KR100231821B1 - Digital solar sensor - Google Patents

Abstract

The present invention relates to a digital solar sensor for measuring the incident angle of sunlight. The light receiving unit for receiving light through the slit formed on the upper surface of the glass plate, the pattern provided with a transparent window of a predetermined size are arranged in parallel on the bottom surface of the glass plate, the pattern corresponding to the bit of the gray code is the viewing angle range of the slit Is divided into a plurality of predetermined equal angles, and the floodlights are alternately arranged in a position area on the bottom surface of the glass plate corresponding to the optical path incident into each division angle, so that the division angles of the slits are different in each pattern. By selectively transmitting sunlight incident at a predetermined angle with respect to the optical axis, the gray code pattern portion providing the on / off information of the bits, the sunlight rays passing through the gray code pattern portion are received and converted into an electrical signal An electron for calculating and displaying the incident angle from the photoelectric conversion unit and the electrical signal It consists of a circuit part, and the measurement resolution and measurement precision of the incidence angle of the sun are improved.

Description

Digital solar sensor

The present invention relates to a digital solar sensor for measuring the incident angle of sunlight.

The solar sensor is one of the sensors included in the attitude control system of the satellite, and is used to determine the attitude of the satellite using sunlight. That is, the solar sensor is used to determine the azimuth angle between the sun and the satellite body by determining the incident angle of the sunlight rays incident to the direction perpendicular to the light receiving surface of the solar sensor attached to the satellite body.

In the manufacture of such solar sensor, considerations should be given to the simple structure, light weight, small size, no deterioration of material after radiation of particle radiation in space, and after UV radiation. The transmittance should not be reduced. In addition, since the solar sensor is mounted on the surface of the satellite, its characteristics should not be changed in a space environment with a large temperature difference, and the influence of the reflected light of the earth should be considered.

Conventional solar sensors use analog solar sensors to measure the incident angle of sunlight.

1A and 1B illustrate a conventional analog solar sensor for explaining a method for measuring an angle of incidence of sunlight on a satellite.

Referring to (a) and (b) of FIG. 1, an analog solar sensor will briefly describe a method of measuring an incident angle of sunlight on a satellite.

The photodetector 2 is configured to detect the sunlight rays incident on the light receiving surface, and measures the change in the amount of light incident on the light receiving surface according to the angle of incidence and measures the angle of incidence from this value.

In FIG. 1A, the incident light amount of the sunlight is controlled by a mask 1 that shields the light so that the incident angle of the sunlight is easily measured, and the incident light amount is detected as the photodetector 2. In FIG. 1 (b), the photodetector 3 is divided into four and configured to detect the amount of light according to the incident angle of the sunlight on each of the divided planes a, b, c, d. When the sunlight is incident perpendicularly to the light receiving surface, the amount of light of the sunlight detected on each of the divided light receiving surfaces a, b, c, and d is equal, and when the sunlight is incident at a predetermined angle, the divided light receiving surface ( The amount of light detected in each of a, b, c and d is different. Therefore, the change in the incident angle can be measured by changing the amount of light of the sunlight detected from each of the divided light receiving surfaces a, b, c, and d. Incident angle is calculated by a computer with the light quantity signal detected from such a photodetector.

Analog solar sensors of the illustrated method are simple to manufacture because they measure the angle of incidence of sunlight from the amount of incident light of the sunlight incident on the photodetector, but has several problems as follows.

First, each element of the photodetector is inconsistent with each other in sensitivity characteristics and deterioration characteristics due to temperature change.

Second, measurement errors are easily caused by the noise source outside the light reflected from the earth.

Also, because the sun is close to the satellite, it cannot be seen as a point source, but as a circle with a viewing angle of about 0.52 degrees to the satellite. Therefore, in the analog solar sensor whose resolution is determined by the sensitivity characteristic of the photodetector, the resolution of the angle is usually limited to the range of 1 degree.

The present invention was devised to solve the above problems, and an object thereof is to provide a digital solar sensor having improved incident angle resolution of sunlight.

1 (a) and (b) are diagrams for explaining a conventional method for measuring the incident angle of sunlight.

Figure 2 is a partially exploded perspective view for explaining the operation of the digital solar sensor according to the present invention.

