JP2010243202A - Device for measuring cross section of radar reflection - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a device for measuring a cross section of radar reflection which facilitates manufacture of a support base, while preventing lowering of measuring accuracy of RCS of a real target. <P>SOLUTION: A screen 3 for radio wave shielding is disposed between a turntable 1 and a radar device 2. Besides, the screen 3 for radio wave shielding interrupts a transmitted radio wave 7 from a transmission antenna 8. Thereby the arrival of the transmitted radio wave 7 from the transmission antenna 8 at the turntable 1 is obstructed. Moreover, the screen 3 for radio wave shielding has first and second radio wave shielding plates 10 and 11. The first and second radio wave shielding plates 10 and 11 are formed of a metal material. The screen 3 for radio wave shielding has an edge line 12 formed by joining the mutual end parts of the first and second radio wave shielding plates 10 and 11. The edge line 12 is tilted in the direction of transmission of the transmitted radio wave 7 from the transmission antenna 8 to the turntable 1. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an apparatus for measuring a radar reflection cross section used in measurement of a radar cross section (hereinafter referred to as “RCS”).

  Usually, the RCS is measured by transmitting a radio wave from a transmission unit to a target and receiving the radio wave reflected by the target as a reflected wave at the reception unit. Therefore, the reflected wave from the support table that supports the target becomes noise in the RCS measurement, which decreases the measurement accuracy.

Conventionally, in order to prevent reception of reflected waves from the support base, a support base having a horizontal cross-sectional shape of the support base body has been proposed. The support base body is inclined with respect to the transmission direction of the radio wave from the transmission unit. Thereby, it is suppressed that the electromagnetic wave from a transmission part is reflected toward a receiving part from a support base main body. A rotating table or a mounting plate on which a target is placed is provided at the upper end of the support base body (for example, Patent Document 1).

  Conventionally, a support base in which the horizontal cross-sectional shape of the support base body is circular has also been proposed (for example, Non-Patent Document 1).

Japanese Patent Laid-Open No. 2004-221843

ORBIT / FR website [searched on December 15, 2008], Internet <URL: http: // www. orbitfr. com / Systems / RCS-Measurements. aspx # section-Images>

  However, in the conventional techniques as described above, since the restrictions on the shape are large, the load resistance is often reduced. Therefore, when the actual mass is large, the reduced model has to be used as a measurement target. As a result, the RCS of the actual product is obtained by converting the measurement result of the reduced model, and there is a problem that the measurement accuracy is lower than that in the case where the actual product is the measurement target.

  Moreover, in the support stand of the apparatus for RCS measurement shown by patent document 1, although the suppression of the reflected wave from a support stand main body can be aimed at, the suppression of the reception of the reflected wave from a turntable or a mounting plate is aimed at. I can't. Therefore, there is a problem that the RCS measurement accuracy is lowered.

  Furthermore, the conventional technology as described above has a problem that it takes time to manufacture the support base because the support base body is largely limited.

  The present invention has been made to solve the above-described problems, and provides a radar reflection cross-section measuring device that can easily manufacture a support base while preventing a decrease in RCS measurement accuracy. The purpose is to obtain.

  The radar reflection cross-section measuring apparatus according to the present invention includes a transmission unit that transmits radio waves to a target, and a reception unit that receives radio waves transmitted from the transmission unit and reflected by the target as reflected waves. A radar device, a support base for supporting a target, and a radio wave shielding partition that is arranged between the transmission unit and the support base and blocks radio waves from the transmission unit. A pair of radio wave shielding surfaces are provided which intersect at a common ridge line inclined with respect to the direction in which the radio waves from the pedestal are transmitted to the support base, and the distance between the ridge lines increases toward the support base.

