The method of measuring the phase distribution of the multi-element cross interferometer
(57) Abstract:The method of measuring the phase distribution of the multi-element cross interferometer refers to the measurement and can be used in various two-dimensional interferometers. The technical result is reduction of the RMS errors of the phase of the signal distribution on the aperture to 5-6 degrees, which significantly improves the shape of the beam cross interferometer, and this in turn reduces the error analysis of the structure of two-dimensional images of active regions on the Sun. In addition, this method dozens of times reduces the time of receipt of the phase distribution across the aperture. The method consists in the fact that analyze the image spectrum of small local source in the Sun, built in the coordinate system of the guides of the cosines, where the phase distortion in the antenna-feeder path appear parallel to the axes of the spectrum of spatial frequencies of the interferometers (East-West, North-South). The invention relates to radio astronomy, and is intended to receive radio images of the Sun, not distorted by the phase error of the signal distribution on the aperture Dulcinea growth of side lobes.A method of obtaining the phase distribution of the signals of the multi-element grating successive registration of the summary of responses from the two neighboring antennas for the period of the interference pattern (Krissinel B. B. "Methods of phasing and beam arrays microwave range" - In the book. "Research on Geomagnetism, Aeronomy and Solar physics"), Nauka, 1977, vol. 42, S. 142). Further in this way analyze phase responses, comparing them with the phase of the 1st harmonic of the image from the opposite shoulder cross interferometer.The disadvantages of this method are the length of the phase distribution across the aperture (2-3 minutes for one pair of antennas), which increases the total time to 13-14 hours. This, ultimately, leads to the loss of the optimal observation time, and also use additional microwave devices for modulation of the measured pairs and locking the other antenna and a separate receiving and recording system. In addition, a known method peculiar to the presence of systematic errors due to changes of the center of gravity of the radio emission of the Sun over time (including due to changes in Solar activity).The purpose of testoobraznogo interferometer 20 to 30 minutes, which leads to a considerable increase of efficiency of use of the tool. In addition, the proposed method does not require additional microwave devices and a separate receiving equipment, and eliminates the systematic errors associated with the change of center of gravity of the radio emission of the Sun over time.The invention: the proposed method on the interferometer register the image of the Sun, choose it local source with the size of the order or smaller than the pattern width of the tool, get the spatial spectrum of this source, then from the spectrum get the desired phase distribution. For the implementation of the proposed method using known radio devices, namely cross-shaped interferometer with databases 623 at 623 m - Siberian solar radio telescope - ccpt (Smolikov, J. and others "Siberian solar radio telescope", In the book. "Research on Geomagnetism, Aeronomy and Solar physics"), Science, 1990, vol. 91, S. 146).The method is implemented as follows. Register the image of the Sun, produce the selection of a local source, receive spatial spectrum of the image of the source, then use Fu the images is plotted in the coordinate system of the guides of the cosines of the direction interferometer. In this case, the phase distortion in the antenna-feeder path appear parallel to the axes of the spectrum of spatial frequencies of the interferometers ccpt (East-West, North-South). Small angular sizes of a local source is required for the spectrum of spatial frequencies of this source was present significant responses at frequencies not less than the highest spatial frequency of the interferometer. When this check is performed in the T-shaped tool mode (Grechnev centuries , crackles T. A. "the dependence of the response of the interferometer ccpt from observation conditions and parameters of the receiving system", In the book. "Research on Geomagnetism, Aeronomy and Solar physics", Novosibirsk, . Science, 1994, vol. 102, S. 232). In this mode excludes mutual influence of the opposite shoulder of the tool. In the spectrum from them there are components on the same frequency, but with different signs of the imaginary part. The duration of implementation is determined by the required signal-to-noise ratio for weak sources, respectively the reduction of measurement errors. When a 20-30 minute recording this ratio is improved by 3 times in comparison with the signal-to-noise ratio for the image obtained in one period of the interference pattern of integration of the source is equal to the product of the Fourier image of the pattern tool and the Fourier image of the image source, and the pattern is determined by the Fourier transform of the amplitude-phase distribution in the aperture of the instrument.The effectiveness of the described method have been successfully used in obtaining two-dimensional maps on the STDB, representing a 256-element cross interferometer, operating at a frequency of 5730 MHz (Smolikov and others ). The use of this method is to reduce the mean square error of the phase of the signal distribution on the aperture to 5-6 degrees, which is equivalent to 1 mm on the bases 623 M. This, in turn, reduces the error analysis of the structure of images of active regions and flares on the Sun.Sources of information
1. Krissinel B. B. "Methods of phasing and beam arrays microwave range" - In the book. "Research on Geomagnetism, Aeronomy and Solar physics"), Nauka, 1977, vol. 42, S. 142.2. Grechnev centuries , crackles T. A. "the dependence of the response of the interferometer ccpt from observation conditions and parameters of the receiving system". In kN. "Research on Geomagnetism, Aeronomy and Solar physics", Novosibirsk, Science, 1994, vol. 102, S. 232.3. Smolkov, J. and others "Siberian solar radio telescope", In the book. "Research on Geomagnetism, Aeronomy and physics is cobrasnake interferometer, characterized in that the recorded image of the Sun, choose it local source of small sizes of the order of the pattern and determine the image spectrum of this source, then from the spectrum get the phase distribution across the aperture for 20-30 min in parallel to the observations of the Sun.
FIELD: radio engineering.
SUBSTANCE: device for measuring effective scattering cross-section of radio-location objects has receiving-transmitting unit, registrar, stand mounted for rotation and provided with fixing unit which is used for mounting test object oriented in such a manner that normal to flat front of electromagnet wave radiated by receiving-transmitting unit belongs to preset plane of rotation of object. Precision inspection of measurement of angular diagram of effective scattering cross-section of objects provided due to the fact that radio-transparent envelope is rigidly fixed on the surface of object in parallel with preset plane of rotation of object. Radio-transparent envelope is made in form of thin straight cylinder of preset size. Cavity of envelope is partially filled with e4lectrically conducting liquid. Measured maximal level of effective scattering cross-section of main lobe of radio-transparent cylinder allows to find angle of inclination of plane of rotation of object.
EFFECT: improved precision of inspection.
FIELD: aerial engineering.
SUBSTANCE: cavity of radio-transparent envelope which has to be model of tested object is partially filled with electrically conducting liquid. Level of liquid is controlled by piston pump and measured by level meter. Radio-transparent cavity has a shape of circular cylinder with preset sizes which shape allows reproduce "selection" of standard reflectors in form of circular cylinders at smooth change in level of electrically conducting liquid. Values of dissipation effective areas of the cylinders can be calculated with high precision. Radio-transparent envelope can have shape of cylindrical pipe.
EFFECT: simplified process of test calibration; widened range of measured values of dissipation effective area.
3 cl, 8 dwg
SUBSTANCE: viewfinder is disposed at specific distance from mechanical axis of aerial. Viewfinder is tightly connected with antenna aperture plane. Optical axis of viewfinder is directed in parallel to mechanical axis of aerial. Then electrical axis of aerial is guided to phase center of ancillary aerial which is disposed together with geodetic mark onto post. Optical axis of viewfinder is guided onto geodetic mark. Geodetic mark is tied to angular position detectors and stays apart from phase center of ancillary aerial for distance being equal to shift of viewfinder from mechanical axis of aerial to the plane of normal optical axis of viewfinder. Optical axis of viewfinder is guided onto center of aperture of ancillary aerial. Difference in coordinates is determined by angle of location of initial and final position of viewfinder optical axis. Sword is turned around axis being perpendicular to plane of sword and crossing center of ancillary aerial aperture by angle determined by the relation given in the description of the invention. Electrical axis of aerial is guided onto phase center of ancillary aerial and optical axis of viewfinder is guided onto geodetic mark.
EFFECT: improved precision of adjustment.
FIELD: radio measurement engineering.
SUBSTANCE: method can be used for tuning and inspecting code on-board detectors of transportation vehicle automatic identification telemetric system. Section of reference aerial is calibrated in echo-free reference chamber inside which non-modulated oscillations are excited by connecting load in form of light-emitting diode cell to reference aerial. Fiber-optic section provided with light-receiving device and pre-calibrated indicator are also connected to reference aerial. Tested aerial is placed into the field induced by oscillator and measuring aerial inside working echo-free medium. The field is pre-calibrated by attenuator corresponding to readings of indicator of the reference aerial placed in the field before placing tested aerial inside the field.
EFFECT: improved truth of measurement; improved reliability of operation.
FIELD: adjustment of electrical axis of antenna.
