JPH06100473B2 - Spacecraft attitude position determination device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a spacecraft attitude / position determination device, and more particularly to a spacecraft attitude / position determination device.
Small and lightweight spacecraft attitude suitable for mounting on a spacecraft
The present invention relates to a position determining device.

[Background of the Invention]

It is necessary to mount a spacecraft such as a space shuttle equipped with a position determination position for determining the position of the spacecraft in the inertial space and a position determination device for determining the position of the spacecraft. On the other hand,
The smaller the mass of the spacecraft, the less fuel it needs to launch, so it is desired to be lightweight, and because the mounting space is limited, it is hoped that the spacecraft will be downsized. . Therefore, it is desirable to develop a device having both a posture determination function and a position determination function, but this point has not been considered in the past.

Incidentally, as a device relating to the attitude determination device, Japanese Patent Laid-Open No.
No. 300 and JP-A No. 57-26100. Further, as a document regarding the attitude determination by the star sensor, for example, “Star fixation method in an artificial satellite attitude determination system using a star sensor” (28th Space Science and Technology Federation Lecture Meeting-198
4), Auto nomous Star Sensing And Attitude Estim
ation (John.L.Junkins, Thomas.E.Strikwerda 1979).

[Object of the Invention]

An object of the present invention is to provide a spacecraft attitude / position determination device that can be used for both attitude determination and position determination of a spacecraft.

[Outline of Invention]

When a spacecraft flies, if the directions and positions of at least two planets are known, the position of the spacecraft can be determined from the principle of triangulation. The attitude of the spacecraft can be determined if the position of the star is known.

Therefore, in the present invention, the position data of the stars and planets are stored in memory respectively, and the attitude and position of the spacecraft are determined from the position signals of the stars and planets detected by the star sensor and the data stored in the memory. It is configured to be operated by a microcomputer.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a hardware configuration diagram of the spacecraft attitude position determination device,
FIG. 2 is a block diagram of this embodiment, FIG. 3 is a flow chart of the position determining program, and FIG. 4 is an explanatory diagram of the position determining program.

In FIG. 1, 1 is a spacecraft, 2a and 2b are star sensors,
3 is a microcomputer. Star sensors 2a and 2b are connected to the microcomputer 3. The star sensors 2a and 2b use, for example, a two-dimensional solid-state image pickup device such as a CCD and a built-in microprocessor, and emit light from a star or planet within the field of view, that is, the light-receiving surface of the solid-state image pickup device. It is converted into a signal and sent to the microcomputer 3. The field of view of the star sensors 2a, 2b is about 1
Since it is 0 ° × 10 °, it is possible to capture the target star in the visual field even if the directions of the star sensors 2a and 2b are determined with rough accuracy.

A plurality of star sensors 2a, 2b are fixed to one spacecraft 1 in different directions (two in this embodiment), and the star sensors 2a, 2b are from a star of a certain grade or higher, for example, a 6-star or higher star in a certain visual field range. Light is detected by a built-in solid-state image sensor, the direction of light from the star, that is, the direction of the star is detected, and the direction is displayed and output as two pieces of angle information or an amount corresponding thereto. Further, the microcomputer 3 processes the data from the star sensors 2a and 2b.

In FIG. 2, the microcomputer 3 is a ROM, RA storing a posture determination program 6 and a position determination program 8.
The memory 5 consisting of M, the microprocessor 4 that performs processing such as calculation according to the programs and data stored in the memory 5, the memory ROM 7 storing the position data of each star, and the position data of each planet Built-in memory ROM 9 and stored.

Here, the ROM7 has a recording capacity of, for example, about 200 kbits, and data regarding the position on the celestial sphere (shown by two angles of right ascension and declination) and the magnitude of stars in the entire sky that are at least 6th magnitude stars. And are stored. The ROM 9 has a recording capacity of, for example, about 16 kbits, and stores data on orbital 6 elements of 9 planets and perturbation terms.

Next, the position determining program of the spacecraft 1 will be described.

Referring to FIG. 3, first, in step 11, the spacecraft 1 is moved so that the planet and the planets around it are within the field of view of the star sensor.
Change the posture of. The direction in which the planets and stars enter the field of view is obtained from the flight process up to that point and information from other sensors, and the direction of the spacecraft 1, that is, the attitude is determined by the star sensor attitude determination system before the attitude is changed. .

In the conventional attitude determination system using a star sensor, the microcomputer 3 calculates the angle of separation between stars based on the angle information of a plurality of stars output by the star sensors 2a and 2b according to the attitude determination program 6 and is closest to this angle of separation. Find a star pair that forms an angle of departure from the star position data, or the detected star corresponds to which star on the star position data based on its magnitude and information from other equipment installed on the spacecraft 1. The star sensor 2a, 2b and the angle information output from the star sensor 2a, 2b and the two angles of RA and declination indicating the position on the celestial sphere of one of the detected stars.
Processing for determining the direction of b, and thus the direction of the spacecraft 1 with the star sensors 2a, 2b fixed (step 1
1).

