.

In order to improve fault tolerance, the attitude of the artificial satellite is calculated using a plurality of star sensors to generate an actuator drive signal for controlling the attitude of the artificial satellite. It is an object of the present invention to provide a satellite attitude control device capable of reliably selecting an output of a system to perform.

[0010]

A star sensor according to a first aspect of the present invention comprises an optical system for condensing the light of a star or the sun, and an optical system for converting the light condensed by the optical system into an electric signal. An image input unit having a two-dimensional image sensor, and a star sensor having a data processing device for processing a signal output from the two-dimensional image sensor, the ND filter attached so that the position can be changed by a positioning device, In the case where sunlight is reaching the two-dimensional image sensor through the optical system, the ND filter is arranged on an optical path from the optical system to the two-dimensional image sensor. Attenuate the amount of sunlight passing through the two-dimensional image sensor to an appropriate exposure amount, if there is no sunlight and only a star image is formed on the two-dimensional image sensor, the above-mentioned ND The light condensed by the optical system removed from the optical path a filter is intended to be imaged directly on the two-dimensional imaging element.

A star sensor according to a second aspect of the present invention includes a lens attached to the image input unit so that the position can be changed by a positioning device, and sunlight reaches the two-dimensional image sensor through an optical system. If you have
In addition to the ND filter, the lens is also arranged on the optical path from the optical system to the two-dimensional image sensor.

A star sensor according to a third aspect of the present invention is an optical system for condensing star light and a two-dimensional optical system for converting a star image condensed by the optical system into an electric signal and sequentially outputting the electric signal as luminance data. In a star sensor including an image input unit having an image sensor and a data processing device for processing brightness data, the brightness data output by the two-dimensional image sensor is input, and the time constant is shorter than the measurement cycle of the star sensor. And a sufficiently long low-pass filter, and an image memory for storing the output of the low-pass filter.
Each time the luminance data is output, the corresponding data in the image memory is subtracted from the luminance data, and the result is input to the data processing device.

A star sensor according to a fourth aspect of the present invention is an optical system for condensing star light, and a two-dimensional optical system for converting a star image condensed by the optical system into an electric signal and sequentially outputting the electric signal as luminance data. A plurality of image input units each having an image sensor,
A multiplexer that receives the outputs of all the image input units and selects and outputs some of the plurality of inputs, and a process that receives the outputs of the multiplexers and calculates the attitude of a satellite equipped with the image input unit The apparatus and a star image obtained by each of the image input devices are estimated from the calculated attitude of the satellite, and an image input unit expected to be able to measure the attitude of the satellite with the highest accuracy is selected. And an input image selecting section for outputting an instruction relating to the selection of the image input section to select the image input section.

A star sensor according to a fifth aspect of the present invention is an optical system for condensing star light, and a two-dimensional system for converting a star image condensed by the optical system into an electric signal and sequentially outputting the electric signal as luminance data. A plurality of image input units each having an image sensor are provided, at least one of which is an image input unit A mounted on the satellite after accurate mounting attitude adjustment with respect to the satellite, and the other is performed by a star sensor. An image input unit B attached to the satellite with lower accuracy than the accuracy, and a processing device that inputs the images captured by the image input unit A and the image input unit B at the same time and calculates the attitude of the satellite. A difference between the attitudes of the satellites obtained using the respective outputs of the image input unit A and the image input unit B, and the output of the attitude of the satellite obtained using the output of the image input unit B By adding the difference, the image input Is obtained so as to obtain the attitude of the satellite that fixes the error in the mounting posture of Part B.

A star sensor according to a sixth aspect of the present invention includes a plurality of optical systems each having an optical system for condensing star light and a two-dimensional imaging device for converting a star image condensed by the optical system into an electric signal. An image input unit, a plurality of memories respectively storing the images output from these image input units, and processing the image data stored in each of these memories to calculate the attitude of the satellite equipped with the image input unit A satellite attitude calculation unit having one star sensor processor for sending to the attitude control processor, and the satellite attitude calculation processing of the plurality of image input units is performed by the one star sensor processor.

A star sensor according to a seventh aspect of the present invention comprises a plurality of optical systems each having an optical system for condensing star light and a two-dimensional image sensor for converting a star image condensed by the optical system into an electric signal. , A plurality of memories respectively storing the images of these image input units, and processing the image data stored in these memories to calculate the attitude of the satellite equipped with the image input unit. A satellite attitude calculation unit including one attitude control processor; and the satellite attitude calculation processing of the plurality of image input units is performed by the one satellite attitude control processor.

A star sensor according to an eighth aspect of the present invention is an optical system for condensing star light and a two-dimensional optical system for converting a star image condensed by the optical system into an electric signal and sequentially outputting the electric signal as luminance data. A plurality of image input units each having an image sensor,
A plurality of star image processing units connected to each of the image input units to calculate the pixel coordinates of the star from the respective luminance data, and the attitude of the satellite on which the image input unit is mounted is determined from the processing results of these star image processing units. A plurality of posture determination units to be calculated;
The output of each of the star image processing units is input to all or a plurality of the plurality of attitude determining units, and the outputs obtained by performing the same processing in the plurality of attitude determining units are compared with each other. And a normal system determination unit for selecting the output of the normal system.

An attitude control apparatus for a satellite according to a ninth aspect of the present invention comprises an optical system for condensing star light, and a star image condensed by the optical system is converted into an electric signal and sequentially converted as luminance data. A plurality of image input units each having a two-dimensional imaging device for outputting, a plurality of star image processing units connected to each of the image input units and calculating pixel coordinates of a star from respective luminance data, and a star image processing unit A plurality of attitude determination units for calculating the attitude of the artificial satellite on which the image input unit is mounted from the processing result of the above, and connected to each of these attitude determination units in a one-to-one correspondence to the attitude control actuator from the attitude information. A plurality of control calculation units for respectively generating the drive command signals, and inputs the outputs of the star image processing units to all or a plurality of the plurality of attitude determination units. In the department The attitude determination section and a normal system determination section for selecting a normal system output of the control operation section by comparing the outputs of the control operation sections obtained by performing the same processing. is there.

