JPH01193681A - Radar apparatus - Google Patents

Abstract

PURPOSE:To contract the apparatus scale of a transmitter, in each antenna system, by a method wherein the signal from a pulse compression and modulation generator is subjected to frequency conversion with respect to the signal from a transmission signal generator by a transmission system and a receiving signal is passed through a pulse compression filter in a receiving system. CONSTITUTION:The modulation signals from the first and second pulse compression and modulation generators 31, 41 are subjected to frequency conversion with respect to the signal from a transmission signal generator 10 by the fifth and sixth frequency converters 32, 42 to obtain frequency modulated expansion pulses (a), (b) which are, in turn, subjected to frequency conversion along with the signal from a local oscillator 7 by the first and second frequency converters 9, 19 and amplified by the first and second power amplifiers 8, 18 to be emitted to the air through circulators 2, 12 and antennae 1, 11. The reflected waves impinging on a target pass through the antennae 1, 11 as receiving signals and are subjected to frequency conversion on the basis of the signal from the local oscillator 7 by the second and fourth frequency converters 3, 13 to become IF signals which are, in turn, amplified by the first and second IF amplifier 4, 14 to be inputted to the first and second pulse compression filters 33, 43. At this time, any signal other than the signals subjected to pulse compression and modulation is suppressed. The signals passed through the filters 33, 43 are detected by the first and second detectors 5, 15 to become video signals which are, in turn, inputted to the first and second signal processors 6, 16 and the output thereof are displayed on a display device 21.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pulse radar device having a plurality of antennas.

[Conventional technology]

As shown in Fig. 2, in a radar device having multiple antennas, the transmitted wave from antenna (1) is reflected by a target object, and in addition to returning to antenna +11, it is also reflected by buildings etc.
It may enter the antenna αυ and be detected as a signal.

In order to avoid the above-mentioned misrecognition, conventional radar equipment deals with this by changing the transmission frequency.

A block diagram of a conventional radar device is shown in FIG.

In FIG. 4, (l) is the first antenna, (2) is the first circulator, (3) is the second frequency converter, (
4) is the first IF amplifier, (5) is the first detector, (6
) is the 10th signal processor, (7) is the first local oscillator, (
8) is the first power amplifier, (9) is the first frequency converter, aI is the first transmission signal generator, αυ is the second antenna, α is the second circulator, fil is the fourth Frequency converter, 041 is second IF amplifier, l! 9 is the second detector.

α0 is a second signal processor, and 11η is a second local oscillator.

(2) is the second power amplifier, (11 is the third frequency converter).

(1) is a second transmission signal generator, and 0υ is a display device.

Here, 111 to α1 will be referred to as a first antenna system, and aυ to ■ will be referred to as a second antenna system.

In the first antenna system, a first transmission signal generator α1
is a frequency modulated stretched pulse signal made with .

A signal from the first local oscillator (7) is received, frequency-converted by the first frequency converter (9), and then sent to the first power amplifier (
8), and is radiated into the air through the first circulator (2) and the first antenna il+.

The signal that becomes a reflected wave from the target is the first received signal.
The signal passes through the antenna (1) and the first circulator (2), and is frequency-converted by the signal from the first local oscillator (7) at the second frequency converter (3) to become an IF multiplied signal.

This IF multiplied signal is amplified by the first IF amplifier (4).

It is detected by the first detector (5) and becomes a video signal.
0 signal processor (6), and the target video is sent to the display device ■
displayed in υ. The same goes for the second antenna system, but if the target reflected wave of the transmitted signal from the first antenna +11 mixes into the second antenna al due to multiple reflections, it passes through the second circulator fi3 and is converted into a fourth frequency converter. Enter vessel 0. This fourth frequency converter αJ is connected to the tenth local oscillator (
Since the bandpass filter corresponding to the frequency 7) is provided, the mixed signals mentioned above are eliminated here.

[Problem to be solved by the invention]

Such conventional multi-antenna radar equipment has independent local oscillators with different frequencies, and has a scale similar to that of two independent radar equipment.

The object of the present invention is to overcome the above-mentioned problems of the prior art.

[Means to solve plot @]

In general, a phased array antenna radar has a relatively low average power, but the pulse width of the transmitted signal is lengthened to ensure long range performance. On the other hand, pulse pressure mk is applied to increase the distance resolution of the target. This pulse compression filter is used as a method for solving the problem.

That is, in both the first antenna system and the second antenna system, the transmission system frequency-converts the signal from the pulse compression modulation generator into the signal from the transmission signal generator. The receiving system was configured to pass the received signal through a pulse compression filter.

[For production]

With the above basic configuration, the pulse compression modulation methods of the first antenna system and the 20th antenna system are changed.

Thereby, even if a signal transmitted from the first antenna system is mixed into the second antenna system due to multiple reflections, it can be suppressed by the pulse compression filter of the reception system.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a block diagram.

0 and I2υ are exactly the same as those of the above-mentioned conventional device.

