# Sun angular coordinate indicator

FIELD: instrument engineering.

SUBSTANCE: device has optical spectrum filter, slit mask, multi-element photo-sensitive detector, threshold elements, photo-detector register, counter, output register, clock pulse generator. Multi-element photo-sensitive detector consists of elementary photo-detectors placed behind one another along quadratic curve. Normal lines to sensitive areas of each elementary photo-detector and quadratic curve lie in same plane.

EFFECT: higher effectiveness and efficiency.

1 dwg

The sensor is intended for determining the angular coordinates of the luminous reference point and, in particular, to determine the direction of the Sun in the coordinate system of the spacecraft.

The closest to the technical nature of the claimed sensor is the sensor [1], consisting of two identical channels that are used to measure angular coordinates in two mutually orthogonal planes. Each channel consists of a linear charge-coupled device, on which at a given distance in parallel planes are optical attenuation filter, the optical band-pass filter and a slit mask. In addition, each channel has: a generator of clock pulses, a signal amplifier of the charge-coupled device, a threshold device, a pulse counter, the output register and the device for storing the sign of the presence of the Sun. At the output of the sensor is formed by a digital code corresponding to the sequence number of the photosensitive element of the charge-coupled device, which is the average in the group of photosensitive elements, illuminated through the slit in the mask sunlight.

The disadvantage of this sensor is to run to find the angular coordinates of the formula

α=arctan[x(n-(N+1)/2)/d]

where α - angular coordinate; d is the distance from the surface of the device scaradavou connection to the plane which is slit mask; x - step arrangement of photosensitive elements, n is the sequence number of the photosensitive element, which is the average in the group of photosensitive elements, illuminated by the solar rays, N is the total number of photosensitive elements in the charge-coupled device.

Another disadvantage is the small size of the field of view 66°(±33°), due to the discreteness of the charge-coupled device and the accuracy of calculation of functions of the form γ=arctan(x) for values larger than 1.

The aim of the invention is to obtain angular coordinates without performing computational operations and the expansion of the field of view.

This goal is achieved by the fact that the inventive sensor comprises a multi-element photosensitive receiver, and photosensitive elements are arranged not in a straight line in the plane and on the curve, in particular on the arc of a circle, resulting in the angular coordinate of the Sun is associated with the number of middle-lit elementary photodetector through the expression

α=[n-(N+1)/2]γ,

where α - angular coordinate; γ - angular spacing of photosensitive elements, n is the sequence number of the photosensitive element, which is the average in the group of photosensitive elements, illuminated by a ray of sunlight is mi, N is the total number of photosensitive elements in multi-element photodetector. That is, there is a linear relationship between the angular coordinate and the average number of the photosensitive element.

The device proposed sensor portion of a sensor and a slit mask illustrated drawings, in which 1 - multi-element photodetector; 2 - one of the elementary photodetectors; 3 - angular spacing of the elementary photosensitive elements; 4 - axis; 5 - a crack in the mask 6 is the angular coordinate of the Sun; 7 - Sun.

The sensor also includes a threshold device, the register sensor pulse counter output register clock.

Does the sensor in the following way. The sun's rays that have passed through the slit mask are transferred to the multi-element photosensitive receiver, where it is converted into an electrical signal. The electrical signal from each elementary sensor is fed to a threshold device for converting into a digital signal, which assumes the value of logical zero or one depending on whether illuminated photosensitive element or not. The output signals of the threshold devices are recorded in the register of the photodetector, which is read by the command sequentially and synchronously with the clock pulses. Simultaneously with the beginning of the output is ignal from the register of the photodetector, the counter begins to count clock pulses. As soon as the output register of a sensor a signal corresponding to the illuminated elementary photodetector, the counter starts counting pulses with a frequency of 2 times lower than the clock frequency. Then, as soon as the output register of the photodetector will receive a signal corresponding unlit elementary photodetector, the counter stops the account, and the received counter code is stored in the output register. Thus, the number of middle-lit elementary sensor and accordingly the angular coordinate of the Sun.

Multi-element photodetector can be fabricated by planar technology of the known semiconductor materials. Getting photosensitive elements that lie on a given curve, is due to the cut in the semiconductor wafer holes defined profile with a laser.

Comparative analysis with the prototype shows that the proposed sensor differs from the prototype there is no need to compute the value functions of the form arctan[x(n-(N+1)/2)/d].

No trigonometric calculations allows to extend the field of view of the sensor and when the sensor on Board the spacecraft to reduce the time required to determine the spatial orientation, which increases the reliability of the spacecraft which reduces its power consumption.