An attitude control device for a satellite according to a tenth aspect of the present invention is an optical system for condensing star light, and a star image condensed by the optical system is converted into an electric signal and sequentially converted as luminance data. A plurality of image input units each having a two-dimensional image pickup device for outputting, a plurality of star image processing units connected to each of the image input units and calculating pixel coordinates of a star from respective luminance data; A plurality of attitude determination units that are connected in one-to-one correspondence with the units and calculate the attitude of an artificial satellite on which the image input unit is mounted based on the processing result, and from the attitude information of these attitude determination units to an attitude control actuator. A plurality of control operation units that respectively generate drive command signals of
The output of each of the attitude determining units is input to all or a plurality of the control arithmetic units, and the outputs obtained by performing the same processing in each of the plurality of control arithmetic units are compared to each other. And a normal system determination unit for selecting the output of the normal system.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a block diagram showing a configuration of a main part according to the first embodiment of the present invention. In the figure, reference numeral 101 denotes the entire image input unit. Reference numeral 102 denotes an optical system for condensing the light of a star or the sun, 105 denotes a two-dimensional image sensor such as a CCD for converting light condensed and formed by the optical system 102 into an electric signal, and 106 denotes a two-dimensional image sensor 105. It is a two-dimensional image sensor control circuit for operating. Reference numerals 103 and 104 denote an ND filter and a field-of-view expanding lens, respectively, which are disposed on or removed from the optical path from the optical system 102 to the two-dimensional image sensor 105 by a filter positioning mechanism 107.

Next, the operation will be described. During normal operation in which only star light enters the image input unit 101, ND
The filter 103 and the field-of-view expanding lens 104 are
Although it is arranged at a position that does not block the optical path from 02 to the two-dimensional image sensor 105, when the incidence of sunlight is detected,
The ND filter 103 and the field-of-view expanding lens 104 are moved on the optical path from the optical system 102 to the two-dimensional image sensor 105, and all the light imaged on the two-dimensional image sensor 105 passes therethrough. As a result, even when sunlight that is much stronger than the light of a star enters, an appropriate exposure state is secured, the direction of the sun is detected, and as a result, the attitude of the satellite can be detected. Furthermore, in order to obtain a star image, in order to suppress the attenuation of the amount of incident light, it is designed so that the hood attached to the outside of the optical system does not cause any eclipse. When strong light is incident on the light source, it is possible to secure a sufficient light quantity even if some blurring occurs. Therefore, by appropriately selecting the focal length of the field-of-view expanding lens 104 to be inserted together with the ND filter 103, even when sunlight enters from a direction in which some blur occurs, the image of the sun is displayed on the two-dimensional image sensor 105. Is formed, and the field of view that can be measured is expanded as compared with the case where the attitude of the satellite is measured from the star image.

As described above, according to the present embodiment, the ND filter 103 is connected to the optical system 102 when sunlight enters.
And between the two-dimensional image sensor 105 and appropriately attenuate the sunlight, an image of the sun is generated on the two-dimensional image sensor 105 in an appropriate exposure state, and the direction of the sun with respect to the satellite can be detected As a result, the attitude of the satellite can be measured. Further, in addition to the ND filter 103, a lens 104
And the optical path is bent to expand the viewing angle when measuring the direction of the sun.

Embodiment 2 FIG. When a star image is input by a star sensor, the area occupied by the star image is very small, and most of the area is a dark background. In addition, the attitude of the satellite in the low-orbit space with respect to the inertial space changes every moment, and as a result, the star image moves every moment on the two-dimensional image sensor 105. The second embodiment utilizes these characteristics. When a low-pass filter having a time constant sufficiently longer than the input period of an image is passed through each pixel obtained by the two-dimensional It is possible to obtain the luminance of the background without any. That is, it is possible to obtain the dark output of the two-dimensional image sensor 105 changed by the temperature change or the aging deterioration of the two-dimensional image sensor 105, and by subtracting this from the luminance data input from the two-dimensional image sensor 105, Accurate luminance of each pixel can be measured.

The second embodiment will be specifically described below with reference to the drawings. FIG. 2 is a block diagram showing a configuration of a star sensor according to a second embodiment of the present invention, and FIG. 3 is a flowchart illustrating an algorithm for updating a dark output according to the second embodiment. 2, reference numeral 101 denotes an image input unit; 110, an A / D converter that converts an analog luminance signal output from the image input unit into a digital luminance signal;
Is a subtraction unit for subtracting the dark output which is an offset component from the digitized image signal, 112 is an image memory for storing a luminance signal from which the dark output is removed by subtraction, and 113 is an image memory Satellite attitude calculation unit that processes the luminance signal stored in the satellite and calculates the attitude of the satellite, 114
A dark output updating unit 115 updates the dark output based on the luminance signal output from the subtracting unit 111 from which the dark output has been removed. 115 is a dark output for storing the dark output. The storage unit has the same size as the image memory 112.

Next, the operation will be described with reference to FIG.
Each time luminance data of one pixel is obtained from the image input unit 101, the following processing is performed. First, when a luminance signal of one pixel is output from the image input unit 101, the luminance signal is converted to an A / D converter 11
At 0, it is converted into a digital luminance signal (ST1). Next, the luminance signal is corrected by subtracting the dark output of the corresponding pixel stored in the dark output storage unit 115 (ST2), and the luminance signal is stored in the image memory 112 (ST3). Next, the following processing is performed by the dark output update unit 114 and the dark output storage unit 115. The elapsed time from when the dark output was last updated is checked (ST4), and if the elapsed time is less than a certain time (No in ST4), the process for the pixel is terminated and the process for the next pixel is performed. Work on. If a certain time has already passed (Ye in ST4)
In s), whether the corrected luminance signal is positive or negative is determined (S).
T5) The following processing is performed according to the result. However, it is assumed that the set time is sufficiently longer than the measurement cycle. When the corrected luminance signal is positive (Yes in ST5), the dark output stored in the dark output storage unit 115 is read, added with 1, and stored again (ST5).
6). If the corrected luminance signal is negative (No in ST5), conversely, 1 is subtracted from the dark output and stored (ST7). When the corrected luminance signal is 0, the update of the dark output is not performed. By changing the dark output one by one at certain time intervals, low-pass filter processing with a long time constant is realized. At any given moment, the brightness of one of the pixels may be high due to the light of the star, but the probability that the same pixel will continuously form a star image is very small, resulting in darkness in the background. You can get output. Here, a method of realizing a pseudo low-pass filter using digital processing has been described.
It may be realized by a complete low-pass filter by digital processing. Furthermore, even in the case of performing the update processing of the dark output, it is also possible to add a method of not performing the update processing on the pixel in which the star image is confirmed.