In the present invention, as shown in FIG. 4, the positions 23 and 24 on the celestial sphere are newly determined from the two angles of RA and declination.
To decide. This is obtained by identifying a star in the same field of view as the planet and detecting the angle of departure from it with the star sensors 2a, 2b. Alternatively, it can be obtained from the state before the spacecraft 1 changes its attitude, that is, the attitude angle with respect to the inertial coordinates, the attitude change angle measured by a gyro and the angles detected by the star sensors 2a and 2b (step 12). ).

At this time, the attitude of the spacecraft 1 with respect to the inertial space after the attitude change is also obtained (step 13).

Next, the direction of the planet in the inertial space is obtained from the attitude of the spacecraft 1 obtained in step 13 and the position signal of the planet detected previously (step 14).

The above steps 11 to 14 are repeated to find the directions of the two planets in the inertial space (step 15).

Next, in step 16 of FIG. 3 (b), step 12
The position of the planet at the time when the planet position signal was detected by
Obtained from the planet position data in ROM (step 16).

Next, the microcomputer 3 follows the position determination program 8 and, based on the time information from the clock or the like mounted on the spacecraft 1, first, the planets 21, 21 moving momentarily shown in FIG.
Calculate the position of the solar system at fixed (inertial) coordinates 22. The operation and prediction of planets have been investigated in more detail than before. Furthermore, from the predicted positional relationship between the spacecraft 1 and the planets, the positions 23 and 24 of the planets 20 and 21 projected on the celestial sphere can be accurately captured by the planets within the field of view of the star sensors 2a and 2b. Predict and identify planets in the field of view. The position of the spacecraft 1 is predicted by orbital calculation from the orbital determination performed at the time of launch or thereafter. Then, from the data obtained in step 16 of the two planets 20 and 21 and the direction obtained in step 14, the direction in which the spacecraft 1 can be seen from the planets 20 and 21, that is, the angle, is calculated in reverse. Since the positions of the planets 20 and 21 in the inertial space have been calculated, the lines 25 and 26 are extended from the multiple fixed planets in the direction in which the spacecraft 1 can be seen, and the intersections are calculated to calculate the principle of triangulation. To determine the position of the spacecraft 1 at the intersection (step 17). This is the end of the execution of the program shown in FIG.

〔The invention's effect〕

As described above, according to the present invention, it is possible to determine the attitude and the position of the spacecraft with one device, and it is possible to achieve the size and weight reduction of the device.

[Brief description of drawings]

FIG. 1 is a hardware configuration diagram of a spacecraft attitude position determination device according to an embodiment of the present invention, FIG. 2 is a block configuration diagram of the device shown in FIG. 1, and FIG. 3 is a microcomputer shown in FIG. FIG. 4 is a flowchart of the posture position determining program executed in FIG. 4, and FIG. 4 is an explanatory diagram of the position determining program. 1 ... Spacecraft, 2a, 2b ... Star sensor, 3 ... Microcomputer, 4 ... Microprocessor, 5 ... Memory, 6 ... Attitude determination program, 7,9 ... Memory, 8
...... Positioning program, 11,12,13,14,15,16 …… Flowchart steps, 20,21 …… Planet, 22 …… Fixed coordinates of the solar system, 23,24 …… Planet projected on the celestial sphere Position, 2
5,26 …… Line.

Claims (1)

[Claims] 1. A built-in image sensor detects light from a star of a certain grade or higher in an arbitrary visual field range, the direction of the star is detected by the detected light, and the direction is output as two angle information. The multiple star sensors fixed in the spacecraft in different directions to be displayed and the positions on the celestial sphere of stars of a certain grade or higher in the entire sky or a part of it are shown at two angles, RA and Decl. Calculate the angle of separation between the stars from the stellar position data shown, and the angle information of a plurality of stars output by the star sensor, and find the set of stars with the closest separation angle from the stellar position data, or Detected stars, identify which star on the star position data from the magnitude and information from other equipment mounted on the spacecraft, and detect the angle information output by the star sensor, One of the stars Space consisting of a microcomputer with a program that determines the direction of the star sensor, and hence the direction of the spacecraft to which the star sensor is fixed, from the two angles, RA and declination, which indicate the position on the celestial sphere. In the ship attitude position determination device, (i) a program that calculates the position of the planet that moves from moment to moment in the fixed coordinates of the solar system based on the time information from a clock mounted on the spacecraft, and a memory that records the calendar data of each planet. And (ii) after determining the direction of the spacecraft by the above method, in advance,
The position on the celestial sphere is predicted with the accuracy that the planet can complement within the field of view of the star sensor from the almost predicted position relationship between the spacecraft and the planet, and (iii) the attitude of the spacecraft is changed one or more times. By determining the position on these celestial spheres by placing multiple planets in the field of view of the star sensor, (iv) calculating the direction in which the spacecraft can be seen from these planets in reverse, and The position is calculated, and (v) a line is extended from a plurality of fixed planets in the direction in which the spacecraft can be seen, and the intersection is calculated to determine the position of the spacecraft at the intersection.
Spacecraft attitude position determination device.