JPS6027875A - Radar equipment - Google Patents

Abstract

PURPOSE:To enable simultaneous searching and tracking of targets at long and short distances by synthesizing a plurality of transmission pulses different in the frequency and pulse width in a time series and transmitting them, which are then received through a plurality of optimal BPFs. CONSTITUTION:Transmission pulses A and B with the frequencies f1 and f2 and the pulse widths z1 and z2 of transmission pulse generators 11 and 11 are added with an adder 13 to make a synthesized transmission pulse C, which is inputted into an amplifier 10 and radiated from an antenna 1 through a circulator 2. On the other hand, a radar reflection signal inputted from the antenna 1 is mixed with a received reflected wave IF by a mixer 3 through a circulator 2 to make a signal D, which is distributed with a distributor 12 and passed through BPFs 5 and 5 with the center frequencies fIF1 and fIF2 to create video outputs E and F with a detector 6. The band widths B1 and B2 of the BPEs 5 and 5 are set at 1.2/z1 and 1.2/z2 to make an optimal filter with respect to the reflected wave IF thereby enabling the detection of optimum signals without deterioration in S/N ratio.

Description

[Detailed description of the invention] The present invention relates to a pulse radar device.

First, a conventionally used radar device will be explained with reference to FIG. In Figure 1, (1) is the antenna, (2)
is a circulator, (3) is a mixer, (4) is an IP amplifier, (5) is a bandpass filter, (6) is a detector, (7) is a radar signal processor, (8) is a local signal generator, ( 9) is a reference signal generator, (1 (I is an amplifier, and (11) is a transmission pulse generator.

The transmission pulse with two frequencies fT and a pulse width of 2 generated by the reference signal generator (9) and the transmission pulse generator (11) is amplified by the amplifier H and sent to the circulator (2) and the antenna (
1) and is transmitted into the air. The transmitted wave hits the target and becomes a reflected wave, which is input to the antenna (1) and mixer (3).
It is mixed with a local signal from one local signal generator (8) and converted into an intermediate frequency (hereinafter simply referred to as IP) signal.

This IF signal is amplified by an IP amplifier (4), optimally filtered by a bandpass filter (5), detected by a detector (6), and sent to a radar signal processing device (7).

(2) In general, pulse radar devices require distance resolution and long-distance detection or tracking, so in order to improve distance resolution, it is necessary to narrow the pulse width.

In order to improve long-range detection or tracking performance, it is necessary to increase the transmit power or narrow the receiver bandwidth. On the other hand, if the bandwidth of the receiver is B, the bandwidth B is generally I/cn = 1.2/Z, and the optimum bandwidth is determined by the pulse width. Furthermore, an increase in transmission power causes many problems as it increases the limits of amplifier elements and increases the size and weight of the modulator and power supply. In order to solve such radar system design problems, conventional radar equipment has multiple transmission pulse widths, and depending on the mode, for example, the transmission pulse width is 2. The mode was set to transmit pulse z2 mode, and the mode was switched to a mode with a narrow pulse width and distance resolution for short-range targets, and a mode with a wide pulse width and narrow receiver bandwidth for long-range targets.

Such conventional radar devices cannot perform optimal signal processing for short-range targets and long-range targets at the same time.

(3) This invention improves the shortcomings of such conventional devices, and its features include changing the frequency and pulse width of a plurality of transmission pulses, synthesizing them in time series, transmitting them, and combining them with each other when receiving them. The goal is to obtain multi-channel output signals through several optimal bandpass filters, and perform optimal signal processing on short-range targets and long-range targets at the same time.

The present invention will be described in detail below with reference to FIGS. 2 and 3.

In FIG. 2, (11 to (11)) are the same as those shown in FIG. 1, (j2) is a distributor, and (15) is an adder.

Frequency f, from the first transmit pulse generator (jla).

A first transmit pulse of pulse width z1 and a frequency f2. from the second transmit pulse generator (11b). The second transmission pulse B having a pulse width z2 is added by an adder (13) to create a composite transmission pulse 0. The synthesized transmission pulse 0 is sent to an amplifier (10
)K input, and pass it through the circulator (2) to the antenna (1
). Further, the radar reflected signal input from the antenna (1) passes through the circulator (2) (4) and the received reflected wave IP becomes D by the mixer (3). This signal is distributed by a distributor (12), passes through a first bandpass filter (5) with a center frequency fIF1 and a second bandpass filter (5) with a center frequency 'IF2, respectively, and a detector (6).
) to become a first video output E and a second video output F. The bandwidth B of the first bandpass filter (5) is equal to 1.
2/z1. The bandwidth B2 of the second bandpass filter (5) is B
2-1-2/Z2, so the received reflected wave IFK
On the other hand, it is an optimal filter and can perform optimal signal detection without degrading 8/N.

Since the present invention is configured as described above, it is possible to simultaneously track or detect short-range targets and long-range targets that require resolution that was previously impossible, and the above-mentioned drawbacks of the prior art can be eliminated. .

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of a conventional radar device, Fig. 2 is a block diagram showing an embodiment of the present invention, and Fig. 3 is a block diagram showing an embodiment of a conventional radar device.
The figure is a waveform diagram of each part for explaining the operation of Fig. 2, and (1
) is the antenna, (2) is the circuit element (5) -ta, (3) is the mixer, (4) is the IP amplifier, (5) is the bandpass filter, (6) is the detector, and (7) is the radar signal processing. Device. (8) is a local signal generator, (9) is a reference signal generator, (11) is a transmitting pulse generator, (12) is an amplifier.
) is a distributor. (13) is an adder. Note that in FIG. 1, the same or corresponding parts are designated by the same reference numerals. Agent Masuo Oiwa (6)

Claims (1)

[Claims] A radar device comprising: a reference signal generator; a plurality of transmit pulse generators that generate transmit pulses with different frequencies and pulse widths based on the output of the reference signal generator; a local signal generator that generates a local signal based on the output of the signal generator; an adder that adds and synthesizes the output signals of the plurality of transmission pulse generators; and an amplifier that amplifies the output of the adder; an antenna that transmits the output of the amplifier toward the target and receives a reflected wave reflected from the target; a mixer that mixes the reflected wave received from the antenna with the local signal of the local signal generator; A radar device comprising: an intermediate frequency amplifier that amplifies the output of the mixer; a distributor that distributes the output of the intermediate frequency amplifier; and a plurality of bandpass filters and detectors connected to the distributor. (1)