As described above, according to the present embodiment, the memory 11 for storing the dark output of the two-dimensional image sensor is stored.
5, the memory 115 stores a luminance signal output from the two-dimensional image sensor through a low-pass filter having a sufficiently long time constant as compared with the image input cycle. That is, by extracting the dark output of the two-dimensional image sensor and subtracting the dark output from the output of the two-dimensional image sensor, it is possible to obtain accurate brightness of the star image. improves.

Embodiment 3 FIG. 4 is a block diagram showing a configuration of a star sensor according to Embodiment 3 of the present invention.
Although there is no particular limitation on the number of image input units 101, FIG.
3 shows a case where three image input units 101 are provided. Reference numeral 122 denotes a multiplexer for selecting and outputting some of the luminance signals output from the three image input units 101. Reference numeral 121 denotes an input from each image input unit 101 based on the attitude of the satellite output from the satellite attitude calculation unit. An input image selection unit that estimates an image to be input and instructs the multiplexer 122 which image input unit 101 to select an image to be input.

Next, the operation will be described. In the first measurement, the multiplexer 122 is initialized,
One of the luminance signals output from the three image input units 101 is selected and output. Next, the A / D converter 11
At 0, the luminance signal is converted into a digital signal,
Stored in 2. The satellite attitude calculating unit 113 calculates the attitude of the satellite by processing the luminance signal. In the second and subsequent measurements, the input image prediction unit 121 uses the satellite attitude calculation unit 1
A star image detected by each image input unit 101 is predicted from the previous attitude of the satellite output from the unit 13 and the data of the distribution of stars stored in advance. Usually, since the measurement accuracy of the posture is improved as more bright stars are seen, the input image selector 121 does not interfere with the sun or the like among the three image input units, and furthermore, the image input that detects as many stars as possible. The unit determines which one
Give instructions to The multiplexer 122 selects one of the three inputs based on this instruction. After selecting the luminance signal by the multiplexer, the process of calculating the attitude of the satellite is performed in the same manner as the first measurement. In this case, three image input units 101 are provided, and the multiplexer 122
In the above description, one output is selected. However, according to the processing capability of the satellite attitude calculation unit 113 and the required measurement accuracy, for example, ten image input units 101 are provided. The number of the image input units 101 and the number of outputs of the multiplexer 113 can be set arbitrarily.

As described above, according to the present embodiment, a plurality of image input units 101 each having an optical system for inputting a star image and a two-dimensional image sensor are provided, and the attitude of the satellite obtained one time earlier is obtained. From the data, an image input by each image input unit 101 is predicted, and an image input unit 101 for which a highly accurate measurement result is expected
Is selected, and the attitude of the satellite is calculated using the output of the image input unit 101, so that the measurement accuracy is improved and, for example, sunlight or the like is used for some image input units 1
Even in the case of entering the field of view of 01, it is possible to predict the incidence of sunlight and measure stably by not using the image input unit 101 to which sunlight enters.

Embodiment 4 FIG. 5 is a block diagram showing a configuration of a star sensor according to Embodiment 4 of the present invention.
In FIG. 5, 101A is an image input unit whose mounting attitude has been accurately adjusted with respect to the satellite among the image input units mounted, and 101B is a particularly accurate image input unit among the mounted image input units. This is an image input unit that has not been adjusted in a proper mounting posture, and as a result is mounted in a state that includes an error in the mounting posture. Normally, if you do not adjust the mounting posture accurately just by fixing it mechanically,
A mounting error of about 0.5 to 1 degree occurs. 131 is 2
An alignment error calculator 13 for calculating the mounting error of the image input unit 101B including the mounting error from the satellite attitude data output from the satellite attitude calculators 113;
Reference numeral 2 denotes an alignment error correction unit that corrects satellite attitude data output from the satellite attitude calculation unit 113 based on output data from the alignment error calculation unit.

Next, the operation will be described. In the star sensor according to the present embodiment, after being launched on orbit,
The attitude of the satellite is calculated by inputting an image at the same time using both the image input units 101A and 101B. There is a difference between the obtained attitudes of the two satellites.
1B is the mounting error. Therefore, in the following measurement, the error of the mounting attitude obtained by the alignment error correction unit 132 is added to the measurement result of the attitude of the satellite obtained by using the image input unit 101B, so that the image input unit 101B is used. Also, it is possible to calculate the attitude of the satellite without mounting errors.

As described above, according to the present embodiment, at least one image input unit 101A of the plurality of image input units 101 is attached to the on-board equipment of the satellite by adjusting the attachment posture accurately. However, the other image input unit 101B is attached without performing particularly accurate adjustment of the attachment posture. As a result, for an image input unit having a reduced mounting accuracy, the satellite mounting cost can be reduced by correcting the mounting attitude using the result of actually inputting an image after launching the satellite and measuring the attitude of the satellite. In addition, since the deviation of the mounting posture due to the vibration at the time of launching is corrected, the requirement for the fixing method can be relaxed.

Embodiment 5 FIG. FIG. 6 is a block diagram showing a configuration of a star sensor according to Embodiment 5 of the present invention.
In FIG. 6, 201 (201a, b) is a celestial body to be measured such as a star, moon, earth, etc., 202 (202a, b) is an optical system having a function of condensing light from the celestial body 201 to be measured, 203 (203a, b) denotes a two-dimensional image sensor such as a CCD for acquiring an image collected by the optical system 202;
Reference numeral 04 (204a, b) denotes an A / D converter for converting an analog luminance signal of the two-dimensional image sensor 203 into a digital luminance signal, and 205 (205a, b) denotes the two-dimensional image sensor 203.
A synchronization circuit for synchronizing data transfer between the A / D converter 204 and the A / D converter 204, and 206 (206a, b) is an A / D converter 2
An image memory for storing the digital luminance signal of No. 04,
Reference numeral 207 (207a, b) denotes an address generation circuit for generating a storage address in the image memory 206, and 208 reads data from the image memory 206 to calculate the position of the celestial body 201 to be measured, or further determines the attitude of the satellite from this information. The star sensor dedicated processor 209 to be calculated is an attitude control processor that receives data from the star sensor dedicated processor. Here, the optical system 202 and the two-dimensional imaging device 2
03, the A / D converter 204, the synchronization circuit 205, the image memory 206, and the address generation circuit 207, there are a plurality of sets. FIG. 6 shows an example of two sets.

