RU2580908C1 - Method of determining spatial position of objects and apparatus therefor - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: method of determining the spatial position of objects comprises irradiating an object through a two-dimensional diffraction grating, which enables to form an array of adjacent optical channels. Each optical channel is given a certain angular direction. A signal in each optical channel reaches the corresponding element of an array of radiation detectors, and the range to a point on the object is calculated in each optical channel. In the apparatus which implements the said method, a laser emitter is provided with a beam expander, behind which the two-dimensional diffraction grating is placed. The radiation detector is in the form of an array of elements which are optically interfaced through a receiving lens with a diffraction pattern, the laser radiation control unit is in the form of a modulator and a reference signal generator, simultaneously connected to the modulator and a processor.

EFFECT: faster operation when generating a cloud of points which define the angular coordinates and range of each reflecting area of an object.

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Description

The invention relates to measuring equipment and, in particular, can be used to simultaneously measure the distance to objects in the field of view, their angular coordinates and relative position.

A known method of detecting objects, measuring speed, range and angular coordinates, consisting in radiation in the direction of the field of view of the light pulse, for example, using infrared LEDs and detecting reflected light pulses, for example, using photosensitive elements. When a single light pulse is emitted from objects in the field of view located at different angular coordinates and different distances, many light pulses are reflected, which are focused and detected by photosensitive elements. The position of the photosensitive element to which the reflected light pulse arrives determines the angular coordinates of the object in the field of view, from which the signal corresponding to the detected light pulse is received. The light pulse, due to the Doppler effect, when reflected from a moving object, changes its duration - increases if the object moves away, and decreases if the object approaches, while the carrier frequency and the modulation frequency of the signal change. A change in the carrier frequency upon reflection from a moving object leads to a change in the duration of the reflected light pulse. The signals from the reflected light pulses detected on photosensitive elements are digitized [Method for detecting objects, measuring speed, range and angular coordinates and device for its implementation [RF Patent No. 2521203 C1, M.cl. G01C 3/08; G01S 17/58; G01P 3/36 of 12/27/2012].

The disadvantage of this method is the limited field of view due to the narrow radiation pattern.

Known facet optoelectronic systems, the field of view of which is blocked by many optical channels consisting of a lens and a radiation receiver (Device for detecting and measuring the azimuthal angle of light-emitting pulsed objects, [RF patent No. 2494343 C1, Mcl G01C 1/00 from 10.04 .2012]]. Such systems have high speed, but do not provide a measurement of the distance to the object, which is their drawback.

The closest in technical essence and the achieved result is the method of ground-based laser scanning, which consists in the direction of laser pulsed radiation with a small angle of divergence to objects, scanning with laser radiation of the field of view using an optical-mechanical system with simultaneous measurement of the angular coordinates of directed radiation, reception (detection) reflected pulses, digitizing received signals, calculating the distance to the object from the time of arrival of pulses for each angular ION and forming a cloud of points defining the distance and the angular coordinates of each reflection site (point) of the object. The method is implemented in devices of ground-based laser scanners [Monograph “Ground-based laser scanning”: V.A. Seredovich, A.V. Komissarov, D.V. Komissarov, T.A. Shirokova. - Novosibirsk: SSGA, 2009. - 261 p., P. 9].

The disadvantage of this method is the low speed due to optical-mechanical scanning.

The aim of the invention is to improve performance when forming a cloud of points that determine the angular coordinates and the range of each reflecting area of the object.

This goal is achieved by the fact that the object is irradiated in a variety of directions formed by a two-dimensional diffraction grating, which together cover the field of view and form a matrix of adjacent optical channels, while each optical channel is assigned a certain angular direction, the signal in each optical channel is supplied to the corresponding element of the matrix of radiation receivers , and the distance to the point of the object is calculated in each of the optical channels, while in the device that implements the method, the laser emitter beam expander, which is set for a two-dimensional diffraction grating, the radiation receiver is formed as a matrix element, optically coupled via a receiving lens with a diffraction pattern, and laser light emission control unit is designed as a modulator and a reference signal generator, connected to both the modulator and the processor.

