JPH02161375A - Side lobe canceller - Google Patents

Abstract

PURPOSE:To improve the unnecessary wave suppressing performance by allowing a directional auxiliary antenna in the unnecessary wave incident direction. CONSTITUTION:An unnecessary wave which is made incident from a side lobe of a main antenna (A1) 1 is received and processed by a receiving circuit 3, and thereafter, inputted to a CSLC (side lobe canceller) circuit 100. On the other hand, a directional auxiliary antenna (A2) 2 is direction to an unnecessary wave incident azimuth by an antenna driving circuit 10 which operates, based on a manual azimuth designating signal, and an unnecessary wave which is made incident is received and processed by the receiving circuit and inputted to the circuit 100. The unnecessary wave from A1 passes through a subtracter 4 and made incident on a multiplier 5, the unnecessary wave from A2 is inputted to the multiplier 5, both the unnecessary waves are multiplied and inputted to a loop filter 6, and a correlation component of the unnecessary wave which is made incident from A1 and a reference signal to the unnecessary wave from A2 is extracted. Its component passes through an amplifier 7 and aligned with the phase and the amplitude of the unnecessary wave from A1 by the reference signal from A2 by a multiplier 8, and thereafter, subtracted 4 from the unnecessary wave from A1.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention provides a sidelobe canceller (hereinafter referred to as C3LC).
The present invention relates in particular to improvements in its unnecessary wave suppression performance.

[Conventional technology]

Unwanted radio waves such as interference waves are often incident on radar receivers through side lobes. In order to suppress these unnecessary radio waves, the correlation component between the received signal of unnecessary radio waves incident from the side lobe of the main antenna and the reference signal for the unnecessary radio waves received from the auxiliary antenna is extracted, and the unnecessary radio waves in the received signal from the main antenna are extracted. A sidelobe canceller is used that suppresses unnecessary wave components by estimating radio wave components and subtracting them from the signal received by the main antenna.

A system diagram of a conventional system related to this type of system is shown in FIG. 3, and FIG. 4 is a diagram for explaining its operation.

In Fig. 3, 1 indicates the main antenna and 2 indicates the auxiliary antenna.The received signal received by the main antenna 1 is received and processed by the receiving circuit 3, and then passes through the subtracter 4 and is input to the multiplier (1) 5. . On the other hand, the received signal received by the auxiliary antenna 2 is
After being received and processed by the receiving circuit 3, the signals are input to a multiplier (1) 5 and a multiplier (2) 8, respectively.

The output of the multiplier (1) 5 is input to a loop filter 6 to extract a desired correlation signal. The desired correlation signal is amplified by an amplifier 7 and input to a multiplier (2) 8.

A multiplier (2) 8 multiplies the signal after the auxiliary antenna reception processing and the desired signal, and inputs the result to the subtracter 4. In this configuration, the loop from the subtracter 4 through the multiplier (1) 5 and back to the subtracter 4 is called a correlation loop, and a circuit having this correlation loop is called a C3LC circuit 100.

Next, the operation will be explained. Unwanted waves incident from the side lobes of the main antenna 1 are received and processed by a receiving circuit 3 and then passed through a subtracter 4 and inputted into a multiplier (1) 5. One signal, the unnecessary wave incident from the omnidirectional auxiliary antenna 2, is received by the receiving circuit 3 and then sent to the multiplier (1).
5 is input. FIG. 4 shows the unnecessary wave input relationship between the main antenna pattern and the auxiliary antenna pattern. Multiplier (1)
5, unnecessary waves from each antenna are multiplied and outputted to the loop filter 6 as a multiplication output.

The multiplier (1) 5 and the loop filter 6 extract the correlation component between the unnecessary wave incident from the side rope of the main antenna 1 and the reference signal for the unnecessary wave received from the auxiliary antenna 2.

This correlation component is amplified by an amplifier 7 having a predetermined loop gain and inputted to a multiplier (2) 8.
One input of 8 is a reference signal of an unnecessary wave after receiving processing from the auxiliary antenna 2. This reference signal is sent to the multiplier (2)
8, the phase and amplitude are matched to the unnecessary waves from the main antenna 1. Thereafter, it is output to the subtracter 4, and the correlated component is subtracted from the received signal of the main antenna 1 as an unnecessary wave incident from the side rope of the main antenna 1.

The output of the subtracter 4 passes through the multiplier (1) 5 again and returns to the subtracter 4, forming a correlation loop.

[Problem to be solved by the invention]

Since the conventional C3LC is configured as described above,
Compared to a directional antenna, the gain of an omnidirectional auxiliary antenna is lower, and gain and phase fluctuations occur depending on the orientation. This causes a problem in that the loop gain of the C3LC decreases and the unnecessary wave suppression ratio of the C3LC decreases due to disturbances due to gain and phase fluctuations.