Next, the operation will be described. Optical system 202
The image of the celestial body 201 to be measured collected in step 2 is acquired by the two-dimensional image sensor 203. The two-dimensional image sensor 203 outputs the obtained image as an analog luminance signal. The analog luminance signal is converted into a digital luminance signal by the A / D converter 204 and stored in the image memory 206. As described above, the acquired data of the plurality of two-dimensional imaging elements 203 is stored in the respective memories 206. The star sensor dedicated processor 208 reads the data stored in the plurality of memories 206 and calculates the position of the celestial body 201 to be measured, or further calculates the attitude of the satellite from this information,
The data is sent to the attitude control processor 209 as data necessary for the attitude control of the satellite.

As described above, according to the present embodiment, the image signals obtained by the plurality of two-dimensional imaging elements 203 are stored in the memory 206 readable from one dedicated processor 208, and these image data are stored in the processor 206. By performing the processing in 208, the star sensor device and the entire artificial satellite can be reduced in size, weight, cost, and power consumption.

Embodiment 6 FIG. FIG. 7 is a block diagram showing a configuration of a star sensor according to Embodiment 6 of the present invention.
In FIG. 7, 201 (201a, b) is a celestial body to be measured such as a star, moon, earth, etc., 202 (202a, b) is an optical system having a function of condensing light from the celestial body 201 to be measured, 203 (203a, 203b) is a two-dimensional imaging device such as a CCD for acquiring an image collected by the optical system 202;
An A / D 204 (204a, b) converts an analog luminance signal of the two-dimensional image sensor 203 into a digital luminance signal.
The converter 205 (205a, 205b) is the two-dimensional image sensor 20
3 and a synchronization circuit for synchronizing data transfer between the A / D converter 204, 206 (206a, b) an image memory for storing the digital luminance signal of the A / D converter 204, and 207 (207a, b) is an address generation circuit for generating a storage address in the image memory 206. Reference numeral 209 denotes a processor for controlling the attitude of the satellite.
Is read out to calculate the position of the celestial body 201 to be measured, or a satellite attitude calculation unit that further calculates the attitude of the satellite from this information. Here, the optical system 202, the two-dimensional image sensor 203, the A / D converter 204, the synchronization circuit 2
05, image memory 206, and address generation circuit 207
There are a plurality of sets, but FIG. 7 shows a case of two sets as an example.

Next, the operation will be described. Optical system 202
The image of the celestial body 201 to be measured collected in step 2 is acquired by the two-dimensional image sensor 203. The two-dimensional image sensor 203 outputs the obtained image as an analog luminance signal. The analog luminance signal is converted into a digital luminance signal by the A / D converter 204 and stored in the image memory 206. As described above, the acquired data of the plurality of two-dimensional imaging elements 203 is stored in the respective memories 206. The attitude control processor 209 reads out the data stored in the plurality of memories 206 and calculates the position of the celestial body 201 to be measured.
Alternatively, the satellite attitude is calculated from this information and used as data necessary for satellite attitude control.

As described above, according to the present embodiment, the image signals acquired by the plurality of two-dimensional image sensors 203 can be read from the satellite attitude control processor 209 by the memory 20.
6 and the image data is processed by the attitude control processor 206, so that the star sensor device and the entire artificial satellite can be reduced in size, weight, cost, and power consumption. There is. Further, information available to the attitude control processor 209, such as the driving status of the control actuator and the orbit information of the artificial satellite, can be efficiently used for the satellite attitude calculation processing using the star sensor. Has the effect of improving the accuracy of

Embodiment 7 FIG. 8 is a block diagram showing a configuration of a star sensor according to Embodiment 7 of the present invention.
In FIG. 8, reference numeral 210 (210a to 210c) denotes a part of the star sensor according to any of the above embodiments, which is a star sensor head that inputs star light, converts the light into digital signals, and outputs the digital signals. is there. 6 and 7, the star sensor head unit 210 includes the optical system 202 and the two-dimensional imaging device 2.
03, an A / D converter 204, a synchronization circuit 205, and an address generation circuit 207. 211 (211a-c)
Is a star image processing unit that is connected to each star sensor head unit 210 in one-to-one correspondence, stores the output of the star sensor head unit 210, and performs image processing. 212 (212a to 212c) denotes the processing of the star image processing unit 211. Attitude determining units 213 (213a to 213c) for calculating the attitude of the satellite from the result include a plurality of attitude determining units 2
This is a normal system selection unit that removes erroneous data caused by a failure or the like from the 12 processing results and selects a normal processing result. Here, the star image processing unit 211 is surrounded by a broken line.
And the attitude determination unit 212 represent processing by one processor.

Next, the operation will be described. The star sensor according to the present embodiment has three units (units A, B, and C) including a star sensor head unit 210, a star image processing unit 211, and an attitude determination unit 212. The output of the star sensor head unit 210 is input to the star image processing unit 211 in the same unit, and calculates the pixel coordinates of the celestial object to be measured. The processing result of the star image processing unit 211 is input to all or a plurality of the attitude determining units 212 in the own and other units, and the acquired data is shared. The attitude determination unit 212 at the subsequent stage that shares these data executes the same processing to calculate the attitude of the satellite. The outputs of these attitude determination units 212 are input to the normal system selection unit 213. If the posture determination units 212 of all the units perform the normal processing, these outputs all match. For example,
Only the attitude determining unit 212a of the unit A fails and the attitude determining unit 212b of the unit B and the attitude determining unit 2 of the unit C fail.
If 12c is normal, the posture determination unit 212 of the unit B
Only b and the output of the attitude determination unit 212c of the unit C match each other. Therefore, the normal system selection unit 213 can obtain the processing result of the posture determination unit 212 that is performing normal processing by performing majority processing on the three processing results of the posture determination unit 212 that is input. 213 output. In addition, when two units have independent failures at the same time, the posture determination units 212 of the three units output three different outputs. The normal system selection unit 213 cannot obtain a normal output by the majority decision processing, but can determine that a failure has occurred, and can output an output indicating the determination result. Further, in this example, the time of failure is shown, but the same effect can be obtained for a temporary failure such as a temporary bit inversion.