3 illustrates a configuration of the gray code pattern unit of FIG. 2.

4 is a block diagram of an electronic circuit unit.

* Explanation of symbols for major symbols in the drawings

1: mask 2, 3: photodetector

4 cylinder lens 5 slit

6: glass plate 7: gray cord pattern part

11: automatic threshold adjustment bit part 12: sign bit part

13: Outline Bit Section 14: Fine Bit Section

30: photoelectric conversion unit 31: solar cell

50: electronic circuit unit 51: field processing unit

52, 53, 62, 63: amplifier 60: outline bit calculator

61 switching means 64 comparator

65: gray code conversion unit 66: comparison unit

70: fine bit calculation unit 71: phase control unit

72: DC control means 73: band pass filter (BPF)

74: square wave conversion unit 75: gate adjustment unit

76: binary conversion unit 80: buffer

90: indicator 100: control unit

In order to achieve the above object, in the digital solar sensor according to the present invention, a cylinder lens is installed on an upper surface of a glass plate having a uniform thickness, and a slit having a uniform width along the longitudinal axis of the cylinder lens has an upper surface and a cylinder of the glass plate. A light receiving unit formed between the lenses; A flood control panel is provided on a bottom surface of the glass plate in which a plurality of patterns having one or more lines arranged in a line with a predetermined size of a transparent window are provided on the bottom surface of the glass plate, and the pattern corresponding to a bit of gray code defines a viewing angle range of the slit. The light-transmitting window is alternately arranged in a location area on the bottom surface of the glass plate corresponding to the optical path incident into each division angle by dividing into multiples at equal angles, so that the pattern angles are different from each other in the optical axis of the slit. A gray code pattern unit which selectively transmits sunlight incident on a predetermined angle with respect to the bit, thereby providing information on / off of the bits; A photoelectric conversion unit disposed to correspond to each of the patterns, the photoelectric conversion unit receiving the solar light incident through the light transmission window of the pattern and converting the received sunlight into an electrical signal; And an electronic circuit unit for calculating and displaying the incident angle from the electrical signal.

The gray code pattern unit may include a sine bit unit in which patterns are formed to determine an orientation of the sunlight; A gray code part in which patterns are formed to provide the incident angle information; And an automatic threshold adjustment bit part in which a pattern is formed to provide a signal as a reference for determining on / off of sunlight passing through the light transmission window of the gray code part pattern. An approximate bit section consisting of six patterns each having an equal dividing angle of 64 degrees, 32 degrees, 16 degrees, 8 degrees, 4 degrees, and 2 degrees with respect to the optical axis; And the first fine pattern having the equal dividing angle of about 1 degree with respect to the optical axis, and the even dividing angle being 1 degree with respect to the light transmission window arrangement of the first fine pattern. And a fine bit portion having a second fine pattern, a third fine pattern, and a fourth fine pattern, the pattern being formed to process the one degree range of the one fine pattern by 0.25 degrees.

Hereinafter, a digital solar sensor according to the present invention will be described in detail with reference to the accompanying drawings.

First, the angle of incidence measurement method will be described with reference to FIG.

The digital solar sensor is roughly divided into a light receiving portion, a gray code pattern portion 7, a photoelectric conversion portion 30, and an electronic circuit portion 50.

First, the method of calculating the incident angle of sunlight is briefly described.

When sunlight is incident on the gray code pattern portion 7 through the slit 5 at an angle of θ with respect to the optical axis, the output of the solar cell 31, which is an optoelectronic device provided at the bottom of the pattern, is turned on / off depending on the presence or absence of incident light. It is output as an electrical signal corresponding to and the information of the incident angle is processed by reading the gray code value represented by the combination of these signals.

Sunlight incident at a predetermined angle through the slit 5 passes through a position corresponding to the angle of incidence on the bottom surface of the glass plate 6 about the optical axis of the slit 5. The angle of incidence can be obtained using the thickness of. Accordingly, the gray code pattern portion 7 capable of processing the information of the incident angle θ at a corresponding position determined on the bottom surface of the glass plate 6 from the incident angle θ of the sunlight with respect to the optical axis of the slit 5 is provided. Is placed.