The source of information

1. Patent USA No. 4794245, NCI 250/203R, 1988.

The sensor of angular coordinates of the Sun contains the optical spectral filter, slit mask, multi-element photosensitive receiver, the threshold elements, the case of a sensor, a counter, an output register, a clock, wherein the multi-element photosensitive receiver consists of elementary photodetectors, which are located one behind the other on the curve of the second order in such a way that the normal to sensitive areas of each elementary sensor and a curve of the second order lie in the same plane.

**Same patents:**

FIELD: instrument engineering.

SUBSTANCE: device has optical spectrum filter, slit mask, multi-element photo-sensitive detector, threshold elements, photo-detector register, counter, output register, clock pulse generator. Multi-element photo-sensitive detector consists of elementary photo-detectors placed behind one another along quadratic curve. Normal lines to sensitive areas of each elementary photo-detector and quadratic curve lie in same plane.

EFFECT: higher effectiveness and efficiency.

1 dwg

FIELD: programmed positioning and orientation of mobile objects; angular orientation or positioning of spacecraft.

SUBSTANCE: proposed method includes measurement of angles of position of optical axes of astro-visual units tracking the stars relative to body-axis coordinate system. For determination of orientation of mobile object, use is made of coordinates of its center of mass in geocentric coordinate system which are determined by means of high-precision global navigation satellite system.

EFFECT: enhanced accuracy of orientation of mobile objects.

2 dwg

FIELD: rocketry, spacecraft engineering, possible use for detecting direction of bearing rocket in flight.

SUBSTANCE: satellite navigation equipment and three gyro-integrators simultaneously determine values of projections of speed vector in starting and connected coordinates system respectively and transfer determined values to onboard digital computing machine, which, using received information, determines values of angles of orientation of moving object in space in accordance to algorithm for determining orientation of moving object.

EFFECT: decreased dimensions of device for realization of proposed method down to 40x40x40 millimeters (without consideration for size of onboard digital computing machine) while maintaining precision for determining angles of direction of moving object to 4 angular minutes.

2 cl, 4 dwg

FIELD: instrument industry.

SUBSTANCE: method comprises autonomous determination of the position of the instrument with respect to the horizontal plane coordinate system from the signals from the accelerometers and vector conforming of the coordinate systems for determining the position of the instrument coordinate system in azimuth.

EFFECT: enhanced precision.

1 dwg

FIELD: measuring technique.

SUBSTANCE: method comprises determining the vector of velocity of the object in a Cartesian coordinate system, determining integral characteristics of the variation of the velocity vector as a function of the direction of motion of the object in the space, and stabilizing the trajectory of motion of the movable object on the basis of the estimations depending on the direction chosen from the stars sky.

EFFECT: enhanced reliability.

FIELD: instrument industry.

SUBSTANCE: device comprises two spheres mounted with a spaced relation one to the other. The outer sphere is made of a superconducting material, and the inner sphere is made of a magnetic material. The outer sphere is secured to the spacecraft, and the inner sphere is shifted with respect to the center of gravity and has the radiation source. The output of the radiation receiving unit is connected with the information input of the recording unit whose control input is connected with the output of the board control unit.

EFFECT: simplified structure.

5 cl, 2 dwg

FIELD: measurement technology.

SUBSTANCE: method can be used in moving objects' spatial orientation systems. Before beginning of movement of object, the coordinate system is chosen being comfortable for observer. Three stars are selected, along directions of which stars the speeds have to be measured and their angular coordinates are measured. After movement starts, current values of linear velocity are measured on the base of directions of navigating stars. Changes in linear velocity are calculated from directions of navigating stars, which are changes are caused by rotation of object, and basic components of angular speed vector are determined from directions of navigating stars.

EFFECT: improved precision of measurement.

FIELD: measuring equipment, applicable for determination of the Sun angular coordinates in the spacecraft coordinate system.

SUBSTANCE: the Sun attitude pickup has an optical system made in the form of a wide-angle lens including an inlet and outlet plano-convex lenses with a diaphragm placed between them, an optical element is positioned in its holes, matrix photodetector, and a unit for processing of information and computation of coordinates. The refractive indices of the optical components are selected proceeding from the relation: n_{1}≥n_{2}<n_{3}, where n_{1} - the refractive index of the inlet plano-convex lens; n_{2} - the refractive index of the optical element; n_{3} - the refractive index of the outlet plano-convex lens.

EFFECT: obtained information in a wide angular field with a high precision.

3 cl, 1 dwg