As described above, according to the present embodiment, the star sensor head 210 and the star sensor head 2
A plurality of units each including a star image processing unit 211 for calculating the pixel coordinates of a star from the ten image data and an attitude determination unit 212 for calculating the attitude of the artificial satellite from the processing result are provided. The output of the processing unit 211 is input to all or a plurality of the posture determination units 212 in the own and other units, and the acquired data is shared. In this way, the post-stage attitude determination unit 2 that shares these data
12, since the same processing can be performed, the outputs of these attitude determination units 212 can be compared, and the configuration is such that the normal attitude determination unit 212 can determine the normal processing. Therefore, the effect of improving fault tolerance is improved. There is. In the above description, the star sensor head unit 210 and the star image processing unit 21
Although the case where 1 corresponds to 1 to 1 has been shown, the multiplexer 122 as described in the third embodiment is provided between the star sensor head unit 210 and the star image processing unit 211.
It is also possible to adopt a configuration in which three of the outputs of the zero star sensor head unit 210 are input to the three star image processing units 211. This is the same in the following eighth and ninth embodiments.

Embodiment 8 FIG. FIG. 9 is a block diagram showing a configuration of a satellite attitude control device according to Embodiment 8 of the present invention. In FIG. 9, reference numeral 210 (210a to 210c) denotes a part of the star sensor according to any of the above-described embodiments, which is a star sensor head for inputting star light, converting the light into digital signals, and outputting the digital signals. is there. 6 and 7, the star sensor head unit 210 includes an optical system 202, a two-dimensional image sensor 203, an A / D converter 204, and a synchronization circuit 20.
5 and an address generation circuit 207. 211 (2
11a-c) are one-to-one with each star sensor head section 210
, A star image processing unit 212 (212a) that stores the output of the star sensor head unit 210 and performs image processing.
-C) are attitude determination units that calculate the attitude of the satellite from the processing result of the star image processing unit 211, and 214 (214a to c) are connected to each attitude determination unit 212 in one-to-one correspondence, and the attitude is determined based on the processing results. The control operation unit 213 (213a to 213c) that generates a drive command signal to the control actuator 215 eliminates erroneous data caused by a failure or the like from the processing results of the plurality of control operation units 214, and obtains a normal processing result. Is a normal system selection unit for selecting. A control actuator 215 receives a drive command from the normal system selection unit 213. Here, the star image processing unit 211, the attitude determination unit 212, and the control calculation unit 214 represent processing by one processor as surrounded by a broken line.

Next, the operation will be described. The attitude control device for an artificial satellite according to the present embodiment has three units (units A, B, and C) each including a star sensor head unit 210, a star image processing unit 211, an attitude determination unit 212, and a control calculation unit 214. have. Star sensor head 210
Is input to the star image processing unit 211, and the pixel coordinates of the celestial object to be measured are calculated. The processing result of the star image processing unit 211 is used by all of the attitude determination units 212 in the own and other units.
Alternatively, input is made to a plurality of users to share the acquired data. Post-stage attitude determination unit 21 that shares these data
In step 2, the same processing is executed to calculate the attitude of the satellite.
The outputs of these attitude determination units 212 are input to the control calculation unit 214 to generate drive command signals to the attitude control actuator. The outputs of these control calculation units 214 are input to the normal system selection unit 213. If the attitude determination unit 212 and the control calculation unit 214 of all units perform normal processing,
These outputs all match. For example, unit A
Only the attitude determination unit 212a or the control calculation unit 214a of the unit B fails, and the attitude determination unit 212b of the unit B and the control calculation unit 2
14b, the attitude determination unit 212c of the unit C and the control calculation unit 214c are normal, the control calculation unit 21 of the unit B
4b and the output of the control operation unit 214c of the unit C only match each other. Therefore, the normal system selection unit 213 can obtain the processing result of the control operation unit 214 that performs normal processing by performing majority processing on the three processing results of the control operation unit 214 input thereto. A command is sent to the control actuator 215 as the output of 213. When two units have independent failures at the same time, the control calculation units 214 of the three units output three different outputs. The normal system selection unit 213 cannot obtain a normal output by the majority decision processing, but can determine that a failure has occurred, and can output an output indicating the determination result. Further, in this example, the time of failure is shown, but the same effect can be obtained for a temporary failure such as a temporary bit inversion.

As described above, according to the present embodiment, the star sensor head 210 and the star sensor head 2
A star image processing unit 211 that calculates the pixel coordinates of a star from the ten image data, an attitude determination unit 212 that calculates the attitude of the artificial satellite from this processing result, and a drive command signal to an attitude control actuator is generated from the attitude information. Control operation unit 214
, And outputs the outputs of the plurality of star image processing units 214 to all or a plurality of the attitude determination units 212 in the other units and obtains the obtained data. Let them share. In this way, the same processing can be performed by the attitude determination unit 212 and the control calculation unit 214 at the subsequent stage that share these data.
Since the outputs of these control calculation units 214 can be compared with each other and the attitude determination unit 212 and the control calculation unit 214 whose processing is normal can be determined, there is an effect of improving fault tolerance.

Embodiment 9 FIG. FIG. 10 is a block diagram showing a configuration of a satellite attitude control device according to Embodiment 9 of the present invention. In FIG. 10, 210 (210a to 210c)
Is a part of the star sensor described in any of the above embodiments, and is a star sensor head unit that inputs star light, converts it into a digital signal, and outputs the digital signal. 6 and 7, the star sensor head unit 210 includes an optical system 202, a two-dimensional image sensor 203, an A / D converter 204, and a synchronization circuit 2.
05 and an address generation circuit 207. 211
(211a-c) are the star sensor heads 210 and 1
A star image processing unit 212 (21) that is connected in one-to-one correspondence, stores the output of the star sensor head unit 210, and performs image processing.
2a to 2c) are attitude determination units which are connected to the respective star image processing units 211 in one-to-one correspondence and calculate the attitude of the satellite from the processing results, and 214 (214a to c) are based on the processing results of the attitude determination unit 212. The control calculation unit 213 (213a to 213c) that generates a drive command signal to the attitude control actuator 215 eliminates erroneous data caused by a failure or the like from the processing results of the plurality of control calculation units 214 and performs normal processing. This is a normal system selection unit for selecting a result. 215 is a normal system selection unit 21
3 is a control actuator that receives a drive command from the control actuator 3.
Here, the star image processing unit 211, the attitude determination unit 212, and the control calculation unit 214 represent processing by one processor as surrounded by a broken line.

