JPH03259772A - Radar equipment - Google Patents

Abstract

PURPOSE:To remove interference between beams and to narrow down a transmission pattern and a reception pattern to the same extent by transmitting plural sent pulses while varying the transmission direction continuously, and changing modulation formats among the sent pulses. CONSTITUTION:A modulator 4 imposes FM chirp modulation upon the sent pulses, which are shifted in phase through transmission/reception modules 11-1N and sent to the space. The phase shift quantities of the M sent pulses by the modules 11-1N are so controlled that the respective pulses are different in transmission direction. Further, the operation of the modulator 4 is controlled so that the format of the chirp modulation is switched between an up-chirp and a down-chirp modulation format alternately at sent pulse intervals. After the M sent pulses are sent, the respective modules 11-1N are switched to a reception mode and the pulses are outputted to a digital beam formatter 2. For received signals corresponding to the received beams, the up-chirp modulation or down- chirp modulation is selected by demodulators 51-5M corresponding to the modulation formats of the sent beams. The interference due to transmission from an adjacent beam is removed by the demodulation processing.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention applies to digital beam forming (DBF).
) technology.

[Conventional technology]

Figure 3 is a configuration diagram of a conventional radar device of this type.
This is, for example, the ``MARCH LO'' long-range three-dimensional radar.
-A LONG RANGE 3D RADARCon
ference Proceedings of Mi
Litary Microwaves). In the figure, 11 to IN are transmitting/receiving modules forming an antenna, 1 is an exciter, 2 is a digital beam former, and 13 is a target detector.

Next, the operation will be explained.

The transmitted pulse is converted into an RF signal by the exciter 1 and sent to each of the transmitting/receiving modules 11 to IN. Each transmitter/receiver module performs a predetermined phase shift on the input RF multiplied signal, amplifies it, and radiates it from an antenna. At this time,
The amount of phase shift in each transmitter/receiver module is shown in Figure 4 (a
) is controlled so that a transmission pattern like this is obtained.

After the transmission is completed, each transmitting/receiving module is switched to the receiving mode, and after amplification, the reference signal (L, O; L.

cal0scillator) and is subjected to analog/digital (A/D) conversion. Further, the digital beam former 2 forms a plurality of receiving beams as shown in FIG. 4(b). From the signals of each receiving beam, only significant signals are extracted at the target detector 3.

[Problem to be solved by the invention]

Conventional radar devices are configured as described above, so the transmission pattern needs to be wider than the reception pattern, which causes problems such as reduced antenna gain and susceptibility to clutter signals. was there.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to obtain a radar device in which the transmission pattern can be narrowed by G to the same extent as the reception pattern.

[Means for Solving the Problems] A radar device according to the present invention transmits a plurality of transmission pulses while continuously changing the transmission direction, and also changes the modulation format between the transmission pulses to prevent interference between beams. It was designed to be removed.

[Effect]

The demodulator of each receive beam in this invention is controlled to be tuned to the modulation type of the corresponding transmit pulse.

〔Example〕

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

In FIG. 1, 4 is a modulator, 1 is an exciter, 11 to IN are transmitting/receiving modules, 2 is a digital beam former, 151 to 5M are demodulators, and 3 is a target detector.

Next, the operation will be explained.

The transmitted pulse is subjected to FM chirp modulation by the modulator 4, further converted into R and F by the exciter 1, and then sent to each transmitting/receiving module 11.
After being phase shifted by ~IN, it is amplified and transmitted into space. The transmission pulse is composed of M pulses as shown in FIG. 2(a), and the amount of phase shift in each transmission/reception module 11 to IN is controlled so that each pulse is transmitted in a different direction. Furthermore, the operation of the modulator 4 is controlled so that the chirp modulation format is alternately switched between up-chirp and down-chirp between each transmission pulse.

After transmitting M transmit pulses, each transceiver module 1
1 to IN switch to the reception mode, amplify and detect the received signal, perform A/D conversion, and output the result to the digital beam former 2. digital·
The beam former 2 performs calculations such as Fourier transform to form a plurality of receiving beams corresponding to the transmitting beam. The received signal corresponding to each received beam is chirp modulated by a demodulator 51-5M. For the operation of each demodulator 51 to 5M, either up-chirp demodulation or down-chirp demodulation is selected depending on the modulation format of the corresponding transmission beam.

This demodulation process removes interference caused by transmission from adjacent beams. This situation is shown in FIG. 2(b). In other words, the beam i received signal (RF) includes the beam (i+1) transmitted echo in addition to the beam i transmitted echo, but the beam i received signal after demodulation corresponds to beam (i -1-1). It does not include any signals.

In the above embodiment, a case has been described in which the transmission modulation format is switched from FM chirp modulation to up/down, but other modulation formats, such as code arrangement using phase modulation, may be switched, and the same method as in the above embodiment may be used. It has the effect of

〔Effect of the invention〕

As described above, according to the present invention, a plurality of transmit pulses are transmitted while continuously changing the transmission direction, and the modulation format is changed between the transmit pulses, so that both the transmit beam and the receive beam can be narrowed. This has the effect of providing a radar device with high target detection ability.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a diagram showing the configuration of a radar device according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of transmitted and received signals in the radar device according to an embodiment of the present invention, and FIG. This figure shows the configuration of a conventional radar device, and FIG. 4 is an explanatory diagram of transmission and reception patterns of the conventional radar device. 11 to IN are transmitting and receiving modules, 1 is an exciter, 2 is a digital beam former, 13 is a target detector, 4 is a modulator, and 51 to 5M are demodulators. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) In a radar device for searching for a target, which includes means for continuously transmitting a plurality of transmission pulses while changing the transmission direction, and means for simultaneously forming a plurality of reception beams corresponding to each of the transmission beams. , A radar device comprising means for changing a modulation method between adjacent transmission beams, and demodulation means for demodulating in a method compatible with the modulation method, compatible with a reception beam.