JPS58195171A - Radar device - Google Patents

Abstract

PURPOSE:To expand elevation coverage and to improve the performance in suppressing clutter in the high elevation coverage by combining a main electronic scanning array and an auxiliary electronic scanning array which takes charge of the high elevation coverage. CONSTITUTION:The respective phase shifters 2A, 2B of a main electronic scanning array 1A which is swiveled integrally by a reference signal generator 7 and a beam control circuit 5 and an auxiliary electronic scanning array 1B which takes charge of high elevation coverage are controlled synchronously. The vertical coverage is combined with the elevation coverage, whereby said coverage is expanded without increasing the scanning speed. A moving target which radiates two sets of transmission outputs differing in frequency is detected with the auxiliary electronic scanning array of a relatively short range, whereby the performance in suppressing clutter is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radar device that achieves wide-elevation angle covert detection capability in an electronically scanned array radar that mechanically rotates in the horizontal direction while electronically scanning the beam in the vertical plane. It is.

Typical examples of electronically scanned array radar include phase scanned array radar, frequency scanned array radar, and phase/frequency composite array radar. The following explanation will be given by taking as an example a conventional phase scanning array radar device that performs beam scanning as shown in Fig. 2 and Fig. @S.

The first intermediate frequency transmission type signal and the first local oscillation frequency generated by the reference signal generation circuit (Gin) are frequency-mixed in the transmitter (6) to become a transmission signal, which is sent to the distribution circuit via the transmission/reception switch (8). (3), the light is divided into n parts, given a predetermined amount of phase shift in the phase shifter (2), and radiated into space from the -order radiator (1).

The above-mentioned phase shift setting amount of the phase shifter (2) is adjusted to each phase shifter (2) by the beam control circuit (i) based on the beam scanning angle command and timing from the reference signal generator main circuit (Gin). It is calculated as follows and is given via the drive circuit (4).

The transmission signal radiated in a predetermined direction in this way is partially reflected by the target, and includes a -order radiator (1), a phase shifter (2), a distribution circuit (3), and a transmission/reception switch (8). ) becomes the receiver system input.

First, it is amplified with low noise in the high frequency amplification path (9), mixed with the first local oscillation frequency from the reference signal generation circuit (7) in the first mixing circuit (to), and converted into a first intermediate frequency signal. , the second mixing circuit (b) also uses the reference signal generating circuit (7).
) and converted into a second intermediate frequency signal, which is input to the moving target detection circuit (2).

The moving target detection circuit (to) is generally referred to as MTI, and is a reference signal generation circuit (7) that detects unnecessary reflected waves from the ground surface, weather, etc. in response to the generated transmission pulse repetition frequency. It forms a filter that eliminates (clutter).

The received signal with the crafter suppressed is sent to the signal processing circuit (b).
, and is sent to the display circuit (to), where the target information is detected and displayed.

As described above, the intermediate frequency is not limited to two stages, but may be appropriately selected, such as one stage or eight stages, depending on the required frequency ζ.

As described above, an antenna beam pattern is formed in a predetermined direction.
The beam elevation angle direction is changed sequentially by time division as shown in Figure 2 to electronically scan the required elevation angle range, and Figure 8 shows the relationship between transmission timing and beam position within one elevation angle scanning period. .

! In Fig. 8, the horizontal axis is time, and in order to efficiently allocate transmission energy, each transmission pulse is: The transmission peak output is constant, and the pulse width is set as follows:
:1 Corresponding to the angle, 4;'H< is changed narrowly at low elevation angles and is changed narrowly at high elevation angles in order to satisfy the maximum detection distance.

Depending on the transmission/reception format, there is also a method in which the pulse width is constant and the transmission peak output varies according to the elevation angle, but in any case, it can be covered by the present invention and is not essential. ξHere, the explanation will proceed assuming that the transmission peak output is constant.

Within one elevation angle scanning period, (sl) to (#"n) beams are sequentially formed from low elevation angles to high elevation angles. There are various other methods such as scanning in a sequence.

However, this is also not essential to the subject of the present invention, and the explanation here will be based on the assumption that the beam is formed sequentially from low elevation angles to high elevation angles as described above.

A beam of ($1) is transmitted m times with a transmission period TI, and (1
12) beam is transmitted m times with a transmission period T2, and (#f
The beam in i) shall be transmitted with a transmission period of Ti"C"m times.Ij
From the + , ) beam to the (#n) beam, each transmission period is TIH・++−, 'r, and te, and each transmission is performed once, and 1 elevation scanning period = m (Ts+ 'h+
−+ TI)+T++ 1+ −+ Tn.