Next, the operation will be described. The artificial satellite attitude control apparatus according to the present embodiment has three units each including a star sensor head unit 210, a star image processing unit 211, an attitude determination unit 212, and a control calculation unit 214. The output of the star sensor head unit 210 is input to the star image processing unit 211, and calculates the pixel coordinates of the celestial body to be measured. The processing result of this star image processing unit 211 is
2 to calculate the attitude of the satellite. The processing result of the attitude determination unit 212 is input to all or a plurality of the control calculation units 214 in the own and other units to share the acquired data. The control operation unit 214 at the subsequent stage that shares these data executes the same processing to generate a drive command signal to the attitude control actuator.
The outputs of these control calculation units 214 are output to the normal system selection unit 213.
Is input to If the control operation units 214 of all units perform normal processing, these outputs all match.
For example, if only the control calculation unit 214a of the unit A fails and the control calculation unit 214b of the unit B and the control calculation unit 214c of the unit C are normal, the control calculation unit 214b of the unit B and the control calculation unit 214c of the unit C Only the outputs of Therefore, the normal system selection unit 21
3, the control operation unit 21 which performs normal processing by performing majority processing on the three processing results of the input control operation unit 214
4 can be obtained.
A command is sent to the control actuator 215 as the output of 13. When two units have independent failures at the same time, the control calculation units 214 of the three units output three different outputs. The normal system selection unit 213 cannot obtain a normal output by the majority decision processing, but can determine that a failure has occurred, and can output an output indicating the determination result. Further, in this example, the time of failure is shown, but the same effect can be obtained for a temporary failure such as a temporary bit inversion.

As described above, according to the present embodiment, the star sensor head 210 and the star sensor head 2
A star image processing unit 211 that calculates the pixel coordinates of a star from the ten image data, an attitude determination unit 212 that calculates the attitude of the artificial satellite from this processing result, and a drive command signal to an attitude control actuator is generated from the attitude information. Control operation unit 214
And a plurality of units composed of a plurality of units, and inputting the outputs of the plurality of posture determination units 212 to all or a plurality of control calculation units 214 in the other units to share acquired data. Let In this way, since the same processing can be performed in the subsequent control operation unit 214 sharing these data, the outputs of these control operation units 214 can be compared, and the control operation unit in which the processing is normal Since it is configured so that 214 can be determined, there is an effect of improving fault tolerance.

[0048]

As described above, according to the first aspect, an optical system for condensing the light of a star or the sun and a two-dimensional imaging device for converting the light condensed by the optical system into an electric signal are provided. An image input unit having a data processing device that processes a signal output by the two-dimensional image sensor.
An ND filter attached to the image input unit so that the position can be changed by a positioning device is provided. When sunlight reaches the two-dimensional imaging device through the optical system, the ND filter is used as the optical device. It is arranged on the optical path from the system to the two-dimensional image sensor and attenuates the amount of sunlight passing through the optical system so as to have an appropriate exposure amount of the two-dimensional image sensor. When only a star image is formed on the image sensor, the ND filter is removed from the optical path and the light condensed by the optical system is directly formed on the two-dimensional image sensor. An image of the sun is generated on the two-dimensional image sensor in an appropriate exposure state, and the direction of the sun with respect to the satellite can be detected. As a result, the attitude of the satellite can be measured. As a result, since the star sensor can be used as a substitute for the sun sensor, the sun sensor, which is usually indispensable for a satellite, is not required, and there is an effect that the cost of the satellite can be reduced.

According to the second aspect of the present invention, the image input unit is provided with a lens attached so that the position can be changed by a positioning device, and when the sunlight reaches the two-dimensional image pickup device through the optical system. , ND filter,
Since the lens is also disposed on the optical path from the optical system to the two-dimensional image pickup device, the viewing angle when measuring the direction of the sun can be increased.

According to the third aspect, an image having an optical system for condensing star light and a two-dimensional image pickup device for converting a star image condensed by this optical system into an electric signal and sequentially outputting it as luminance data In a star sensor including an input unit and a data processing device for processing luminance data, a low-pass filter whose luminance constant output by the two-dimensional imaging element is an input, and whose time constant is sufficiently longer than a measurement cycle of the star sensor. And an image memory for storing the output of the low-pass filter. Each time the two-dimensional image sensor outputs one piece of luminance data, the data of the corresponding image memory is subtracted from the luminance data. Since the data is input to the data processing device, accurate luminance of each pixel can be measured.

According to the fourth aspect of the present invention, there are provided an optical system for condensing star light and a two-dimensional image pickup device for converting a star image condensed by the optical system into an electric signal and sequentially outputting the electric signal as luminance data. A plurality of image input units, a multiplexer that receives outputs of all the image input units, selects some of the plurality of inputs and outputs the selected inputs, and an output that receives the output of the multiplexer and includes the image input unit. A processing device that calculates the attitude of the satellite, and an image input unit that estimates the star image obtained by each of the image input devices from the calculated attitude of the satellite and is expected to be able to measure the attitude of the satellite with the highest accuracy. An input image selecting unit for selecting and selecting an image input unit by outputting a command relating to the selection of the image input unit to the multiplexer. Improves, even if such sunlight as fall in the field of view of one of the image input unit predicts the incidence of sunlight, the sunlight can be stably measured by not using an image input unit that enters.

According to the fifth aspect, an image having an optical system for condensing star light and a two-dimensional image pickup device for converting a star image condensed by this optical system into an electric signal and sequentially outputting it as luminance data A plurality of input units are provided, at least one of which is an image input unit A attached to the satellite after the correct mounting attitude is adjusted with respect to the satellite, and the others are lower than the measurement accuracy of the star sensor. An image input unit B attached to the satellite with high accuracy; and a processing device for inputting images captured by the image input unit A and the image input unit B at the same time and calculating the attitude of the satellite. Calculating a difference between the attitudes of the satellites obtained using the respective outputs of the unit A and the image input unit B, and adding the difference to the output of the satellite attitude obtained using the output of the image input unit B; Then, the mounting posture of the image input unit B Since the satellite's attitude with corrected errors can be obtained, the adjustment of the mounting attitude when mounting the star sensor on the satellite structure is reduced, which can reduce the satellite development cost, and the mounting attitude shift due to impact at launch etc. This also has the effect that it becomes acceptable.