  According to the radar reflection cross-section measuring device according to the present invention, a radio wave shielding partition that blocks radio waves from the transmitter is disposed between the transmitter and the support base. Since there is a pair of radio wave shielding surfaces that intersect at a common ridge line that is inclined with respect to the direction in which the radio waves from the unit are transmitted to the support base, and that are spaced closer to the support base from the ridge line, the reception unit It is possible to reduce the amount of the reflected wave traveling toward, and to reduce the reception of the reflected wave from other than the specimen as noise to the receiving unit. Accordingly, it is possible to prevent a decrease in the RCS measurement accuracy of the actual target object. In addition, since the support base body is formed in a cross-sectional ship shape or a circular cross section, it is not necessary to incline with respect to the vertical direction, so the restrictions on the shape of the support base body can be reduced and the support base can be easily manufactured. Can be done.

It is a perspective view which shows the structure of the apparatus for RCS measurement by Embodiment 1 of this invention. It is a perspective view which expands and shows the electric wave shielding partition of FIG. It is a top view which shows a mode that the transmission electromagnetic wave from a transmission antenna is reflected in the electromagnetic wave shielding surface of the electric wave shielding partition of FIG. It is a perspective view which shows a mode that the transmission electromagnetic wave from a transmission antenna is reflected in the ridgeline of the electric wave shielding screen of FIG. The graph which shows the calculation result of the vertical polarization of the monostatic RCS in the case where the screen for shielding radio waves is arranged between the turntable and the radar device and in the case where the screen for shielding radio waves is not placed between the turntable and the radar device. is there. The graph which shows the calculation result of the horizontal polarization of the monostatic RCS in the case where the screen for shielding radio waves is arranged between the turntable and the radar device and in the case where the screen for shielding radio waves is not placed between the turntable and the radar device, respectively. is there. It is a graph which shows the calculation result of the vertical polarization of bistatic RCS at the time of arranging a screen for electric wave shielding between a turntable and a radar apparatus. It is a graph which shows the calculation result of the horizontal polarization of bistatic RCS at the time of arranging a screen for electric wave shielding between a turntable and a radar apparatus. It is a perspective view which shows the screen for electromagnetic wave shielding by Embodiment 2 of this invention. It is a perspective view which shows the screen for electromagnetic wave shielding by Embodiment 3 of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

Embodiment 1 FIG.
FIG. 1 is a perspective view showing a configuration of an RCS measurement apparatus according to Embodiment 1 of the present invention. In FIG. 1, the RCS measurement device includes a turntable 1 (support table), a radar device 2, and a radio wave shielding partition 3.

  The turntable 1 includes a turntable main body 4 and a specimen mounting plate 5 that is provided on the top of the turntable main body 4 and is rotatable about a rotation axis (not shown) along the vertical direction. Yes.

  A specimen (target) 6 that is an RCS measurement target is placed on the specimen mounting plate 5. The specimen 6 can be changed in direction (angle) by the rotation of the specimen mounting plate 5.

  The radar device 2 includes a transmission antenna 8 (transmission unit) that transmits a transmission radio wave 7 to the specimen 6, and a transmission radio wave 7 that is transmitted from the transmission antenna 8 and reflected by the specimen 6 as a reflected radio wave (reflection wave). As a receiving antenna 9 (receiving unit). The transmission antenna 8 and the reception antenna 9 are disposed adjacent to each other.

  The radar apparatus 2 measures the RCS of the specimen 6 by receiving the transmission radio wave 7 reflected by the specimen 6 by the receiving antenna 9 as a reflected radio wave. Here, the measurement performed by transmission / reception of the transmitting antenna 8 and the receiving antenna 9 adjacent to each other is referred to as “monostatic RCS measurement”. Therefore, the RCS measurement device in the present embodiment is a monostatic RCS measurement device.

  The radio wave shielding partition 3 is disposed between the turntable 1 and the radar apparatus 2. The radio wave shielding screen 3 blocks the transmission radio wave 7 from the transmission antenna 8. Thereby, arrival of the transmission radio wave 7 from the transmission antenna 8 to the turntable 1 is prevented.

  Further, the radio wave shielding partition 3 includes first and second radio wave shielding plates 10 and 11. The first and second radio wave shielding plates 10 and 11 are made of a metal material. In this example, the first and second radio wave shielding plates 10 and 11 are each a parallelogram metal plate.