The gray cord pattern portion 7 is disposed on the bottom surface of the glass plate 6 perpendicular to the longitudinal direction (hereinafter referred to as the longitudinal axis) of the cylinder lens 4 to the optical path of the sunlight beam on the bottom surface of the glass plate 6. It is arranged to process the angle of incidence according to the distance from the optical axis of the cylinder lens 4 with respect to. Each of these patterns corresponds to a bit indicating on / off, and the gray code shown as on / off of these bits is read and the value is converted into an angle.

Each part of the digital solar sensor operated as mentioned above is demonstrated separately.

The light receiving portion is composed of a cylinder lens 4, a slit 5, and a glass plate 6.

The cylinder lens 4 is used to induce an efficient image formation according to the angle of incidence of sunlight, and is provided for making an image of a form that is easy to process the sunlight rays propagated into outer space. Such a slit 5 has a uniform width along the longitudinal axis of the cylinder lens 4, and is easily made by coating with a coating material that blocks light on a portion except the width of the slit 5 set on the upper surface of the glass plate 6. Can be. In addition, the width of the slit 5 is affected by the desired precision, the sensitivity of the solar cell 31 which is a photoelectric conversion element, and the degree of diffraction. If a sufficient signal is desired, the width of the slit 5 should be large, but if it is too large, There is a problem with accuracy. Therefore, the width of the slit 5 should be determined so that the influence of diffraction is sufficiently small in the viewing angle which is the observable area.

The gray code pattern part 7 includes a sine bit part 12 in which patterns are formed to determine an orientation of sunlight incident on the optical axis of the slit 5, and a gray code part in which patterns are formed to provide incident angle information of the sunlight. (13, 14), automatic threshold adjustment bit section 11 in which a pattern is formed to provide a signal as a reference for determining on / off of sunlight passing through the light transmission window of the gray code sections 13 and 14; It consists of.

The gray code pattern portion 7 is composed of a pattern of 14 bits in total, and each pattern (hereinafter referred to as a bit) is composed of a light transmitting window that transmits one to several lights, and a preferable gray code pattern portion 7 ) Will be described in detail with reference to FIG. 3.

The gray code pattern portion 7 is designed by the relationship between the thickness of the glass plate 6 and the incident angle θ. The characteristics of each bit portion are as follows.

The auto-threshold adjustment bit 11 corresponding to the auto-threshold adjustment bit section 11 is arranged in outline bits (first sign bits, first outline bits to sixth outline bits, and first fine bits) in charge of the incident angle information. It is a bit used as a reference for determining whether or not sunlight is incident on a corresponding light transmission window, that is, determining on / off of each bit.

When the incident angle of solar light is θ, the output voltage of solar cell is proportional to COSθ, so it is impossible to fix the reference value for on / off of each bit to a specific value. Therefore, a bit having a reference value that is variable according to the incident angle is required. The automatic threshold adjustment bit 11 is formed to correspond to the viewing angle of the slit 5 across the longitudinal axis of the slit 5 with a width corresponding to half of the pattern width of the bits for processing the incident angle. Therefore, the output current of the solar cell output through the width of the automatic threshold adjustment bit 11 is also half the output current of the bit for processing the incident angle. Therefore, if the voltage output from the solar cell through each bit responsible for incident angle information is more than half of the output voltage of the solar cell output through the automatic threshold adjustment bit 11, the corresponding bit is determined to be on, and if less than half, the off is off. Determination processing

Another method may be to form a light transmission window having the same width as the other bits, and then compare the other bit with a value corresponding to half of the current output through the automatic threshold adjustment bit 11 from the electronic circuit unit 50.

The sine bit portion 12 is a bit for determining whether the sunlight is placed in the correct direction with respect to the light receiving surface of the digital solar sensor. The sine bit portion 12 is the left side of the sunlight around the optical axis of the slit 5. Ooh. Prize. It is formed to determine the orientation of the under.

The sign bit section 12 is composed of three bits consisting of a first sign bit 12a, a second sign bit 12b, and a third sign bit 12c.

The bit having a field of view corresponding to half of the field of view of the digital solar sensor is the first sine bit 12a, which is formed of a single light transmission window 12a through which half passes through the optical axis of the cylinder lens 4, and gray. The second sign bit 12b and the third sign bit 12c positioned at the outermost sides of the code pattern part 7 are bits for detecting sunlight in the up-down direction of the slit 5.