According to the sixth aspect, an optical system for condensing star light and a plurality of image input units each having a two-dimensional image sensor for converting a star image condensed by the optical system into an electric signal are provided. A plurality of memories for respectively storing the images output from the respective image input units, and a processor for processing the image data stored in the respective memories to calculate the attitude of the satellite on which the image input units are mounted, and And a satellite attitude calculation unit having one star sensor processor for sending the satellite attitude data to the plurality of image input units. The star attitude calculation process is performed by the one star sensor processor. Smaller, lighter, lower cost,
Low power consumption can be achieved.

According to the seventh aspect, an optical system for condensing star light and a plurality of image input units each having a two-dimensional image pickup device for converting a star image condensed by the optical system into an electric signal are provided. A plurality of memories respectively storing the images of the respective image input units, and one attitude control processor for processing the image data stored in the respective memories and calculating the attitude of the satellite equipped with the image input unit Since the satellite attitude calculation processing of the plurality of image input units is performed by the one satellite attitude control processor, the star sensor device and the entire artificial satellite can be reduced in size, weight, and cost. This has the effect of reducing power consumption. Further, information available to the attitude control processor, such as the driving status of the control actuator and the orbit information of the artificial satellite, can be efficiently used for the satellite attitude calculation processing using the star sensor. This has the effect of improving accuracy.

According to the eighth aspect of the present invention, there are provided an optical system for condensing star light and a two-dimensional image pickup device for converting a star image condensed by the optical system into an electric signal and sequentially outputting it as luminance data. A plurality of image input units, a plurality of star image processing units connected to each of the image input units and calculating the pixel coordinates of the star from the respective luminance data, and the image input unit based on the processing results of these star image processing units A plurality of attitude determination units that calculate the attitude of the satellite to be mounted, and input the output of each of the star image processing units to all or a plurality of the attitude determination units,
A normal system determination unit that compares the respective outputs obtained by performing the same processing in the plurality of posture determination units and selects a normal system output of the posture determination unit is provided, thereby improving fault tolerance. effective.

According to the ninth aspect of the present invention, there are provided an optical system for condensing star light and a two-dimensional image pickup device for converting a star image condensed by the optical system into an electric signal and sequentially outputting the electric signal as luminance data. A plurality of image input units, a plurality of star image processing units connected to each of the image input units and calculating the pixel coordinates of the star from the respective luminance data, and the image input unit based on the processing results of these star image processing units A plurality of attitude determination units for calculating the attitude of the onboard artificial satellite; and a plurality of attitude determination units connected in a one-to-one correspondence with each of the attitude determination units to generate a drive command signal to the attitude control actuator from the attitude information. And the output of each of the star image processing units is input to all or a plurality of the attitude determining units, and the plurality of attitude determining units and the control arithmetic units perform the same processing. Obtained Since a normal-determination unit for comparing an output of the respective control arithmetic unit selects the output of the normal system of the posture determination unit and the control arithmetic unit, the effect of improving the fault tolerance.

According to the tenth aspect, there are provided an optical system for condensing star light and a two-dimensional image pickup device for converting a star image condensed by the optical system into an electric signal and sequentially outputting the electric signal as luminance data. A plurality of image input units, a plurality of star image processing units connected to the image input units and calculating the pixel coordinates of the stars from the respective luminance data, and a one-to-one correspondence with the star image processing units. A plurality of attitude determination units that calculate the attitude of the satellite on which the image input unit is mounted from the processing results and a plurality of attitude determination units that generate drive command signals to the attitude control actuator from the attitude information of these attitude determination units; And the outputs of the attitude determining units are input to all or a plurality of the control arithmetic units, and the outputs obtained by performing the same processing in each of the plurality of control arithmetic units are compared. I Since a normal-judging unit for selecting the output of the normal system of the control computation unit, the effect of improving the fault tolerance.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a main part of a star sensor according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a star sensor according to a second embodiment of the present invention.

FIG. 3 is a flowchart illustrating a method of updating a dark output according to Embodiment 2 of the present invention;

FIG. 4 is a block diagram illustrating a star sensor according to a third embodiment of the present invention.

FIG. 5 is a block diagram illustrating a star sensor according to a fourth embodiment of the present invention.

FIG. 6 is a block diagram illustrating a star sensor according to a fifth embodiment of the present invention.

FIG. 7 is a block diagram illustrating a star sensor according to a sixth embodiment of the present invention.

FIG. 8 is a block diagram illustrating a star sensor according to a seventh embodiment of the present invention.

FIG. 9 is a block diagram illustrating an attitude control device for an artificial satellite according to an eighth embodiment of the present invention.

FIG. 10 is a block diagram illustrating an attitude control device for an artificial satellite according to a ninth embodiment of the present invention.

[Explanation of symbols]

Reference numeral 101: an image input unit, 101A: an image input unit in which the mounting posture is accurately adjusted, 101B: an image input unit in which the mounting posture is not accurately adjusted, 102, 20
2 optical system, 103 ND filter, 104 lens for expanding viewing angle, 105, 203 two-dimensional image sensor,
106 two-dimensional image sensor control circuit, 107 filter positioning mechanism, 110 A / D conversion unit, 111 subtraction unit, 112 image memory, 113 satellite attitude calculation unit, 114 dark output data update unit, 115 dark output storage unit, 121 Input image predictor, 122 multiplexer, 131 alignment error calculator,
132 alignment error correction unit, 201 celestial body to be measured, 204 A / D converter, 205 synchronization circuit, 206 image memory, 207 address generation circuit, 208 dedicated processor for star sensor, 209
Attitude control processor, 210 star sensor head unit, 211 star image processing unit, 212 attitude determination unit,
213 normal system selection unit, 214 control operation unit, 2
15 Control actuator.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI G01J 1/44 G01J 1/44 E

Claims (10)