  A ridgeline 12 is formed on the radio wave shielding partition 3 by joining the ends of the first and second radio wave shielding plates 10 and 11 together. The ridge line 12 is inclined with respect to the direction in which the transmission radio wave 7 from the transmission antenna 8 is transmitted to the turntable 1. The ridgeline 12 when the radio wave shielding screen 3 is viewed along the direction in which the transmission radio wave 7 is transmitted from the transmission antenna 8 extends in the vertical direction.

  The first radio wave shielding plate 10 is provided with a radio wave shielding surface 13, and the second radio wave shielding plate 11 is provided with a radio wave shielding surface 14. The radio wave shielding surfaces 13 and 14 intersect at the ridgeline 12.

  Further, the distance between the radio wave shielding surfaces 13 and 14 increases as the distance from the ridge line 12 to the turntable 1 increases. That is, the distance between the first and second radio wave shielding plates 10 and 11 increases as the distance from the ridge line 12 to the turntable 1 increases.

  FIG. 2 is an enlarged perspective view showing the radio wave shielding partition 3 of FIG. In the figure, a line segment (two-dot chain line in the figure) connecting each upper side of the first and second radio wave shielding plates 10, 11 and each upper side rear end (end on the side away from the ridgeline 12). The virtual upper surface 15 is an isosceles triangle having an apex angle α. Moreover, by the line segment (two-dot chain line in a figure) which connects between each lower side of the 1st and 2nd radio wave shielding boards 10 and 11, and each lower side rear end (end part on the side away from the ridgeline 12). When the surrounded surface is a virtual bottom surface 16, the virtual bottom surface 16 is an isosceles triangle having an apex angle α.

  The virtual top surface 15 and the virtual bottom surface 16 have the same shape. Further, the ridge line 12 is inclined by β with respect to a line perpendicular to the virtual upper surface 15 and the virtual bottom surface 16.

  The external shape of the radio wave shielding partition 3 is an oblique column having the virtual upper surface 15 and the virtual bottom surface 16 as the upper surface and the bottom surface.

  The height H of the radio wave shielding screen 3 is such that the turntable 1 is hidden when viewed from the transmission antenna 8. Further, the width W of the radio wave shielding screen 3 (the bottom sides of the virtual upper surface 15 and the virtual bottom surface 16) is such that the turntable 1 is hidden when viewed from the transmission antenna 8. However, the screen 3 for shielding radio waves as viewed from the transmitting antenna 8 is arranged avoiding the specimen 6.

  FIG. 3 is a plan view showing a state in which the transmission radio wave 7 from the transmission antenna 8 is reflected by the radio wave shielding surfaces 13 and 14 of the radio wave shielding screen 3 of FIG. As shown in FIG. 3, the radio wave shielding screen 3 is arranged at a position where an angle formed between each of the radio wave shielding surfaces 13 and 14 and a straight line along the transmission direction of the transmission antenna 8 is α / 2. . Thus, the transmitted radio wave 7 is reflected as the reflected radio wave 17 at the apex angle α with respect to the transmission direction of the transmitted radio wave 7 after reaching the radio wave shielding surfaces 13 and 14 of the radio wave shielding partition 3. Accordingly, the amount of the reflected radio wave 17 traveling toward the receiving antenna 9 is suppressed.

  FIG. 4 is a perspective view showing a state in which the transmission radio wave 7 from the transmission antenna 8 is reflected by the ridgeline 12 of the radio wave shielding partition 3 of FIG. As shown in FIG. 4, after the transmission radio wave 7 reaches the ridge line 12, the scattered radio wave 20 (in the direction of an arbitrary generatrix of a cone 19 (diffraction cone) having the incident point 18 as an apex and the ridge line 12 as an axis due to a diffraction phenomenon. Propagation as reflected wave). The angle formed by the ridgeline 12 and the generatrix of the cone 19 is (90−β) °.