When the sunlight is incident on both of the second sign bit 12b and the third sign bit 12c, the left and right sides of the incident angle are determined from the electrical signal output through the first sign bit 12a. The electronic circuit section 50 is configured to determine +, denoted by-.

That is, when the output signals of the second sign bit 12b and the third sign bit 12c are on, it indicates that the sun is within the viewing angle range in the plane perpendicular to the optical axis of the digital solar sensor. Since the second sign bit 12a and the third sign bit 12c are half in width, they are used to reference the amount of incident light.

The gray code portion is composed of the rough bit portion 13 and the fine bit portion 14 so as to read the incident angle information of the sunlight. Such a gray code part divides the viewing angle of the slit 5 by a predetermined angle, and arrange | positions a light transmission window alternately in the position area on the bottom surface of the glass plate 6 corresponding to this divided angle, and acquires incident angle information. That is, when sunlight is transmitted through the pattern (that is, the bit) formed by the light transmission window corresponding to the set angle width, it is turned on, and it can be seen that there is an angle of incidence within the angle measurement range (hereinafter referred to as visual field) of the light transmission window. In this case, each bit has a different field of view and is composed of a plurality of light emitting windows that can increase the accuracy of the measurement angle by combining with each other.

The outline bit portion 13 is composed of a total of six bits consisting of the first outline bit 13a to the sixth outline bit 13f, and a pattern corresponding to the bit is formed to process the incident angle information up to one degree unit.

The first outline bit 13a has a field of view of +32 degrees and -32 degrees and is arranged in one floodlight window.

The second outline bit 13b is arranged in two light transmission windows and is +48 degrees to +16 degrees and -16 degrees to -48 degrees from the left, respectively, based on the center line on the pattern corresponding to the longitudinal axis of the cylinder lens 4. In charge.

The third outline bit 13c is arranged in four light emitting windows and is +56 degrees to +40 degrees, +24 degrees to +8 degrees, -8 degrees to -24 degrees, and -40 degrees to the left from the left with respect to the center line, respectively. It has a field of view of -56 degrees.

The fourth outline bit 13d is arranged with eight light emitting windows and is +60 degrees to +52 degrees, +44 degrees to +36 degrees, +28 degrees to +20 degrees, and +12 degrees to the left from the left with respect to the center line. +4 degrees, -4 degrees to -12 degrees, -20 degrees to -28 degrees, -36 degrees to -44 degrees, and -52 degrees to -60 degrees.

The fifth outline bit 13e is arranged with 16 light emitting windows and is +62 degrees to +58 degrees, +54 degrees to +50 degrees, +46 degrees to +42 degrees, and +38 degrees to the left from the left with respect to the center line. +34 degrees, +30 degrees to +26 degrees, +22 degrees to +18 degrees, +14 degrees to +10 degrees, +6 degrees to +2 degrees, -2 degrees to -6 degrees, -10 degrees to -14 Degrees, -18 degrees to -22 degrees, -26 degrees to -30 degrees, -34 degrees to -38 degrees, -42 degrees to -46 degrees, -50 degrees to -54 degrees, -58 degrees to -62 degrees In charge.

The sixth outline bit 13f is arranged in 32 light emitting windows and has a field of view of 2 degrees (ie, +61 degrees to +63 degrees, ..., +3 degrees to 1 degree, -1 degrees to -3 degrees, -61 degrees). To -63 degrees) and arranged symmetrically on the centerline.

Unlike the rough bit section 13, the fine bit section 14 does not turn on / off the signal but combines the incident amount of sunlight incident on a few bits to increase the measurement accuracy.

Digital solar sensor resolution is limited by the number of bits (ie, the number of patterns). It is proportional to (N: number of bits), and as described above, since the sun is close to the satellite, the number of bits cannot be increased indefinitely, and separate signal processing is required to have a resolution within 0.52 degrees. The fine bit portion 14 is formed with a pattern to process up to 0.25 degrees.

The fine bit section 14 is composed of a total of four bits consisting of the first fine bit 14a to the fourth fine bit 14d, and the viewing range of one floodlight window corresponds to 1 degree. Corresponding light windows of each bit with respect to the incident light are staggered from each other, consequently contributing to a resolution of 0.25 degrees divided by 1 degree.

