JPH02143184A - Laser device - Google Patents

Abstract

PURPOSE:To deteriorate the frequency measuring ability of a radio wave disturbing device by transmitting two sent radio waves simultaneously which have orthogonal planes of polarization after frequency modulation is imposed on only one radio wave. CONSTITUTION:A pulse-modulated carrier generated by an exciter 1 is distributed by a distributor 2 and one carrier is inputted to a composition device 4a. The two carriers which are put together by the composition device 4a are power-amplified by a power amplification part 5, and a radio wave which is not frequency-modulated by a diplexer 6 is passed through a circulator 7a and sent from a radar antenna 8b as horizontal polarized waves having orthogonal planes of polarization. Radar antennas 8a and 8b receive a reflected wave and a disturbing wave from a target at the same time, one is sent out to a composition device 4b through a circulator 7a, and the other is passed through a circulator 7b, demodulated by a demodulator 9 to the opposite characteristics from modulation characteristics, and sent out to the composition device 4b. In this case, the reflected wave and disturbing wave from the target differ in frequency, so they are easily discriminated and separated.

Description

[Detailed Description of the Invention] [Industrial Application] This invention is applicable to ECM (Electronic Warfare) of radar equipment in electronic warfare.
ECCM (Electric Counter Measures) and ECCM (Electric Counter Measures)
This is related to the operation of Counter Measures.

[Conventional technology]

FIG. 3 is a block diagram showing the operating principle of a conventional radar device in an electronic warfare environment. In FIG. 7m) is a circulator that switches between transmitting and receiving signals.

(8m) is the radar antenna of the radar device, α is the radar receiver, ■ is a radio wave jamming device that generates radio waves that interfere with the transmission signal of the radar device, and (21) is the receiving antenna.

(22) is an ESM (El
(24) is a pulse width measurement unit that measures the pulse width from the output of the ESM receiver (22), (25) is a Pulse repetition measuring section that measures the number of pulse repetitions from the interval of the pulse train.

(26) is a pulse amplitude gIR constant section that measures the power of the incoming radio wave, that is, the pulse amplitude, and (27) is the frequency measurement section (2).
31.

Pulse width measurement section (24), pulse repetition measurement section (25)
and a modulation section that estimates the specifications of the radar device from the measurement results of the pulse amplitude measurement section (26) and performs optimum generation control of interference waves. The transmitter that generates the interference (29) is the transmitting antenna that transmits the interference waves.

Next, the operation will be explained. The radar device is an exciter (
1) generates a pulse-modulated carrier wave.

The power amplification section (5) amplifies the power, and the circulator (7&
) and radiates into the air from the radar antenna (8a). On the other hand, the radio wave jamming device [phase] receives the radio waves transmitted by the radar device with the receiving antenna (21), further amplifies and detects them with the ESM receiver (22), and at the same time sends the radio waves to the frequency measuring unit (23).
The frequency of the radar device carrier wave is measured at Also, E
The detection output of the SM receiver (22) is sent to the pulse width measuring section (24).
), the pulse width, the number of pulse repetitions, and the pulse amplitude are measured by the pulse repetition measuring section (25) and the pulse amplitude measuring section (26), respectively. These measurement results are shown in the modulation section (2
7), the most effective modulation specifications as interference waves for the radar equipment in the same area are determined and sent to the jamming transmission II (281). According to the transmitting antenna (29
) towards the radar equipment. The radar antenna (8a) of the radar device receives the reflected wave of its own transmitted wave from the target and the interference wave of the radio wave jamming device at the same time, and sends it to the radar receiver 0■ via the circulator (7a).

Therefore, it becomes difficult to separate reflected waves and interference waves.

[Problem to be solved by the invention]

Conventional radar equipment is configured as described above, so
Wa radio wave jamming equipment can easily detect the radar's main specifications, such as frequency, pulse width, pulse repetition rate, and pulse amplitude, and if it transmits jamming waves with similar specifications, 2. The original radar reflected wave and the interference. Basically, it is not possible to separate the waves.

There were many disadvantages, such as the lack of countermeasures.

This invention was made to solve the above-mentioned problems, and its purpose is to prevent a radio wave jamming device from erroneously measuring a carrier wave among radar specifications.

[Top means to solve problems]

The radar device according to the present invention divides the transmission output into two parts, one of which is transmitted as is, and the other which is modulated with a specific frequency and transmitted with the plane of polarization orthogonal.

[For production]

In this invention, the two transmitted waves with orthogonal polarization planes cannot be separated by the receiving antenna of the radio wave jamming device, which normally does not have the directionality of the crawler wave (circular wave), but they can be separated independently by the radar device. It is possible to receive minutes.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. 1st
In the figure (1), (5), (7ml, (8m)
, scream and ■ are the same as in Figure 3, (2) is the exciter (1
) is a distribution M that divides the output of
h) is a combiner that combines two carrier waves or two received waves such as ζ; (6) is a diplexer that separates the carrier wave after power amplification into a frequency modulated wave and a non-frequency modulated wave;
(7bl is a circulator similar to (7a), (8
bl is a radar antenna that has the same structure as (8a) and is installed so that the plane of polarization is orthogonal to (81), and (9) is a demodulator that demodulates the frequency-modulated received wave with inverse characteristics. Fig. 2 is a timing diagram showing the time relationship of the transmitted radio waves, where 01) is the pulse waveform, @ is the frequency change characteristic within the pulse of the radio wave transmitted from the radar antenna (8a), and 0■ is the radar antenna (8b) is the frequency change characteristic within the pulse of the radio wave transmitted. In addition, in the same figure, the vertical axis direction indicates changes in radio field intensity or changes in frequency.
The horizontal axis direction represents the change in time.

