JPH04198788A - Target detecting device - Google Patents

Abstract

PURPOSE:To reduce the size of a conventional device by using a main reflector common to two radio waves with different frequencies and an auxiliary reflector reflecting the radio wave with one frequency and permeating the radio wave with the other frequency. CONSTITUTION:When radio waves with a frequency A and a frequency B are fed, the incident radio wave with the frequency A is reflected by a main reflector 1 and further reflected by an auxiliary reflector 2 and focused at the position of a feed horn 3 quite similarly to when a normal Cassegrain antenna is used. The radio wave with the frequency B is reflected by the main reflector 1 and permeates the auxiliary reflector 2 and is focused at the position of a feed horn 4 quite similarly to when a normal parabolic antenna is used. The radio waves with different frequencies can be concurrently focused at separate positions. Two antenna systems are not required to be installed in parallel, and the size of a conventional device can be reduced to a half.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a target detection device such as a tracking radar, and particularly to a target detection device using two types of radio waves having different frequencies.

[Conventional technology]

Conventionally, this type of target detection device corresponds to two types of radio waves.
Detection was performed using two antenna systems. FIG. 4 is a schematic block diagram showing the configuration of an example of this target detection device. The target is detected by a Cassegrain antenna consisting of two systems of main reflector 1.11, sub-reflector 2.12, and feed horn 3.13 according to radio wave frequencies A and B, and a transmitter/receiver 5.6. The target detection signal from the transmitter/receiver 5.6 is input to the selection switching circuit 7.

This selection switching circuit 7 selects frequencies A and H according to a switching signal 8.
Either system is selected and the target comparison signal is output.

Although this example uses Cassegrain antennas for both antennas, the present invention is not particularly limited to this example.

[Problem that the invention seeks to solve]

However, the conventional target detection device described above uses two antenna systems, and both must be placed in parallel toward the target so that they do not block each other. The disadvantage is that the dimension in the width direction becomes twice as large.

Therefore, when there are restrictions on the size and shape of an on-board device, there is a problem that the diameter of the antenna cannot be used effectively.

An object of the present invention is to eliminate such conventional drawbacks and provide a target detection device whose width dimension can be reduced to 1/2 by arranging two antenna systems coaxially. .

[Means for solving problems]

The target detection device of the present invention includes an elliptical or parabolic main reflector that reflects parallel incident radio waves and radiated radio waves from a focal point, and a Cassegrain antenna that is provided opposite to this main reflector and has a predetermined frequency. a sub-reflector that reflects radio waves and transmits radio waves of a frequency different from the sub-reflector; a first feed horn that transmits and receives radio waves between the sub-reflector and is disposed in the center of the main reflector; a second feed horn disposed at the focal point of the reflector and transmitting and receiving radio waves to and from the main reflector, and a first transceiver transmitting and receiving signals to and from the first feed horn; A second transceiver that transmits and receives signals to and from the second feed horn, and a selection switching circuit that switches the received signals from each of the first and second transceivers using a predetermined selection signal. It is characterized by

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a schematic block diagram showing the configuration of an embodiment of the present invention.The main reflector 1 of this embodiment is made of a metal radio wave reflector, and the sub-reflector 2 is made of metal as shown in FIG. It is made of lattice 7. This sub-reflector 2 has a frequency of A
The width of the grid is set at three intervals so as to reflect the radio waves of frequency B and transmit the radio waves of frequency B.

The feed horn 3 radiates the transmission output of the frequency A from the transceiver 5, and also guides the received power of the input frequency A to the transceiver 5. The transceiver 5 outputs the transmission output of the frequency A to the feed horn 3, Further, the received power from the feed horn 3 is converted into a target detection signal and outputted to the selection switching circuit 7.

The feed horn 4 radiates the transmission output of the frequency B from the transceiver 6, and also guides the received power of the incident frequency B to the transceiver 6. The transceiver 6 outputs the transmission output of the frequency B to the feed horn 4, It also converts the received power from the feed horn 4 into a target detection signal and outputs it to the selection switching circuit.

The selection switching circuit 7 selects and outputs the output of either the transceiver 5 or the transceiver 6 according to the switching signal 8.

FIGS. 2(a) and 2(b) are schematic diagrams showing the incident paths of radio waves of frequency A and frequency B. FIG.

First, in FIG. 2(a), an incident radio wave of frequency A is reflected by the main reflector 1, further reflected by the sub-reflector 2, and focused at the position of the feed horn 3. That is,
This is done in exactly the same way as when using a normal Cassegrain antenna.

On the other hand, in FIG. 2(b), the incident radio wave of frequency B is reflected by the main reflector 1, transmitted through the sub-reflector 2, and focused on the feed horn 4. That is, it is performed in exactly the same way as when using a normal parabolic antenna. Therefore, radio waves with different frequencies can be focused on different positions at the same time.

[Effects of the Invention] As explained above, the present invention uses a main reflector that is common to two types of radio waves with different frequencies and a sub-reflector that reflects radio waves of one frequency and transmits radio waves of the other frequency. Since it is possible to simultaneously focus two types of radio waves with different values to different locations on the central axis of the antenna aperture, there is no need to arrange the antenna system in parallel, the dimensions can be reduced to 1/2 compared to conventional devices, and the frequency can be reduced. It becomes possible to realize a target detection device using two types of radio waves with different values.

As a result, even when there are restrictions on size and shape, such as on-board equipment, the antenna system does not have to be arranged in parallel, so the antenna diameter can be increased, which is particularly effective.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram showing the configuration of an embodiment of the present invention, FIGS. 2(a) and (b) are schematic diagrams showing the incident paths of the radio waves (frequency A and B) in FIG. 1, FIG. 3 is a perspective view showing an example of the sub-reflector shown in FIG. 1, and FIG. 4 is a schematic block diagram showing an example of the configuration of a conventional target detection device. 1.11... Main reflector, 2.12... Sub reflector, 3, 13... Feed horn A, 4... Feed horn B, 5... Transmitter/receiver A, 6... Transmitter/receiver B, 7...Selection switching circuit, 8...Switching signal, 9...
・Metal grid.

Claims (1)

[Claims] A parabolic main reflector that reflects parallel incident radio waves and radiated radio waves from a focal point, and a Cassegrain antenna that is installed opposite to this main reflector to reflect radio waves of a predetermined frequency and radio waves of a frequency different from this frequency. a sub-reflector that transmits radio waves; a first feed horn that transmits and receives radio waves between the sub-reflector and is disposed in the center of the main reflector; A second feed horn that transmits and receives radio waves between the first feed horn and a first transceiver that transmits and receives signals between the first feed horn and the second feed horn. What is claimed is: 1. A target detection device comprising: a second transceiver that transmits and receives signals; and a selection switching circuit that switches between received signals from the first and second transceivers using a predetermined selection signal.