  The upper end portion of the ridge line 12 is farther from the turntable 1 than the lower end portion of the ridge line 12. The upper end portion of the ridge line 12 is farther from the turntable 1 than the lower end portion of the ridge line 12. That is, the ridgeline 12 is inclined in a direction in which the distance from the turntable 1 is continuously separated from the lower end portion toward the upper end portion. Thereby, it is avoided that the scattered radio wave 20 caused by diffraction at the ridge line 12 travels toward the specimen 6. Thereby, the scattered radio wave 20 is prevented from being reflected by the specimen 6, and the scattered radio wave 20 is prevented from traveling toward the receiving antenna 9.

  In the first embodiment of the present invention, in order to confirm the effect of the radio wave shielding partition 3, the radio wave shielding partition 3 is arranged between the turntable 1 and the radar device 2, and the radio wave shielding partition 3 is replaced with the turntable 1 and The monostatic RCS was calculated when not arranged between the radar devices 2.

In the calculation, the shape of the turntable 1 is a cylinder. The diameter of the turntable 1 is 233λ ₀ (λ ₀ is a free space wavelength of the reference frequency f ₀ ), and the height is 200λ ₀ . Further, the radio wave shielding screen 3 was set to α = 70 °, β = 30 °, W = 233λ ₀ , and H = 200λ ₀ .

  FIG. 5 shows the monostatic RCS in the case where the radio wave shielding partition 3 is arranged between the turntable 1 and the radar device 2 and in the case where the radio wave shielding partition 3 is not arranged between the turntable 1 and the radar device 2. FIG. 6 is a graph showing the calculation result of the vertical polarization. FIG. 6 shows the case where the radio wave shielding partition 3 is arranged between the rotary table 1 and the radar device 2, and the radio wave shielding partition 3 is arranged between the rotary table 1 and the radar device 2. It is a graph which shows the calculation result of the horizontal polarization of monostatic RCS in each case with no.

In the graphs of FIGS. 5 and 6, the normalized frequency is shown on the horizontal axis, and the normalized RCS is shown on the vertical axis. Here, the normalized frequency is a value indicating the ratio (f / f ₀ ) of the frequency f to the predetermined reference frequency f ₀ . Further, the normalized RCS [dB] is the RCS [DBSM] in the case of calculating the frequency f as the reference frequency _{f 0} in the absence of radio wave shielding partition 3, the RCS [DBSM] when calculated at an arbitrary frequency It is a value indicating the difference between Therefore, the normalized RCS is 0 when the normalized frequency is 1.

As shown in FIGS. 5 and 6, compared with the case where the radio wave shielding partition 3 is not disposed between the rotary table 1 and the radar device 2 at the reference frequency f ₀ , the radio wave shielding partition 3 is set to the rotary table 1 and the radar device 2. The RCS of vertically polarized waves and horizontally polarized waves when arranged between them is reduced by 80 dB or more.

  As described above, according to the first embodiment, the radio wave shielding partition 3 for blocking the transmission radio wave 7 from the transmission antenna 8 with respect to the turntable 1 is disposed between the transmission antenna 8 and the turntable 1. The radio wave shielding screen 3 intersects with a common ridge line 12 inclined with respect to the direction in which the transmission radio wave 7 from the transmission antenna 8 is transmitted to the turntable 1, and the distance from each other becomes closer to the turntable 1 from the ridge line 12. Is provided with a pair of radio wave shielding surfaces 13 and 14, the amount of the reflected radio wave 17 traveling toward the receiving antenna 9 can be reduced, and the reflected radio wave 17 from other than the specimen 6 is received as noise by the receiving antenna. 9 can be reduced. Accordingly, it is possible to prevent a decrease in RCS measurement accuracy of the specimen 6. Further, since the transmission radio wave 7 for the turntable 1 is shielded by the radio wave shielding screen 3, the restriction on the shape of the turntable 1 can be reduced, and the turntable 1 can be easily manufactured.

