JPH0352018Y2 - - Google Patents

Description

[Detailed explanation of the invention] [Industrial application field] This invention is applicable to buoys, FRP ships, wooden ships, yachts,
This invention relates to an octahedral corner reflector used to enable radar to detect life rafts and the like from a long distance.

[Conventional technology]

The reflection characteristics of the octahedral corner reflector in the direction of incidence of the radar beam are a combination of the characteristics of the square corner reflectors shown in Figure 2, and the reflection characteristics in the direction of incidence on the horizontal plane are called radar effective reflections. Expressed in terms of cross-sectional area, when one side L of the square corner reflector in FIGS. 2 and 3 is 14 cm, the characteristics shown in FIG. 4 were obtained by actual measurements for X-band 9375 MHz radar radio waves.

[Problem that the invention attempts to solve]

The reflection characteristics of the conventional octahedral corner reflector in the direction of incidence on the horizontal plane are relatively sharp, as shown in Figure 4, and the r.
The radar effective reflection cross section of stu reaches approximately 10 ^m2 , but the practical minimum radar effective reflection cross section is
There was a problem in that there were four parts, w, x, y, and z, where the continuous width of the so-called dead zone that did not reach the 1.5 m ² level was approximately 24° to 30°.

[Means for solving problems]

Therefore, the present invention is based on the apex a of the square radio wave reflecting plate A.
When the octahedral corner reflector is installed in space so that the apex b, which is symmetrical with respect to the center point O, is at the highest position and the apex b is at the lowest position, the three orthogonal axes of each of the eight square corner reflectors At the ends of the horizontal axes E and F, the respective shaft ends G and
A right-angled triangular radio wave reflecting plate with H as the apex is installed parallel to the other two orthogonal axes of the square corner reflector.

[Effect]

The reflection characteristics of the square corner reflector in FIG. 2, which is made up of three mutually perpendicular planes, in the incident direction include _one reflection (1), two reflections ( ₂ ), and three reflections ( ₃ ) as shown in FIG. 6A. Particularly useful as a corner reflector is triple reflection, where the reflection characteristics are not steep.In this case, the directional characteristic, that is, the radar effective reflection cross section, reaches its maximum value when the aperture of the square corner reflector is in contact with the incident radio wave. This is when the angle becomes a right angle, that is, when the center point O in FIG. 2 appears to be the center of the aperture.

By newly providing a right-angled triangular radio wave reflecting plate according to the present invention, for example, as shown in Fig. 6b,
4 or more multiple reflections such as ₄ are added, and this reflection leads to a significant reduction in the dead zone, especially in the direction of the conventional dead zone.

〔Example〕

Fig. 1 shows an explanatory diagram of one embodiment of the present invention, and Fig. 5 shows a horizontal radar of an octahedral corner reflector having the shape shown in Fig. 1 provided with a right-angled triangular radio wave reflecting plate according to the present invention. The actual measured value of the effective reflection cross section is shown. The L dimension in Figure 1 was 14 cm, the same as in Figure 3, and the dimensions of the two sides that sandwiched the right angle of the right triangle were 11.5 cm in this case. This dimension is 5
11.5 cm, although it can be considered from about 14 cm to 11.5 cm.
A moderate amount is best. Comparing this result with the one in Figure 4, the continuous width of the dead band is from 7° to
The angle was improved by about 1/3 to about 11°, clearly demonstrating the remarkable effects of the present invention.

FIG. 7 shows another embodiment. Of the eight square reflectors, only the four that have the maximum effective radar reflection cross section in the horizontal direction are equipped with the right-angled triangular radio wave reflector of the present invention. This is fine if you use it.

[Effect of idea]

This idea makes it possible to detect buoys, main ships, yachts, life rafts, etc. from a long distance using radar. This is related to improving the dead zone of octahedral corner reflectors, and by installing right-angled triangular radio wave reflecting plates at the horizontal axis ends of four square corner reflectors that have the maximum radar reflection cross section in the horizontal direction, it is possible to improve the dead zone in the horizontal direction. Reduce the bandwidth and also reduce the remaining 4
A similar right-angled triangular radio wave reflecting plate is provided at the horizontal axis end of a square corner reflector that mainly controls vertical characteristics, thereby reducing the dead band in the vertical direction.

Furthermore, it is known that the performance of a corner reflector is greatly related to the accuracy of the perpendicularity between orthogonal planes, and this right-angled triangular radio wave reflector also has the effect of strengthening the perpendicularity, and is effective in this respect. is also large. There are octahedral corner reflectors that can be assembled or expanded, but in these cases it is particularly difficult to maintain the squareness, and the dead zone tends to become large. The effect of the board is particularly large.

[Brief explanation of drawings]

Fig. 1 is a perspective view of an octahedral corner reflector according to the present invention, Fig. 2 is a perspective view of a square corner reflector, Fig. 3 is a perspective view of a conventional octahedral corner reflector, and Fig. 4 is a perspective view of a conventional octahedral corner reflector. Horizontal radar effective reflection cross section of octahedral corner reflector,
Figure 5 is a diagram of the effective horizontal radar reflection cross-section of the octahedral corner reflector according to the present invention, and Figure 6 is a diagram of the horizontal radar effective reflection cross section of the octahedral corner reflector according to the present invention.
In the explanatory diagrams of the case of reflection in the incident direction, Figure 6a shows the case of a conventional square corner reflector, and Figure 6b shows an example of newly added reflection in the case of the present invention.
FIG. 7 shows another embodiment of the present invention. In the figure, A, B, C...square radio wave reflector, E,
F...horizontal axis, G, H...horizontal axis end, O...center point, a...highest point, b...lowest point.

Claims (1)

[Scope of utility model registration request] In an octahedral corner reflector formed by making three square radio wave reflecting plates A, B, and C orthogonal to each other at a center point O to constitute eight square corner reflectors, the square radio wave reflecting plate A
In such a way that vertex a is at the highest position, and vertex b, which is symmetrical to it with respect to the center point O, is at the lowest position.
When the octahedral corner reflector is installed in a space, the axial ends G and H of the horizontal axes E and F of the three orthogonal axes of each of the eight square corner reflectors are placed at the apex. An octahedral corner reflector in which a right-angled triangular radio wave reflecting plate is installed parallel to the other two orthogonal axes of the square corner reflector.