JPS59151502A - Adaptive antenna device - Google Patents

Abstract

PURPOSE:To improve the S/N by separating a desired wave by means of a polarized wave and suppressing a disturbing wave by means of a subtracting circuit and a correlation loop. CONSTITUTION:Outputs of antenna elements 50-53 receiving a polarized wave having a polarized plane orthogonal to the antenna elements are fed to an adder circuit 58. Outputs of antenna elements 54-57 are fed to subtracting circuits 59-61, the desired wave is reduced sufficiently by the polarized plane and the subtracting circuits and fed to correlating devices 65-67. Plural disturbing waves only are outputted from the subtracting circuits 59-61 and weighted at weighting circuits 62-64 by a suitable weight decided by the correlating devices and the disturbing waves inputted from the adder circuit 58 are cancelled by using a subtracting circuit 68.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention provides a method for automatically removing 42 interference waves in a radio wave environment in which a jammer exists (2), receiving only desired signal waves, and improving the signal-to-interference wave ratio. [Technical background of the invention and its problems] Figure 1 shows a conventional example of eliminating interference waves using 22 antenna elements.This is a cytrope canceller. This is the most representative method.

Now, suppose that the antenna elements (1) and (2) l= are input with a desired signal (6) and an interference wave (7).

Antenna element (2) (2) Attach an appropriate weight (4) to the generated interference wave (7), and then calculate the same amplitude and phase as the □ interference wave (7) that entered antenna element (1); Difference circuit (5)
This is a method of subtracting. This method is effective when the interference wave is sufficiently larger than the desired wave, but conversely, when the interference wave is smaller than the desired wave (2), it reduces the level of desired compensation (
2. It is not effective because it works. The reason for this is that in this method, the above weights are determined by the correlator (3) (2), and the output of the correlator (2) is determined by the input level (c) of the correlator (the input level of the two signals or interference waves). To be determined (according to 2.

In order to obtain the correlator output of only the interfering waves (==, the desired wave/suppression HL-c is added to the input (c) of the correlator so that only the interfering waves can be correlated.

Therefore, the methods shown in Figure 2 and Figure 3 are being considered.

Figure 2 (: In the system shown, a sum circuit a and a difference circuit are provided to calculate the sum and difference of the outputs of two antenna elements. When coming from the front direction of the array of element (1) and antenna element (2), if the lines connecting difference circuit I and antenna element (1) and antenna element (2) are the same length, the desired signal (6) This difference circuit I cancels each other out, resulting in a zero output.On the other hand, if the interference wave (power comes from a direction other than the front direction), the output of antenna element (1) and the output of antenna element (2) (there is a phase difference between the two) Therefore, the input (c) of the correlator (3) is only the interference wave.The weight (4) is used to suppress only the interference wave. (2 values can be set.

Figure 3 shows how the desired waves output from antenna elements (1) and (2) are suppressed using another correlation processing loop so that the input (c) of the correlator (3) becomes only the interference wave input. This is a method to do so. In this case, if the desired wave (6) is larger than the interference wave (7), the weight (al) of the correlation loop (to) operates on the desired wave (2) and acts (2) to eliminate the desired wave.

By the way, in the above method, it is assumed that the input (c) of the correlator can be completely made up of only interference waves, but this is not necessarily the case in actual hardware, and some desired waves leak in.

In a radio wave environment where the desired wave (6) is larger than the interference wave (7) (n, the correlation output of the desired wave in the correlator section (-) has a slight influence on the correlation output of the interference wave by V<2, and the weight (4) is the interference It is not a value for suppressing only waves and has an error.

Figure 4 shows the input signal-to-(interference + noise) ratio (SINR) and that of the output when the desired signal is noise at the receiver (Nirube 10 blades d, antenna spacing is 1 wavelength, and interference direction is 20 cm). Sa in the figure is the input of the correlator (= level of desired signal leaked in), and the receiver noise level is OdB. In Figure 4, when the interference wave is smaller than the desired signal, , Sa have a large influence, and if the leakage of Sa is large, the deterioration of the output SINH is large.

Usually, the difference circuit or correlation loop shown in Figs.
If it is B, then in FIG. 4, Sa corresponds to 30 to 10 dBζ2. For this reason, it is not possible to expect an improvement in the output 5INH.
It has its drawbacks.

[Purpose of the invention]

This invention was made in view of the drawbacks of the prior art described above, and even if a weaker interference wave than the desired signal arrives, the
It is an object of the present invention to provide an antenna device that can further improve the characteristics.

[Summary of the invention]

Generally, the polarization of the arriving desired wave is known and is determined to be, for example, horizontal or vertical polarization. Therefore, for purpose C2 of receiving the desired wave, an antenna capable of receiving the known polarization is used. If it is desired to suppress the desired wave, an antenna with polarization orthogonal to the antenna described above may be used.