This invention was made to solve the above-mentioned problems, and it provides a side rope canceller that can improve the unnecessary wave suppression performance of C3LC by directing the directional auxiliary antenna in the unnecessary wave incident direction. The purpose is to provide.

[Means to solve the problem]

In the sidelobe canceller according to the present invention, the auxiliary antenna is a directional antenna, and the auxiliary antenna is manually or automatically directed in the direction of incidence of unnecessary radio waves.

[Effect]

In this invention, the auxiliary antenna is a directional antenna, and is directed in the unnecessary wave incident direction by the antenna drive circuit based on a manual direction designation signal or the like.

At this time, the auxiliary antenna, which is a directional antenna, has a higher antenna gain (compared to the omnidirectional antenna) and a reference signal with less fluctuation can be obtained, thereby improving the unnecessary wave suppression performance of C3LC.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

In Figure 1, the same symbols as in Figure 3 indicate the same things,
10 is an antenna drive circuit that drives the directional auxiliary antenna 2 based on the manual direction designation signal.

Next, the operation will be explained. Unwanted waves incident from the side lobes of the main antenna 1 are received and processed by the receiving circuit 3 and then input to the C3LC circuit 100. The one-way directional auxiliary antenna 2 is directed in the unnecessary wave incident direction by the antenna drive circuit 10 which operates based on a manual direction designation signal, and has the antenna pattern relationship shown in FIG. Unwanted waves incident on the auxiliary antenna 2 are received and processed by the receiving circuit 3 and sent to C5.
It is input to the LC circuit 100. The C3LC circuit 100 performs the same operation as the conventional one and suppresses unnecessary waves.

In the above embodiment, the antenna drive circuit 10 directs the auxiliary antenna 2 in the unwanted wave incident direction based on the manual direction designation signal, but the second embodiment of the present invention shown in FIGS. 5 and 6 As shown in FIG.
1 may be provided at the output of the main antenna system receiving circuit 3 to automatically detect the unwanted wave incident direction and direct the auxiliary antenna 2. Although this increases the circuit scale compared to manual azimuth setting, it has the effect of improving the ability to follow moving unnecessary waves.

Further, in the above embodiment, the circuit configuration for one unnecessary wave was shown, but as in the third embodiment of the present invention shown in FIGS. circuit 3,
A plurality of antenna drive circuits 10 and C3LC circuits 100 are provided, and a manual direction designation signal 1 is separately provided for a plurality of unnecessary waves.
By directing the auxiliary antenna 2 according to ~n, a C3LC for a plurality of unnecessary waves can be configured, and the same effects as in the above embodiment can be achieved.

Further, in the third embodiment, which is the C3LC for the plurality of unnecessary waves, based on the manual direction designation signals 1 to n,
Although the antenna drive circuit 10 is configured to direct each auxiliary antenna 2 in the direction of incidence of unnecessary waves, Section 9.10
As in the fourth embodiment of the present invention shown in the figure, an unnecessary wave direction detection circuit 11 is additionally provided at the output of the main antenna system receiving circuit 3 to automatically detect the direction of incidence of unnecessary waves and Alternatively, the same effect as in the above embodiment can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, since the auxiliary antenna is made to have directivity and is manually or automatically directed in the direction of unnecessary waves, a stable reference signal can be obtained. This has the effect of improving the suppression performance of C3LC.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of a sidelobe canceller according to the first embodiment of the present invention, Fig. 2 is an explanatory diagram of its operation, Fig. 3 is a system diagram of a conventional sidelobe canceller, and Fig. 4 is its operation. Explanatory diagrams, Figures 5 and 6, Figures 7 and 8,
9 and 10 respectively show the second embodiment of the present invention. Third. It is a system diagram of a 4th example, and its operation|movement explanatory diagram. 1... Main antenna, 2... Auxiliary antenna, 3...
Receiving circuit, 4... Subtractor, 5... Multiplier (1), 6
... Loop filter, 7... Amplifier, 8... Multiplier (2), 10... Antenna drive circuit, 11... Unnecessary wave direction detection circuit, 20... Manual direction designation signal, 10
0...C3LC circuit. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (2)

[Claims] (1) The main antenna is equipped with a correlation loop that extracts a correlation component between a received signal of unnecessary radio waves such as interference waves incident from a side lobe of the main antenna and a reference signal for the above-mentioned unnecessary radio waves received from a separately provided auxiliary antenna. In the sidelobe canceller that suppresses unnecessary radio wave components by subtracting the extracted correlation component from the received signal of A side lobe that is characterized by being oriented according to specifications.
canceller. (2) Equipped with an unnecessary radio wave direction detection circuit that detects an unnecessary radio wave direction from the received signal of the main antenna, and instead of manually specifying the direction of incidence of the unnecessary radio waves, the directional auxiliary antenna detects the unnecessary radio wave direction. 2. The sidelobe canceller according to claim 1, wherein the sidelobe canceller automatically directs the unnecessary waves to the direction by a circuit.