Except for the fine bit portion 14, in which one floodlight window covers the field of view of 1 degree, the remaining bits only turn on / off the incident of sunlight, so regardless of the shape of the image formed in the solar cell, the fine bit portion 14 Depends on the amount of energy to form in the solar cell, so the size of the formed phase should be less than or equal to the width of the floodlight.

The photoelectric conversion unit 30 is composed of a solar cell 31, which is a photoelectric conversion element that is attached to the pattern corresponding to the bit, respectively, and converts the optical signal incident through each bit into a current signal and outputs it.

The incidence angle information of sunlight passes through the gray code pattern portion 7 and is output as a current signal through a solar cell corresponding to a bit of each pattern, and the electronic circuit portion 50 calculates the incidence angle from the current signal.

The electronic circuit portion of the digital solar sensor is described with reference to FIG. 4, which shows a block diagram.

The electronic circuit unit 50 is roughly divided into a visual field processing unit 51, a rough bit calculating unit 60, a fine bit calculating unit 70, a buffer 80, a display unit 90, and a control unit 100.

The outline bit operation unit 60 includes eight signals simultaneously applied through the respective solar cells in the first sign bit 12a, the first outline bit 13a through the sixth outline bit 13f, and the first fine bit 14a. The incident angle is read out from the gray code value obtained by comparing the electrical signal with the electrical signal applied through the solar cell from the automatic threshold adjustment bit 11, and the resolution of the incident angle is calculated to 1 degree.

The fine bit calculator 70 reads the incident angle within 1 degree range from the four electrical signals applied through the respective solar cells in the first fine bit 14a to the fourth fine bit 14d, and resolves the resolution of the incident angle. Calculate up to 0.25 degrees.

The visual field processing unit 51 determines whether the incident angle of sunlight can be processed from the electrical signal applied through each solar cell in the second sign bit 12b and the third sign bit 12c, and outputs the result.

The buffer 80 temporarily stores the incident angle information applied from the coarse bit calculator 60 and the fine bit calculator 70 and outputs the incident angle information to the display 90. The incident angle data output of the buffer 80 is controlled by the visual field processing unit 51, and is output when the visual field processing unit 51 determines that the incident angle range of sunlight is appropriate.

Indicator 90 displays the angle of incidence applied from buffer 80.

In addition, since the incident angle information of the sunlight is divided into a rough bit calculation unit 60 for processing an angle range of 1 degree or more and a fine bit calculation unit 70 for processing within 1 degree, data values output from the two calculation units are synchronized. Should be. The control unit 100 controls the signal processing in this manner.

Hereinafter, each part of the electronic circuit unit will be described in more detail.

For reference, reference numerals 52, 53, 62, and 63 shown are amplifiers for amplifying an electrical signal output through a solar cell.

The outline bit calculation unit 60 is roughly divided into a switching unit 61, a gray code conversion unit 65, and a comparison unit 66.

Electrical signals applied from the first sign bit 12a, the six coarse bits 13a to 13f, and the first fine bit 14a are sequentially output from the switching unit 61. The sequentially output signal is compared with the electrical signal of the automatic threshold adjustment bit 11 in the comparator 64 and then applied to the gray code converter 65. Eight data sequentially input through the comparator 64 become one gray code value, and this value is converted into a binary value by the gray code conversion unit 65 and outputted. This output is output in parallel with 8 bits. The parallel data output in parallel is applied to the comparator 66. The comparing unit 66 compares the least significant bit of the 8-bit binary data with the most significant bit of the binary data processed by the fine bit calculating unit 70 and outputs the same value to the buffer 80 if it is not the same. Replace with the value processed in (70).

The fine bit calculation unit 70 includes a phase control unit 71, a DC control unit 72, a band pass filter (BPF) unit 73, a square wave conversion unit 74, a gate adjusting unit 75, and a binary conversion unit 76. It is roughly divided into.