[Claims] 1. An image input unit having an optical system for condensing light of a star or the sun, a two-dimensional image sensor for converting light condensed by the optical system into an electric signal, and an output device for the two-dimensional image sensor. A star sensor provided with a data processing device for processing a signal to be processed, wherein the image input unit is provided with an ND filter attached so that the position can be changed by a positioning device, and the two-dimensional imaging device receives sunlight through the optical system. When the light reaches the optical system, the ND filter is arranged on the optical path from the optical system to the two-dimensional image sensor, and the amount of sunlight passing through the optical system is appropriately exposed to the two-dimensional image sensor. In the case where only the star image is formed on the two-dimensional image sensor without sunlight, the ND filter is removed from the optical path and collected by the optical system. A star sensor, which forms an image of light directly on the two-dimensional image sensor. 2. The image input unit according to claim 1, further comprising a lens attached to the image input unit so that the position can be changed by a positioning device, wherein when the sunlight reaches the two-dimensional image sensor through an optical system, 2. The star sensor according to claim 1, wherein, in addition to the ND filter, the lens is disposed on an optical path from the optical system to the two-dimensional image sensor. 3. An image input unit having an optical system for condensing star light, a two-dimensional imaging device for converting a star image condensed by the optical system into an electric signal and sequentially outputting the electric signal as luminance data, A low-pass filter that receives the luminance data output by the two-dimensional image sensor and has a time constant that is sufficiently long as compared with the measurement cycle of the star sensor. And an image memory for storing an output. Each time the two-dimensional image sensor outputs one piece of luminance data, the data of the corresponding image memory is subtracted from the luminance data, and the result is input to the data processing device. A star sensor, characterized in that: 4. A plurality of image input units each having an optical system for condensing star light, and a two-dimensional image sensor for converting a star image condensed by the optical system into an electric signal and sequentially outputting the electric signal as luminance data. A multiplexer for inputting the outputs of all the image input units and selecting and outputting some of the plurality of inputs, and calculating the attitude of a satellite equipped with the image input units by inputting the outputs of the multiplexers A processing device and a star image obtained by each of the image input devices are estimated from the calculated attitude of the satellite, and an image input unit expected to be able to measure the attitude of the satellite with the highest accuracy is selected. A star sensor, comprising: an input image selecting unit that outputs a command regarding the selection of the image input unit and selects the image input unit. 5. An optical system for condensing star light and a plurality of image input units each having a two-dimensional image pickup device for converting a star image condensed by the optical system into an electric signal and sequentially outputting the electric signal as luminance data. At least one of them is an image input unit A mounted on the satellite after the correct mounting attitude is adjusted with respect to the satellite, and the other is mounted on the satellite with lower accuracy than the measurement accuracy of the star sensor. Image input unit B,
At the same time, there is provided a processing unit for inputting the images captured by the image input unit A and the image input unit B and calculating the attitude of the satellite, and using the respective outputs of the image input unit A and the image input unit B The difference between the obtained attitude of the satellite is obtained, and the difference is added to the output of the attitude of the satellite obtained using the output of the image input unit B, thereby correcting the error in the mounting attitude of the image input unit B. A star sensor characterized in that it can obtain the attitude of a satellite that has been set. 6. A plurality of image input units each having an optical system for condensing star light, a two-dimensional imaging device for converting a star image condensed by the optical system into an electric signal, and each of these image input units A plurality of memories each storing an image output by
A satellite attitude calculation unit having one star sensor processor that processes the image data stored in each of these memories to calculate the attitude of the satellite equipped with the image input unit and sends it to an attitude control processor. A star sensor, wherein the satellite attitude calculation processing of a plurality of image input units is performed by the one star sensor processor. 7. A plurality of image input units each having an optical system for condensing star light, a two-dimensional image pickup device for converting a star image condensed by the optical system into an electric signal, and each of these image input units And a plurality of memories for respectively storing images of the above, and a satellite attitude calculation unit comprising one attitude control processor for processing image data stored in each of the memories and calculating an attitude of a satellite equipped with the image input unit. Wherein the satellite attitude calculation processing of the plurality of image input units is performed by the one satellite attitude control processor. 8. A plurality of image input units each having an optical system for condensing star light and a two-dimensional image sensor for converting a star image condensed by the optical system into an electric signal and sequentially outputting the electric signal as luminance data. A plurality of star image processing units connected to each of the image input units to calculate the pixel coordinates of the star from the respective luminance data, and the attitude of the satellite on which the image input unit is mounted based on the processing results of these star image processing units Are obtained by inputting the output of each of the star image processing units to all or a plurality of the plurality of attitude determination units, and performing the same processing in the plurality of attitude determination units. A star sensor comprising: a normal system determination unit that compares each output and selects a normal system output of the posture determination unit. 9. A plurality of image input units each including an optical system for condensing star light, and a two-dimensional image sensor for converting a star image condensed by the optical system into an electric signal and sequentially outputting the electric signal as luminance data. A plurality of star image processing units connected to each of the image input units and calculating the pixel coordinates of the star from the respective luminance data, and a satellite equipped with the image input unit based on the processing results of these star image processing units. A plurality of posture determination units for calculating the posture, a plurality of control calculation units connected in a one-to-one correspondence with each of the posture determination units, and each of which generates a drive command signal to the posture control actuator from the posture information;
The output of each of the star image processing units is input to all or a plurality of the plurality of attitude determination units, and the plurality of control units obtained by performing the same processing in each of the plurality of attitude determination units and the control calculation units. An attitude control device for an artificial satellite, comprising: an attitude determination section that compares outputs of an arithmetic section and a normal system determination section that selects a normal system output of the control arithmetic section. 10. A plurality of image input units each having an optical system for condensing star light, and a two-dimensional image pickup device for converting a star image condensed by the optical system into an electric signal and sequentially outputting the electric signal as luminance data. A plurality of star image processing units connected to each of the image input units to calculate the pixel coordinates of the star from the respective luminance data, and connected in a one-to-one correspondence with each of the star image processing units, A plurality of attitude determination units that calculate the attitude of the satellite on which the image input unit is mounted, and a plurality of control calculation units that respectively generate drive command signals to the attitude control actuator from the attitude information of these attitude determination units, The output of each of the attitude determining units is input to all or a plurality of the control arithmetic units, and the outputs obtained by performing the same processing in each of the plurality of control arithmetic units are compared to each other. Positive An attitude control device for an artificial satellite, comprising: a normal system determination unit that selects an output of a normal system.