  In the first embodiment, the present invention is applied to a radar reflection cross-section measuring device that performs monostatic RCS measurement. However, the present invention is applied to a transmitting antenna 8 and a receiving antenna 9 that are arranged at positions separated from each other. The present invention may be applied to a radar reflection cross-section measuring device for bistatic RCS measurement that measures RCS by transmitting and receiving radio waves (that is, performs bistatic RCS measurement).

  FIG. 7 is a graph showing the calculation result of the vertical polarization of the bistatic RCS when the radio wave shielding partition 3 is arranged between the turntable 1 and the radar device 2, and FIG. 5 is a graph showing a calculation result of horizontal polarization of a bistatic RCS when arranged between the radar device 2 and the radar device 2. 7 and 8, the horizontal axis represents the receiving antenna azimuth [°]. The vertical axis indicates normalized RCS [dB].

  In addition, the structure of the turntable 1 and the electric wave shielding partition 3 is the same as that of the turntable 1 and the electric wave shielding partition 3 when performing the above-described monostatic RCS measurement.

  As shown in FIGS. 7 and 8, if the receiving antenna 9 is arranged avoiding the reflection direction of the reflected radio wave 17 by the radio wave shielding surfaces 13 and 14 and the propagation direction of the scattered radio wave 20 by the ridgeline 12, the reflected radio wave 17 and the scattered radio wave are scattered. Since it is difficult to be affected by the radio wave 20, it is possible to suppress a decrease in accuracy of bistatic RCS measurement.

Embodiment 2. FIG.
FIG. 9 is a perspective view showing a radio wave shielding partition according to Embodiment 2 of the present invention. The radio wave shielding partition 21 has first and second radio wave shielding plates 22 and 23. Each of the first and second radio wave shielding plates 22 and 23 includes a base plate 24 and a conductive member 25 superimposed on the base plate 24. As the conductive member 25, for example, an aluminum foil or a conductive paint is used. The aluminum foil is stacked on the base plate 24 by being pasted, and the conductive paint is stacked on the base plate 24 by being applied.

  The first and second radio wave shielding plates 22 and 23 are made of a non-metallic material. Examples of non-metallic materials include FRP (Fiber Reinforced Plastics) and synthetic resins.

  The conductive member 25 of the first radio wave shielding plate 22 is provided with a radio wave shielding surface 26, and the conductive member 25 of the second radio wave shielding plate 23 is provided with a radio wave shielding surface 27. The radio wave shielding surfaces 26 and 27 intersect at the ridgeline 12. Other configurations are the same as those in the first embodiment.

  As described above, according to the second embodiment, the conductive member 25 on which the radio wave shielding surfaces 26 and 27 are formed is provided on each base plate 24. Therefore, the material of each base plate 24 is made of a lightweight resin or the like. It can be. Accordingly, it is possible to reduce the weight of the radio wave shielding partition 21 while preventing a decrease in the RCS measurement accuracy of the specimen 6.

Embodiment 3 FIG.
FIG. 10 is a perspective view showing a radio wave shielding partition according to Embodiment 3 of the present invention. The radio wave shielding partition 29 has first and second radio wave shielding plates 30 and 31.

  The first radio wave shielding plate 30 is provided with a radio wave shielding surface 32, and the second radio wave shielding plate 31 is provided with a radio wave shielding surface 33. The radio wave shielding surfaces 32 and 33 intersect at the ridgeline 12.

  A radio wave absorbing member 34 that absorbs the transmission radio wave 7 from the transmission antenna 8 is provided on each of the radio wave shielding surfaces 32 and 33. As the radio wave absorbing member 34, for example, a radio wave absorber or paint is used. The radio wave absorber is provided on the radio wave shielding surfaces 32 and 33 by being attached. The coating is provided on the radio wave shielding surfaces 32 and 33 by being applied. Other configurations are the same as those in the first embodiment.