The essence of the invention is illustrated by the drawing, where: 1 - laser, 2 - beam expander, 3 - diffraction grating, 4 - diffraction pattern in the space of objects, 5 - receiving lens, 6 - matrix of radiation receivers, 7 - multi-channel phase meter, 8 - processor , 9 - reference signal generator, 10 - modulator.

The method is implemented as follows.

With the help of a laser emitter, a multitude of laser beams are created in the space of objects, forming a spatial structure in the form of a grid with a uniform arrangement of the beams in orthogonal directions.

. Угловое поле приемного объектива охватывает определенную часть дифракционной картины, определяемую размерами чувствительной поверхности матрицы приемников излучения и фокусным расстоянием объектива. Матрица 6 содержит m x n элементов, каждый из которых воспринимает поток излучения в определенном постоянном направлении. По отраженным от объекта пучкам излучения в каждом направлении измеряют дальность до отражающего элемента объекта. В результате измерений получают массив (облако) точек, для каждой из которых известны угловое направление и дальность.The beam expander 2 of the laser emitter is a telescopic system with an increase sufficient to irradiate a two-dimensional diffraction grating 3, consisting of a grid of holes located at the same pitch (period) along the orthogonal axes. The diffraction angle θ is determined by the size of the hole and the wavelength of laser radiation 1. The diffraction pattern in the space of objects contains maxima located at a certain constant interval. With the rectangular shape of the holes with side a, this interval is equal in angular measure

. The angular field of the receiving lens covers a certain part of the diffraction pattern, determined by the size of the sensitive surface of the matrix of radiation receivers and the focal length of the lens. Matrix 6 contains mxn elements, each of which perceives the radiation flux in a certain constant direction. The radiation beams reflected from the object in each direction measure the distance to the reflecting element of the object. As a result of measurements, an array (cloud) of points is obtained, for each of which the angular direction and range are known.

The device operates as follows.

The reference signal generator 9 generates a high-frequency carrier frequency signal that, through the modulator 10, controls the laser radiation. Laser 1 emits a corresponding continuous harmonic radiation with a constant initial phase. The laser beam is collimated by the beam expander 2 and irradiates the diffraction grating 3. As a result of diffraction in the space of objects, a diffraction pattern 4 is created in the form of a combination of narrow optical beams irradiating the object. The radiation reflected from the object is received by the lens 5, in the focal plane of which there is a matrix of radiation detectors 6. When the radiation propagates in each optical channel, a phase difference arises between the reference signal and the signal reflected from the object, proportional to the distance to the corresponding element of the object reflecting the signal. The signals from the elements of the matrix are fed into a multi-channel phasemeter 7, which measures the phase shift in each channel. The processor 8 calculates the distances to the surface elements of the object in each direction determined by the diffraction angle, while certain elements of the matrix of radiation receivers receive the flow only in the corresponding direction, and therefore the direction to the element of the reflecting surface is determined by the number of the element in the matrix of radiation receivers. Thus, the processor 8, forms an array of coordinates of each surface of the object (range and angular coordinates along two axes).

Claims (2)

1. The method of determining the spatial position of objects, which consists in the direction of laser radiation in the field of view, detecting reflected optical signals, calculating the distances to the points of objects in the field of view while measuring the angular direction to these points and transmitting the results of measurements and calculations to external control devices, characterized the fact that the object is irradiated in a multitude of directions formed by the two-dimensional diffraction grating, which in the aggregate cover the field of view and form a matrix of adjacent optical channels, while each optical channel is given a diffractive angular direction, the signal in each optical channel is supplied to an element of the matrix of radiation receivers corresponding to the diffractive direction, and the distance to the object point is calculated in each of the optical channels. 2. A device for determining the spatial position of objects containing a laser emitter, a receiving optical system, a radiation receiver, a laser radiation control unit, a processor, an external control unit, characterized in that the laser emitter is equipped with a beam expander, behind which there is a two-dimensional diffraction grating, a radiation receiver made in the form of a matrix of elements optically coupled through a receiving lens with a diffraction pattern, and the laser radiation control unit is made in the form of a modulator and a gene a reference signal driver connected simultaneously to the modulator and processor.