The signals applied from the four fine bits 14a to 14d are sequentially controlled by the phase controller 71 to control the analog signals from each fine bit, and the four signals are converted into one square wave and output. After the direct current component included in the square wave signal is removed by the direct current control means 72, it becomes a sine wave through the band pass filter 73. The square wave is output by converting the square wave converter 74 into a "high" signal when the voltage is higher than zero voltage based on the zero voltage of the sinusoidal wave. The square wave signal is adjusted by the gate adjusting unit 75 so as to be output within the reference wave pulse range set by the control unit 100. The adjusted signal outputs a binary value corresponding to the corresponding angle as an 8-bit binary data signal based on the corresponding frequency of the clock by the binary converter 76. This value has a resolution of up to 0.004 degrees. The binary value corresponding to the most significant bit of the binary data is input to the comparator 66 of the rough bit calculator 60, and the remaining bits are output to the buffer 80. As mentioned above, the most significant bit of the binary data is compared with the least significant bit of the binary data obtained by the rough bit calculation unit 60. If the two values are compared and output as they are, the same value is output. However, if the values are different, the most significant bit value of the fine bit calculation unit 70 is output.

The binary data output from the comparator 66 and the binary data output from the binary converter are input to the buffer 80, and the data are sequentially arranged to apply an output value to the display.

The visual field processor 51 outputs an output control signal of the buffer 80 to output data temporarily stored in the buffer 80 when the electrical signals from the second sign bit 12b and the third sign bit 12c are turned on at the same time. Is authorized. That is, when the signals of the second sign bit 12b and the third sign bit 12c are input to the AND gate 54, and the output signal is "high", the data stored in the buffer 80 is displayed on the display 90. Is authorized.

The incident angle measurement accuracy of the digital solar sensor depends on the degree of registration in which the gray code pattern portion 7 is coupled to the glass plate 6, and the degree to which the width of the light emitting window that is responsible for the field of view of each pattern matches the calculated width.

In order to optimize the factors contributing to such precision, the manufacturing method of the gray code pattern portion 7 according to the present invention will be described below.

The design of the gray cord pattern is determined from the thickness of the glass plate 6. The pattern designed in this way is coated on the film surface to make a mask, and the gray cord is etched on the bottom surface of the glass plate 6 using the mask.

There are many ways to make a mask. The simplest way is to print directly onto the film using a laser printer with precise resolution. This method is less accurate due to not only the resolution of the laser printer itself but also the physical error in the printing process and the resolution reduction due to the reduction and magnification process, and the desired precision is obtained when the minimum width of the fine bitlight window is hundreds of micrometers. Hard.

Therefore, the preferred method of manufacturing the mask is manufactured using the art working technology of the PCB.

When the production of the full-scale mask film is completed, the etching is under the glass plate (6). First, the material to be coated is coated on the glass plate 6 and the photoresist is applied again. Place the mask on the photoresist and shine the light. The light passing through the mask pattern by the split light cures the photoresist, and the cured part is transmitted without blocking light in the mask pattern. The hardened glass plate 6 is immersed in a solution for dissolving the uncured photoresist, and the portions except the hardened portions are melted. When the recoated material is immersed in the dissolving solution, only the couple without the hardened photoresist melts, and finally a gray code pattern is formed on the bottom of the glass plate 6. Since this coating material should block light, it should be a light absorbing material, preferably chromium.

The features of the digital solar sensor of the present invention described so far are summarized as follows.

Since the incident angle resolution of sunlight is improved and the output of the gray code pattern that provides incident angle information is a digital signal, there is no need for a separate A / D conversion, so it can be processed immediately by amplification, and its power consumption is small and its size is reduced. It can be reduced, and the reference point for judging whether or not sunlight is incident is flexible, so that it is not influenced by earth reflection and is not greatly affected by the aging and characteristic error of the photodetector used.

Claims (11)

