JPH0626857A - Solar sensor for z-axis - Google Patents

Abstract

PURPOSE: To make it possible to measure by only one solar sensor and one detector array by forming a light incident slit in a rectangular shape, and detecting and calculating the incident angle of the solar light by the illuminated detector of the one half of the array. CONSTITUTION: Light incident slits S arranged at a predetermined interval are formed in a rectangular shape or at a predetermined angle on the detector array of a measuring range flat surface. The array is formed of photodiodes or CCD. The illuminated states of the individual detectors are read at the output ends of read electronic circuit, and an evaluation electronic circuit calculates the incident angles α, β of the light from the number of the illuminated detectors. The angles α, β are the angles of the solar vectors to the Z axis when the vectors are projected to the two flat surfaces of XZ surface and YX surface. The angle α is detected by the illuminated detector (e.g. detectors 1 to 2000) if the one half of the array, and the angle β is detected by he illuminated detector (e.g. 2001 to 4000) of the other half of the array at the output end of the read electronic circuit, and calculated by the folding evaluation electronic circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention uses an incident point at which sunlight passing through a slit is incident on a detector array composed of a large number of individual sensors in order to determine an incident angle, and the satellite attitude is determined. It relates to a sun sensor for the Z axis that is for detecting.

[0002]

2. Description of the Prior Art Solar sensors for the Z-axis, which are used to measure the attitude of satellites, are known per se. Reference "Spacecraft
Attitude Determination and Control "by James R. W
The basis for satellite attitude measurement is known from ertz, D. Reidel Publishing Company, 1985. It proposes, in particular, the position of the sun relative to the coordinate system of the satellite. Such a posture measurement with a sun sensor is illustrated in simplified form in the schematic diagram of FIG. here,
“S” represents the sun vector, and α is XZ of the sun vector.
The plane component is projected on the Z axis, and β is the YZ plane component of the sun vector projected on the Z axis. To measure the attitude, for these angles α and β, the prior art requires the use of two sun sensors arranged at an angle of 90 ° to each other.

In these known sun sensors, the applicant has determined that the sunlight passing through the slit is used to obtain the incident angle.
The point of incidence on a detector array with 2,048 adjacent detectors was used. To be able to measure both angles α and β, two sensors or sensor heads need to be placed at 90 °, as already explained. Also associated with this are two detector arrays with associated readout electronics,
Furthermore, an electronic box of the attitude control system is also related.

[0004]

SUMMARY OF THE INVENTION The object of the present invention is to provide angles α and β with only one sun sensor and one detector array.
The object is to provide a sun sensor of the kind mentioned at the outset, which is capable of measuring

[0005]

SUMMARY OF THE INVENTION According to the invention, the above-mentioned object is achieved in a sun sensor of the type mentioned at the outset in which the light of a diaphragm arranged at regular intervals on a detector array in the measuring range plane. An illuminated detector in which the incident slit S is formed in a rectangular shape or a constant angle, and the incident angle α of sunlight is one half of the detector array (for example, detectors 1 to 2,000).
At the same time the incident angle β is the other half of the detector array illuminated detectors (eg detectors 2,001 to 4,000)
Are respectively detected at the output ends of the reading electronics and calculated by the subsequent evaluation electronics.

Other advantageous configurations according to the invention are described in the dependent claims.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail based on the embodiments schematically shown in the drawings. The general idea of the present invention is that the angles α and β can be measured with only one sun sensor and one detector array, due to the proper design of the light entrance slits and the arrangement of the detector arrays, which has been conventionally practiced. It is possible to maintain the measurement principle. That is, the spatial position or the incident point on the surface arranged at the interval "a" of the light incident through the slit "S" is used for the measurement of the incident angle.

In order to determine the position of the incident light, photoelectric detectors linearly arranged at regular intervals are used as in the conventional case. Such a device can be used in various embodiments depending on the number of detectors and the operating principle. The voltages of all detectors are read at periodic time intervals to determine the illuminated detectors. This reading is performed continuously. In other words, the time-sequential voltage of the detectors 1 to n, which is proportional to the light incident on the corresponding detector, is output to the output terminal of the reading electronic circuit of the detector array.

Such a detector array is composed of a photodiode and a CCD. This example assumes a detector array of 4,000 individual detectors. The illumination state of each numbered individual detector can be read at the output of the reading electronics. Subsequent evaluation electronics calculate the angle of incidence of the light from the number of illuminated detectors.

As can be understood from FIG. 2, the entrance slit S of the diaphragm is formed in a rectangular shape. To be optimal
Other angles may be used, as the case may be. If the light is incident exactly vertically (the sun vector is then perpendicular to the sensor plane (α = 0 °, β = 0 °)) the slit image illuminates the detectors numbered 1,000 and 3,000. . If the sun rays enter at other angles, this will result in an image movement of the slit in the image plane. In the effective measurement range, that is, in the moving range of the image formation of the slit on the image formation plane, the incident angle α is from 1 to 1.
Obtained from detectors illuminated up to 2,000,
The incident angle β can be obtained from the detectors illuminated in the range of numbers 2,001 to 4,000. The maximum measurable angle final value and the angle of the intermediate position (where the detector 1,000
And 3,000 illuminated) is given by the geometry of the entrance slit (space, lateral offset) with respect to the image plane and can be adjusted by design techniques. Advantageously, the detector array and its support and the read-out electronics and the evaluation circuit are arranged in a common case.

[0011]

As described above, the sun sensor according to the present invention can measure the angles α and β with only one sun sensor and one detector array.

[Brief description of drawings]

FIG. 1 is a schematic view of measuring a posture with a conventional sun sensor.

FIG. 2 is a perspective view showing a configuration of an embodiment of a sun sensor for simultaneously measuring angles α and β.

Claims (4)

[Claims] 1. A method for detecting the attitude of a satellite using the point of incidence of sunlight through a slit on a detector array consisting of a number of individual sensors to determine the angle of incidence. In the axial sun sensor, the light entrance slits S of a diaphragm arranged at regular intervals are formed on the detector array in the plane of the measurement range in a rectangular shape or at a constant angle, and the incident angle α of sunlight is the detector. With an illuminated detector that is one half of the array (e.g. detectors 1 to 2,000), and at the same time with an illuminated detector whose incident angle β is the other half of the detector array (e.g. detectors 2,001 to 4,000). A sun sensor, which is detected at each output end of a reading electronic circuit and calculated by a subsequent evaluation electronic circuit. 2. The maximum final value of the measurable angle and the angle of the intermediate position (the sun is perpendicular to the slit) are obtained from the geometrical arrangement of the distance (a) between the entrance slit and the image plane and the lateral shift. The solar sensor according to claim 1, wherein: 3. The sun sensor according to claim 1, wherein the distance (a) with respect to the image plane and the lateral displacement are adjustable. 4. The detector array according to claim 1, wherein the detector array, together with its support, cables and read-out electronics and evaluation electronics, are arranged in a common case. The sun sensor described.