  As described above, according to the third embodiment, since the radio wave absorbing member 34 that absorbs the transmission radio wave 7 from the transmission antenna 8 is provided on the radio wave shielding surfaces 32 and 33, the RCS measurement accuracy of the specimen 6 is measured. Can be prevented more reliably. Further, RCS measurement of a low RCS specimen such as a stealth machine is possible.

  In the third embodiment, the radio wave absorbing member 34 is provided on the radio wave shielding surfaces 32 and 33. However, the radio wave absorbing member 34 may be provided on the radio wave shielding surfaces 26 and 27 in the second embodiment.

  Further, in each of the above embodiments, one radio wave shielding partition is arranged between the turntable 1 and the radar apparatus 2, but a plurality of radio wave shielding partitions may be arranged along the transmission direction of the transmission radio wave. Good.

  Further, in each of the above embodiments, the radio wave shielding screen is formed using the first and second radio wave shielding plates. However, the radio wave shielding screen is formed using the first and second radio wave shielding plates as an integral member. May be formed.

  Furthermore, in each of the above embodiments, the end portions of the first and second radio wave shielding plates are joined together, but the end portions of the first and second radio wave shielding plates are merely in contact with each other. Good. In this case, a ridgeline is formed when the ends of the first and second radio wave shielding plates come into contact with each other.

  In each of the above embodiments, only the pair of side surfaces of the oblique prism formed by being surrounded by the five surfaces of the pair of side surfaces, the top surface, the bottom surface, and the back surface are used as the radio wave shielding surfaces of the radio wave shielding screen. In addition to the side surfaces, the top, bottom, and back surfaces may be used as the radio wave shielding surfaces of the radio wave shielding screen.

  DESCRIPTION OF SYMBOLS 1 Turntable (support stand), 2 Radar device, 3, 21, 29 Screen for shielding radio waves, 6 Specimen (target), 7 Transmitted radio wave, 8 Transmit antenna (transmitter), 9 Receive antenna (receiver), 10, 22, 30 1st radio wave shielding plate, 11, 23, 31 2nd radio wave shield plate, 12 ridge line, 13, 14, 26, 27, 32, 33 radio wave shielding surface, 17 reflected radio wave (reflected wave), 20 Scattered radio wave (reflected wave), 24 base plate, 25 conductive member, 34 radio wave absorbing member.

Claims (6)

A radar apparatus comprising: a transmission unit that transmits radio waves to a target; and a reception unit that receives radio waves transmitted from the transmission unit and reflected by the target as reflected waves;
A support base that supports the target, and a radio wave shielding screen that is disposed between the transmission section and the support base and blocks radio waves from the transmission section,
The radio wave shielding screen intersects with a common ridge line that is inclined with respect to the direction in which radio waves from the transmission unit are transmitted to the support base, and a pair whose distance increases as the distance from the ridge line becomes closer to the support base. An apparatus for measuring the cross section of a radar reflection, characterized in that a radio wave shielding surface is provided. The screen for shielding radio waves has a first radio wave shielding plate provided with one of the radio wave shielding surfaces and a second radio wave shielding plate provided with the other radio wave shielding surface,
The radar reflection cross-sectional area measuring device according to claim 1, wherein the ridge line is formed by aligning ends of the first and second radio wave shielding plates.   The radar reflection cross section measuring device according to claim 2, wherein the first and second radio wave shielding plates are made of a metal material.   3. Each of the first and second radio wave shielding plates includes a base plate and a conductive member that is superimposed on the base plate and has the radio wave shielding surface formed thereon. The radar reflection cross-sectional area measuring device described in 1.   3. The radar reflection cross-sectional area measuring device according to claim 2, wherein a radio wave absorbing member is provided on each of the radio wave shielding surfaces. The target is placed on the support base,
The ridgeline when the radio wave shielding screen is viewed along the direction in which radio waves are transmitted from the transmission unit extends in the vertical direction,
The radar reflection cross-section measuring apparatus according to any one of claims 1 to 5, wherein an upper end portion of the ridge line is further away from the support base than a lower end portion of the ridge line.

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