On the other hand, interference waves rarely have the same polarization as the desired wave, and interference waves caused by intentional interference or natural phenomena often have polarization components other than the desired wave. Therefore, the antenna with the above-mentioned orthogonal polarization suppresses the desired signal, but cannot suppress the interfering wave, and outputs a certain level.This can be used in the method t' of FIGS. 2 and 3. In FIG. 2, the antenna element (1) of the difference circuit I,
(2) instead of input ζ:, antenna elements (1), (2)
Another set of antenna elements whose polarization planes are orthogonal to each other is used.

The same applies to Figure 3 Koji. As a result, the desired wave is separated by the polarization synchronization, and only the interfering wave is input to the correlator (3). If polarization separation alone is not sufficient to suppress the desired wave, the difference circuit aυ or correlation loop shown in Figures 2 and 3 can further suppress the desired wave (the effect of suppressing the desired wave is very high).
Two grow bigger.

[Effects of the Invention] As explained above (according to the present invention (2), the desired wave can be sufficiently suppressed by polarization separation, difference circuits and correlation loops (2),
As a result, as shown in FIG. 4, a significant improvement in the output 5INH can be expected since the 2Sa becomes sufficiently small.

[Embodiments of the invention]

FIG. 5 shows an embodiment when combined with a difference circuit. An antenna element (to) that receives the same polarization as the desired wave (6),
0 is connected to the sum circuit (to) 薯2. An antenna element cla that receives only polarized waves orthogonal to the polarization plane of the desired wave.

(to) is the difference circuit (to) (two are connected.

Since the antenna elements (to) and (to) receive the polarization orthogonal to the polarization of the desired wave, the desired wave signal may not be received at all or may be received at a very low level. The reception level of this desired wave is determined by the orthogonal polarization characteristics specific to the antenna element and the mechanical inclination of the antenna element with respect to the polarization plane (=
Normally, positive polarization (-5 to -30 dB for two
It is possible to obtain.

Furthermore, the desired wave can be lowered by the post-difference circuit c3!51 which performs polarization separation, and the desired wave as a whole can be -40 dB or less at the correlator input (c).

As mentioned above, by using two sets of antenna elements with polarized waves orthogonal to each other (2), Sa shown in Fig. 4 can be made sufficiently small, and the output 5I can be used.
It becomes possible to improve NR.

Although two antenna elements are used in the embodiment shown in FIG. interference waves can be suppressed.

FIG. 6 shows two examples of this kind.

5(m-63) is an antenna element that receives the polarization of the desired signal (polarization that matches the two), and (b) to (5?) are antenna elements that receive polarization that has a polarization plane orthogonal to the antenna element. The outputs of the antenna elements on the sides are routed between the summation circuits (= guided.
υ(=guided) The desired wave becomes sufficiently low by the polarization plane and the difference circuit, and is guided to the correlator (to) ~ (67) l2. Only the multiple interference waves are output from the difference circuit (5ω~@〃) However, a suitable weight is added by the weight determined by the correlator (64 to (641'), and the interference wave input from the sum circuit group is canceled by the difference circuit H-=.

In addition, the type of antenna element, the method of the differential circuit, etc. may be selected depending on the type of antenna element or system.

The present invention can be implemented with various modifications without departing from the gist thereof.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the outline of an adaptive antenna for suppressing interference waves, and FIGS. 2 and 3 are diagrams for explaining a conventional adaptive antenna system having a device for removing desired waves. Figure 4 shows the relationship between the input signal-to-(interference wave + noise) ratio and the output signal-to-(interference wave + noise) ratio, using the desired signal level leaking into the correlator as a parameter, and Figure 5. 6 is a diagram showing the configuration of an antenna device according to one embodiment of the present invention, and FIG. 6 is a diagram showing the configuration of an antenna device according to another embodiment of the present invention. 31 is an antenna element capable of receiving the same polarization as the desired incoming signal wave, 32.33 is an antenna element orthogonal to the above antenna element, A sum circuit, 35 is a difference circuit, A is a difference circuit,
37 is a weighting device, a correlation device is a correlation device, and 39 is a system output. Also, 50.51.52.53 are antennas with the same polarization as the desired signal wave, 54.55.56.57 are antennas with polarization orthogonal to the above, 58 is a sum circuit, and 59°ω
, 61 is a difference circuit, 62, 63.64 is a weighting device, 65
, 66 and 67 are correlators, and 68 is a difference circuit. Agent: Patent Attorney Noriyuki Chika (and 1 other person) No. 4
Figure-30-10-400In? 0. 302 (force f1
4 wishes'l voice 1 (-i harm ten words) yo J: (dB)th
6 Figure

Claims (1)

[Claims] a plurality of first antenna elements that receive the same polarization as the incoming signal wave, a summation circuit that sums the outputs of these antenna elements, and a plurality of second antennas that can receive the polarization that is orthogonal to the first antenna element. a plurality of differential correlation circuits that take the difference between the outputs of the antenna element and the second antenna element; a correlator 1 weighting circuit whose inputs are the outputs of the sum circuit and the difference circuit; - an adaptive antenna device comprising: