RU2014624C1 - Bed for measurement of electromagnetic field around object - Google Patents

Abstract

FIELD: aerial measurements. SUBSTANCE: azimuthal guide 2 is manufactured in the form of ring and elevation angle guide 1 is fabricated in the form of semi-ring and is put on azimuthal guide 2 for rotation along azimuth. First and third probes 4, 9 are mounted for movement over elevation angle guide 1. Sections of rectangular guide 3 are placed in plane of azimuthal guide 2. Second probe 5 is mounted for movement on rectangular guide 3. The latter can be manufactured in the form of telescopic rod. Second probe is set on it fixedly. EFFECT: expanded operational capabilities. 3 cl, 3 dwg

Description

 The invention relates to techniques for antenna measurements, in particular onboard antennas of aircraft (LA), and can be used to predict the electromagnetic compatibility of onboard electronic equipment (RES), as well as to determine the overall electromagnetic environment (EMO) around a full-scale measurement object, taking into account its influence conductive surface.

 The well-known stand of the company SCIENTIFIC - ATLANTA INC (USA) for determining the characteristics of the onboard antennas of full-scale aircraft objects (SCINTIFIC - ATLANTA Instrumentation Product Catalog. 1975. Photo attached). In this case, measurements of the characteristics of the onboard antennas, taking into account the conductive underlying surface of the aircraft, are made by the far-field method by rotating the object itself in limited rotation angles and when it is zoomed in on the rotary support device sequentially from different positions.

 As an analogue, an automated stand for measuring the characteristics of onboard antennas in the far zone in the conditions of a radio anechoic chamber can be noted.

 Obviously, the procedures for carrying out such measurements with full-scale objects are cumbersome, expensive and time consuming. At the same time, when the object is saturated with airborne RES, such measurements are inevitable. An important factor in measuring the electromagnetic characteristics of large-sized objects is the distance between the object and the auxiliary antenna on the tower. For measurements by the far zone method with an object size of several tens of meters, these distances can reach hundreds of meters, i.e., measurements are taken from anechoic chambers to open polygons. In this case, the object has to be lifted from the ground to reduce its influence.

 An alternative is measurements on large-scale models of aircraft objects, carried out at appropriate stands by the methods of the far and near zones. However, this significantly reduces the measurement accuracy, since it is impossible to achieve a complete geometric and electromagnetic similarity of the model with the original.

 Thus, the preferred option is to measure the characteristics of the antennas by the near-field method, and for natural full-scale objects.

 The closest methodically and constructively seems to be the stand described in the work of Adamyan R.M., Asatryan D.G., and Geruni S.P. "Measuring complex" Sphere-2 ", - In the book:" Antenna measurements. Abstracts of the Fourth All-Union Conference "Metrological Support for Antenna Measurements (VKAI-4), Yerevan, 1987, p.237. The stand provides measurements of fields and in general EMF around large-sized antennas, large-scale models of objects, as well as fragments of full-scale objects on a spherical surface in them near zone.

 However, the well-known stand is not well suited for measuring EMF around large full-scale objects due to the complexity of the procedure for installing them on a rotary stand and bringing it into rotation around the azimuth axis. In addition, the device in one measurement cycle provides the study of only the upper hemisphere around the object, while on a real aircraft, on-board antennas and other RES are also located in the lower part of the fuselage, for which they re-fix the object.

 The purpose of the invention is to simplify the measurement methodology and procedure while increasing their information content (angular measurement sector) and reducing the measurement time.

 This is achieved by the fact that in the stand for determining the electromagnetic environment around a full-scale object, consisting of its support and rotary device, a vertically mounted curved elevation guide and a measuring probe with the ability to move along it, the vertical elevation guide is made in mind of a semicircle on which it is mounted with the possibility of movement the first measuring probe, it itself is installed with the possibility of movement on a horizontally located azimuthal guide in the form of a full circle, while slewing the object is absent, and the test object is fixedly mounted within the space defined by the elevation and azimuth guide, arranged in the plane of the last rectilinear guide section and a second probe movably thereon.

 Instead of sections of straight guides, a radial guide can be installed with the possibility of periscopic change of length along the radius formed by the azimuthal guide, attached by the first end to the base of the elevated guide, and the second end to the wheel support, and the second measuring probe is fixed on it.

 In addition, in each of them a third measuring probe can be introduced, which is also mounted on a vertical angle guide rail with the possibility of movement.

 In FIG. 1 shows a functional diagram of the proposed stand; figure 2 is the same, an embodiment; figure 3 is the same embodiment.

 The stand contains a vertically mounted elevation guide 1, a horizontally mounted azimuthal guide 2, sections of straight guides 3, a first measuring probe 4, a second measuring probe 5, the test object 6 and radar absorbing material (RPM) 7.