SUBSTANCE: method includes using auxiliary antenna and geodesic mark, linked with indicators of angular position of target antenna, viewfinder is positioned near opening of subject antenna, rigidly linked to opening plane of subject antenna. Flat metallic screen is inserted, to which emission from auxiliary antenna is directed, auxiliary antenna and geodesic mark as light source are positioned behind subject antenna at remote zone distance. Electric axis of subject antenna is directed using its rotation gear according to one of minimum methods to phase center of auxiliary antenna, screen is mounted so, that beams, falling o it from auxiliary antenna and geodesic mark, were reflected respectively to whole plane of opening of target antenna and inlet eye of viewfinder. Angular deflection of optical axis of viewfinder from direction to center of image of geodesic mark on screen determines adjustment of target antenna.
EFFECT: higher precision.
FIELD: aerial measurement.
SUBSTANCE: method can be used for measurement of directional pattern of phased arrays and detection of damaged channels of phase array when using standard equipment of radar installations which have phased arrays as a part of equipment. Super-high frequency control signal is generated and irradiated by motionless probe at the direction of phased array. Control signal is received by phased array at alternate modulation of signal phase of each channel of phased array and signal is subject to coherent conversion to video frequency followed by selection of quadrature-phase component. Channel is switched to any phase state only once and at any phase state of the channel the analog signal is transformed into digital one K times (value of K varies from 100 to 10000 and higher depending on number of channels). Digital indications are rearranged in such a way that phase of signal of commutated channel in adjacent readings would differ for discrete value of switching of channel's phase. Signal spectrum is calculated. All the spectral components are reduced excluding components of useful signal which number equals to number of phase states of channel. Spectral component corresponding to zero frequency is reduced to zero. Fourier anti-transform is calculated. The sequence calculated has to represent complex excitement amplitudes for any phase state of channel.
EFFECT: improved precision of measurement; reduced time of measurement.
2 dwg, I tbl
FIELD: measurement engineering; amplitude-phase aerial measurements.
SUBSTANCE: device for measurement amplitude-phase field distribution in receiving aerial aperture has super-high frequency generator. Output of the generator is connected with measuring probe and with first input of amplitude-phase meter. Output of the latter is connected with first input of data collection and control device. First input of the latter is connected with first input of first computational unit intended for memorizing measured relations of signal amplitudes and phases and for computing amplitude-phase distribution. Device for measurement amplitude-phase distribution has turn unit being mechanically connected with tested aerial which has output connected with second input of amplitude-phase meter. Data collection and control unit serves for forming and outputting control commands to turn unit and for controlling measurement device in total. Device also has second computational unit intended for computing coordinates of points of measurement of tested aerial's transmission factor vector correspondingly to optimal spatial structure of measurement and memory unit intended for storing information on spatial configuration of the aerial. Output of second computational unit is connected with second input of information collection and control unit and with second input of first computational unit. Output of memory unit is connected with input of second computational unit and with third input of first computational unit. Memory unit is mounted onto tested aerial.
EFFECT: improved precision of measurement.
FIELD: equipment for antenna measurements, primarily, satellite antennas.
SUBSTANCE: echo-less chamber, including reflector, receiving technological antenna and system of transmitting cone-shaped irradiators, is provided with system of pulling and adjusting ropes made of resilient radio-transparent material. On aforementioned ropes, receiving technological antenna is held with possible movement by adjusting length of ropes, optical axis of antenna is directed perpendicularly to phase front of electromagnetic wave reflected by reflector. System of transmitting cone-shaped irradiators is connected to adjusting rope and held on a console, which is made of durable rigid radio-transparent material and held on the wall of echo-less chamber.
EFFECT: increased precision of reflector parameters measurements.
FIELD: radar engineering.
SUBSTANCE: installation can be used for measurement of radar characteristics (amplitude and phase diagrams) off dissipation for objects with different shapes. Radar compensation-type measurement installation with continuous radiation has diffuser, bed of diffuser, rotary unit, angle meter, reference signal generator, first attenuator, oriented de-coupler, matching transformer, second attenuator, double wave-guide T-bridge, load, transmitting aerial and receiving aerial. Unit for measuring difference in phases and level relation is introduced into installation additionally as well as control and processing unit, rotary unit control device and amplifier. Time of measurement is reduced due to complete automation of measurement of reverse dissipation process of real objects is provided.
EFFECT: reduced time of measurement; improved precision of measurement.