Gυ is the first pulse compression modulation generator, C33 is the fifth frequency converter, (to) is the first pulse compression filter, (4
1) is a second pulse compression modulator, (42) is a sixth frequency converter, and (43) is a second pulse compression filter.

Fig. 3 shows an example of a pulse compression modulation expansion pulse, and (a) shows a transmission signal generator α [first frequency modulation in which the modulation signal from the first pulse compression modulation generator Gυ is frequency-converted into a signal. stretch pulse. (b) is a second frequency change expansion pulse after frequency conversion of the modulation signal from the second pulse compression modulation generator (41) to the signal from the transmission signal generator αQ.

The first frequency modulated expansion pulse (a) is transmitted by the local oscillator (7)
The signal is frequency-converted by the first frequency converter and power amplified by the first power amplifier (8).

First circulator (2) and first antenna il+
is radiated into the air through the The signal that hit the target and became a reflected wave is transmitted as a received signal to the first antenna il+ and the first circulator (2) and t-, and is then sent to the second frequency converter (3) as a signal from the three local oscillators (7). The frequency is converted by , and an IF multiplied signal is obtained. This IF multiplied signal first IF
It is amplified by an amplifier (4) and then passed through a first pulse compression filter (
to). At this time, signals other than those subjected to the first pulse compression modulation are suppressed. The signal that has passed through this first pulse compression filter is:

The signal is detected by the first detector (5) and becomes a video signal, which is input to the first signal processor (6). Its output is displayed on Q
displayed in υ. The same applies to the second antenna system.

〔Effect of the invention〕

As described above, even if the frequency of the local oscillator or the frequency of the transmitting signal generator is the same in a radar device having multiple antennas, the present invention changes the modulation method and applies a pulse compression filter to the received signal. By passing through the antenna, it is possible to suppress the mixing of received signals between the antennas, and it is possible to reduce the size of the transmitter device.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a multi-antenna radar device showing an embodiment of the present invention, FIG. 2 is a conceptual diagram showing the mixing of received signals due to multiple reflections of the multi-antenna radar, and FIG. FIG. 3 is a schematic waveform diagram of a signal in which the transmitted waves are subjected to different critical wave number modulations. FIG. 4 is a block diagram of a conventional multiple antenna radar device. fi+ is the first antenna, (2) is the first circulator, (3) is the second frequency converter, (4) is the first IF
An amplifier, (5) a first detector, and (6) a first signal processor. (7) is a first local oscillator, and (8) is a first power amplifier. (9) is the first frequency converter, (II is the first transmission signal generator, 1υ is the second antenna, α2 is the second circulator, Q3 is the fourth frequency converter, Q41 is the second
Engineering F amplifier, a! 9 is the second detector, the wire is the second signal processor, αη is the second local oscillator, α樟 is the second power amplifier, a9 is the third frequency converter, and the wire is the second transmitter. signal generator, Qυ is the display device, 0υ is the first pulse compression modulation generator, C (3 is the fifth frequency converter, (to) is the first pulse compression filter, (41) is the second pulse Compression modulation generator, (42) is the sixth frequency converter, (43) is the second pulse compression filter, (a) is the first frequency modulation expansion pulse, (b) is the second It is a frequency modulated expanded pulse. Note that the same parts in Figure 9 are denoted by the same symbols.

Claims (1)

[Claims] a transmission signal generator; a first pulse compression modulation generator that generates a first pulse compression modulation signal; and a fifth frequency converter that converts the frequency of the transmission signal generator output and the first pulse compression modulation signal. , a local signal generator that generates a radar local signal, and a first frequency converter that converts the frequency of the fifth frequency converter output signal and the local signal generator output signal,
A first power amplifier that power amplifies the output of the first frequency converter, a first circulator that switches between a transmit signal and a receive signal, and a first circulator that emits the transmit signal and receives the receive signal.
a second frequency converter that receives a signal from the local signal generator and converts the frequency of the received signal; a first IF amplifier that amplifies the output of the second frequency converter; a first pulse compression filter that inputs the output and compresses the pulse; a first detector that detects the output of the first pulse compression filter and converts it into a video signal;
a first signal processor for receiving and signal-processing the video signal output from the detector; further comprising a second pulse compression modulation generator for generating a second pulse compression modulation signal; a sixth frequency converter that converts the frequency of the signal and the signal of the transmission signal generator; and a third frequency converter that converts the frequency of the output signal of the sixth frequency converter and the output signal of the local signal generator. , a second power amplifier that power-amplifies the output of the third frequency converter, a second circulator that switches between the transmitted signal and the received signal, a second antenna that radiates the transmitted signal and receives the received signal, and A fourth frequency converter receives a signal from a local signal generator and converts the frequency of the received signal, a second IF amplifier amplifies the output of this fourth frequency converter, and inputs the output and compresses the pulse. a second pulse compression filter; a second detector that detects the output of the second pulse compression filter and converts it into a video signal; and a second signal that receives the output video signal of the second detector and performs signal processing. A radar device comprising a processor and a display device that displays the output of the first signal processor and the output of the second signal processor.