A light receiving unit having a cylinder lens disposed on an upper surface of the glass plate having a uniform thickness, and a slit having a uniform width along the longitudinal axis of the cylinder lens formed between the upper surface of the glass plate and the cylinder lens; One or more patterns arranged in a line with a light emitting window having a predetermined size are arranged side by side on the bottom surface of the glass plate, and the pattern corresponding to the bit of the gray code has a large number of viewing angles of the slit at a predetermined equal angle. The light-transmitting window is alternately arranged in a position area on the bottom surface of the glass plate corresponding to the optical path incident into each division angle by dividing, so that the projection window is alternately arranged at a predetermined angle with respect to the optical axis of the slit in each pattern having different division angles. A gray code pattern unit that selectively transmits incident sunlight to provide on / off information of the bits; A photoelectric conversion unit disposed to correspond to each of the patterns, the photoelectric conversion unit receiving the solar light incident through the light transmission window of the pattern and converting the received sunlight into an electrical signal; And And an electronic circuit unit for calculating and displaying the angle of incidence from the electrical signal. The method of claim 1, wherein the gray code pattern portion A sine bit unit in which patterns are formed to determine an orientation of the sunlight; A gray code part in which patterns are formed to provide the incident angle information; And And an automatic threshold adjustment bit part having a pattern formed thereon to provide a signal which is a comparison reference for determining on / off of the sunlight passing through the light transmission window of the gray code part pattern. The method of claim 2, wherein the sign bit unit A first sine bit having a pattern formed by a single light transmission window on only one side of the longitudinal axis to determine the left and right sides of the azimuth; A second sign bit having a pattern formed by one light transmission window crossing the longitudinal axis to determine an upward direction of the azimuth, and disposed below the gray code part on a bottom surface of the glass plate; And And a third sign bit formed on the gray cord part on the bottom surface of the glass plate, the pattern being formed by a single light transmission window crossing the longitudinal axis to determine the downward direction of the azimuth. Solar sensor. The method of claim 2, wherein the gray code portion An approximate bit section comprising six patterns each having 64 degrees, 32 degrees, 16 degrees, 8 degrees, 4 degrees, and 2 degrees with respect to the optical axis; And The first fine pattern having the equal dividing angle of about 1 degree with respect to the optical axis, and the even dividing angle of the first fine pattern having a degree of 1 degree with respect to the light transmission window arrangement of the first fine pattern, are sequentially disposed with respect to the longitudinal axis, and thus the first fine pattern is disposed. And a fine bit portion having a second fine pattern, a third fine pattern, and a fourth fine pattern, the pattern being formed to process the 1 degree range of the fine pattern by 0.25 degrees. The electronic circuit of claim 3, wherein the electronic circuit unit A fine bit calculator configured to convert an electrical signal applied through each channel of the first to fourth fine patterns into a binarization code and output the binary signal; The first sign bit of the sine bit portion formed by a single light transmission window on one side of the longitudinal axis to determine the right and left of the azimuth, the coarse bit portion formed of a pattern different from each other around the optical axis A schematic bit calculator for converting an 8-bit gray code value obtained from an electrical signal of 8 channels applied through each channel of the six patterns and the first fine pattern into a binary signal; And a buffer for sequentially arranging an output signal of the coarse bit calculator and an output signal of the fine bit calculator, and outputting the output signal by a control signal applied from the field processing unit. The apparatus of claim 5, wherein the coarse bit calculating unit A switching unit for sequentially switching and outputting an electrical signal input through the eight channels; A comparator for outputting an on / off bit value by comparing an electrical signal output from the switching unit with an electrical signal of the automatic threshold adjustment bit unit; And a gray code conversion unit for converting the gray code values formed by accumulating the on / off bit values sequentially input into binary values and outputting the binary codes. The method of claim 6, wherein the rough bit operation unit And a comparison unit for comparing the least significant bit of the binary value with the most significant bit of the binarization code calculated by the fine bit operation unit, outputting the same value, and correcting the error when an error occurs. The method of claim 5, wherein the fine bit operation unit A phase controller configured to sequentially control and output a phase of an electrical signal applied through four channels output through the first to fourth fine patterns; DC control means for outputting a sine wave of only the AC component by removing the DC component of the signal applied from the phase control unit; A square wave converter for converting the applied sinusoidal potentials into square wave pulses and outputting the square wave pulses; A gate adjuster for controlling and outputting the square wave pulse to be output within a set reference wave pulse range; And a binary converter converting the binary signal from the signal output from the gate controller and outputting the binary value to the buffer. The method of claim 8, wherein the fine bit operation unit And a band pass filter unit inserted between the DC control unit and the square wave conversion unit to remove noise outside the set frequency band. The method of claim 1, wherein the slit A digital solar sensor, characterized in that the glass plate is coated with a material for shielding light except for the width of the slit. The digital solar sensor according to claim 1, wherein the gray cord pattern part forms the floodlight by etching chromium coated on the bottom of the glass plate.