 The stand works as follows. The vertical elevation guide 1, made in the form of a semicircle, is installed by two bases in a position taken as the initial one, on a horizontally located azimuthal guide 2. The first measuring probe 4 starts to run along the guide 1, describing the semicircle and measuring the amplitude and phase of the field in the given discrete points in the near zone around the object 6. The electric axis of the probe 4 is directed to the center of the synthesized spherical surface. Next, the guide 1 makes an azimuthal rotation along the guides 2 by a predetermined discrete angle and the distance of the measuring probe 4 is repeated in the opposite direction. The process is repeated until the guide 1 reaches the position corresponding to its half-turn in azimuth, counting from the starting point of measurement. In this position, the synthesis of the matrix of measured values of the amplitude-phase distribution (AFR) of the field in the near zone around the object 6 on a spherical surface is completed. The matrix can be subjected to appropriate mathematical processing to determine the characteristics of the field in the far zone of the object.

 Simultaneously with measurements in the upper hemisphere, a field is also measured in the lower half-space of an object using a flat surface scanning technique in its near zone. To do this, the second measuring probe 5 runs along sections of rectilinear guides 3, measuring the AFR field at given discrete points of the synthesized rectangular planar measurement matrix. Further, the matrix can be subjected to appropriate mathematical processing to determine the characteristics of the field in the far zone of the object. The electric axis of the probe 5 is directed vertically upward. To reduce the effect of rereflections, the surface under the object is forced by RPM.

 In contrast to figure 1, the stand contains a radial periscope guide 3 and a wheel support 8.

 The stand (figure 2) works as follows.

 In parallel with the movement of the first measuring probe 4 along the vertical elevation guide 1, the radial periscope guide 3 extends (moves in). It is fixed by the first (base) end to one of the supports of the vertical elevation guide 1, and the second (alternate) end is attached to the wheel support 8. The second measuring probe 5, the electric axis of which is directed vertically upward, is mounted on the thief end of the periscope guide 3 and during the radial movement of the probe 5 from the center of the circle formed by azimuthal guide 2 (or vice versa), the field is measured at given discrete points along the radius. Next, the vertical elevation guide 1, and with it the radial guide 3 attached to it, rotate at their predetermined discrete azimuth angle and the distance of the measuring probes 4 and 5 is repeated in the opposite direction. The process is repeated until the position of the guide 1 corresponding to the half-turn in azimuth is reached, counting from the starting point of measurement. In this position, both the synthesis of the upper hemispherical measuring matrix and the synthesis of a plane-polar measuring matrix corresponding to the lower half-space in the near zone of the object are completed. 6. Data processing on the plane-polar matrix is carried out by appropriate mathematical software.

 The stand (Fig. 3) contains an additional third measuring probe 9, also mounted on a vertical elevation guide 1 with the possibility of movement along it.

 The stand works as follows.

 In contrast to the work of the stand (see Fig. 2), the total scan length along the vertical elevation guide 1 is conditionally divided into two identical sectors (0o-90o and 91o-180o in elevation). The first measuring probe 4 performs its reverse runs in only one of the sectors of the guide 1, and the third measuring probe 9 - only in the second sector. The displacements of both probes 4 and 9 and the corresponding measurements of the AFR field occur in parallel in time, which reduces the time spent on scanning the upper spherical half-space and makes it comparable with the time spent on scanning the lower planar half-space.

 Thus, using various methods for determining the characteristics of an object in the far zone from the results of measuring AFR on a spherical and planar surfaces in its near zone, or spherical and plane-polar, it is possible to compile a complete EMO picture around the object, taking into account the influence of the conducting surface of the object. In this case, the use of time-parallel scanning gives a big gain in time. The proposed stand can be mounted directly at aerodromes, at the parking lot of aircraft or in hangars equipped with RPM, and its usual conditions, i.e. fulfilling the conditions of non-destructive testing during measurements. At the same time, the radio-measuring equipment can be placed in a mobile laboratory.

Claims (3)

 1. A STAND FOR MEASURING AN ELECTROMAGNETIC FIELD AROUND THE OBJECT, comprising a first probe mounted to move on an elevated rail made in the shape of a half-ring, characterized in that, in order to simplify the measurements, an azimuthal rail made in the form of a ring is inserted and installed in it the plane of the section of the rectilinear rail on which the introduced second probe is mounted with the possibility of movement, the elevation rail is mounted on the azimuthal rail with the possibility of azimuthal ascheniya.  2. The stand according to claim 1, characterized in that the straight guide is made in the form of a telescopic rod placed radially and fixed at one end on the basis of the elevation guide, and the other on the introduced wheel support, the second probe being fixed on the telescopic rod.  3. The stand according to claims 1 and 2, characterized in that a third probe is introduced, which is mounted on an elevated rail with the possibility of movement.

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