Since one embodiment of the present invention is constructed as described above, the pulse-modulated carrier wave generated by the exciter (1) is distributed by the distributor (2), one directly to the combiner (4a) and the other to the combiner (4a). One side passes through the frequency modulation section (3) and then passes through the synthesizer (4a).
). Although any frequency modulation method may be used in the frequency modulation section (3), for the sake of explanation, a linear FM method known as a pulse compression technique will be taken as an example. This is because the frequency changes continuously and linearly within the pulse, as shown in frequency characteristic (3). Combined W (The two carrier waves combined in 411 are power amplified in the power amplification section (5), and then divided into two again by the diplexer (6) using the frequency difference. Radio waves that are not frequency modulated are sent to the circulator. (7a) and is transmitted from the radar antenna (8a) as a vertical wide wave, while the frequency-modulated radio wave is transmitted via the circulator (7b) from the radar antenna (8b) as a horizontally polarized wave with orthogonal polarization planes. Ro. Radio interference bag ra
m, the polarization characteristics of the waves transmitted by the radar device are unknown or undefined, so it is customary for the radio wave jamming device to receive circularly polarized waves. Therefore, L・-da antennas (8a) and (8b)
The radio waves transmitted from are simultaneously received by the radio wave jamming device@, and cannot be separated, so the radio waves from f, , f, to f2, and their combined various frequencies are generated as shown by two frequency change characteristics 0 and ■. As a result, it becomes impossible to measure the frequency. Hereinafter, the principle of generating interference waves with a radio wave jamming device is exactly the same as that of the prior art, but since the fundamental frequency is uncertain, the interference waves cannot be effective against radar equipment. Radar antenna (8a) and (8b)
Then, the reflected wave and the interference wave from the target are received simultaneously, and one is synthesized via the circulator (7a) (4b).
The other signal passes through the circulator (7b), is demodulated by the demodulator (9) according to a characteristic inverse to the modulation characteristic, and is sent to the combiner (4b). The two radio waves are combined by a combiner (
4b) and sent to the radar receiver.

As mentioned above, since the reflected waves from the target and the interference waves have different frequencies, they can be easily distinguished and separated.

In the above embodiment, the radar antenna (8&) is vertically polarized, and the radar antenna (8b) is horizontally polarized.

The same effect can be obtained even if this relationship is reversed.

〔Effect of the invention〕

As described above, according to the present invention, two MW waves with orthogonal polarization planes are transmitted at the same time, with one being subjected to frequency modulation and the other being subjected to frequency modulation.

The effect of degrading the frequency measurement ability of the radio wave jamming device can be expected, and the improvement of the ECCM ability of the radar device can be realized.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the operating principle of a radar device according to an embodiment of the present invention, and FIG. l! l is also 474
A timing diagram showing the time relationship of radio waves, and FIG. 3 is a block diagram showing the operating principle of a conventional radar device. In the figure, (1) is the exciter, (2) is the distribution W, (
31 is a frequency modulation section, (4m) (4bl is a synthesizer,
(5) is a power amplification section, (6) is a diplexer, (7a
) (7b) is a circulator, (8a) (8b)
is a radar antenna, and (9) is a demodulator. (2i) is the receiving antenna, (22) is the ESM receiver, (23) is the frequency measurement unit. (24) is a pulse @ measurement section, (25) is a pulse repetition measurement section, (26) is a pulse amplitude measurement section, (27)
(28) is an interfering transmitter, and (291 is a transmitting antenna. In Figure 1, the same or corresponding parts are indicated by the same reference numerals.

Claims (1)

[Claims] an exciter that generates and pulse modulates a radar carrier wave, a distributor that divides the output of the exciter into two, a frequency modulation section that frequency modulates one output of the distributor, and the remaining output of the distributor. a combiner that combines the outputs of the frequency modulation section; a power amplification section that amplifies the power of the output of the combiner; and a carrier wave that is frequency-modulated and a carrier that is not frequency-modulated using the frequency difference between the outputs of the power amplification section. a diplexer that separates the diplexer, two circulators that switch between the output of the diplexer and the received signal, a radar antenna that transmits a non-frequency modulated carrier wave as a linearly polarized wave and receives the reflected wave from the target, and Another radar antenna transmits a modulated carrier wave with a polarization plane orthogonal to the polarization plane of the radar antenna and receives the reflected wave from the target, and the reflected wave of the frequency-modulated carrier wave received by the radar antenna is transmitted as described above. a demodulator that inputs the signal via the circulator and demodulates it with a characteristic inverse to the modulation characteristic; and a synthesizer that inputs the reflected wave of the non-frequency modulated carrier wave received by the radar antenna via the circulator and combines it with the output of the demodulator. What is claimed is: 1. A radar device comprising: a combiner separate from the combiner; and a radar receiver.