The reason why the same number of transmissions from (#l) to (#l) beams is made m times each is because the clutter reception level is high in the low elevation angle region, so the moving target detection circuit (2) eliminates m pulses.
This is to suppress clutter by forming a TI filter.

Furthermore, TI-T- takes the time required for radio waves to travel back and forth over the required detection distance as their lowest limit.

Conventional electronically scanned array radar equipment is configured as described above, and uses primary radiators (1) arranged in a linear, planar or curved shape as an electronically scanned array antenna. However, in any case, as the beam radiation direction moves away from the front direction.

However, antenna performance (gain, etc.) deteriorated, making detection over a wide elevation angle range difficult.

In the case of the planar array antenna shown in FIG. 4(&), the directivity pattern (electric field) of the -order radiator (1) is Ee(θs
)=v'''jFT, Ee(8g)=Vi by any chance, and if we focus on θ1, it approaches θl-+99'' and approaches Ee(θ1)→O.

Jin's invention was made to eliminate the above-mentioned drawbacks of the conventional technology. In addition to changing the transmission frequency of
Wide elevation angle cover detection (
(2) A secondary electronically scanned array antenna system 1ζ and a secondary electronically scanned array antenna system responsible for high elevation angle obliteration are provided compared to the main electronically scanned array antenna system responsible for low elevation angle obliteration. In this case, multiple transmit pulses are used in all beams to take advantage of the short detection distance required.
Moving target detection 1... The object of the present invention is to provide a radar device that can detect 1l11 and improve clutter and pressure performance.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

Figure 4 shows the conventional main electronic scanning array antenna as ■.
This is an example of the case where the secondary electronic scanning array antenna is ■, and ■ is responsible for low elevation angle suppression, and ■ is responsible for high elevation angle suppression. By setting (ELmln)B < (ELmax)A, the total elevation angle is This shows that overturning can be expanded from (ELmin)A to (ELmax)B.

Figure 6 shows the functional system of the present invention, excluding the beam control circuit (5), reference signal generation circuit (7), signal processing circuit α◆, and display circuit (2). One set of the same functional system corresponds to each array antenna.

FIG. 6 shows the concept of beam scanning in the elevation plane.

FIG. 7 shows this beam scanning timing.

In the present invention, 1, as shown in FIG.
) Add a sub-electronic scanning array antenna with maximum gain elevation angle B and combine both into the same rotating structure,
・ (ELmln)A ~ (ELmax)A・ (E
Lmin)B to (ELpengax)B are synchronized using different transmission frequencies to simultaneously generate a plurality of beams and perform beam scanning.

#I5 The functional system shown in FIG. 1 is basically the same as that shown in FIG. 1, both main and sub.

In the reference signal generation circuit (7) and beam control circuit (5),
Control regarding beam scanning timing is performed, an example of which is shown in FIG.

In addition, in the signal processing circuit (b) and display circuit (to),
Performs correlation processing and display of signals received by both antennas.

Furthermore, since the secondary electronic scanning array antenna system operates in a high elevation angle region, the required detection distance is usually short.

As mentioned above, since the pulse repetition period (TI) is expressed by
As shown in FIG. 7, r elevation scanning periods can be included within l elevation scanning periods in the main electronically scanned array antenna system, and each beam has eight pulses within this one elevation scanning period. can be sent, which results in "S
Moving target detection processing such as pulse erasure MTI becomes possible.

Although the above explanation has been made by taking the phase scanning array radar device as an example, it is clear that the present invention can also be applied to electronic scanning array radar in general, such as frequency scanning array radar, phase/frequency composite array radar, etc.

As described above, according to the present invention, an electronically scanned array radar is configured such that an auxiliary electronically scanned array antenna that shares high elevation angle cover is added to the (1) electronically scanned array antenna, and both antennas are By simultaneously generating beams with different transmission frequencies and scanning the respective elevation angle coverage areas in synchronization, it has become possible to achieve extremely wide elevation angle coverage. By taking advantage of the fact that there is more time in terms of beam scanning timing than in a scanning antenna system, it is possible to employ beam scanning timing that enables all-beam moving target detection processing.

[Brief explanation of drawings]

FIG. 1 is a functional diagram showing an example of the configuration of a conventional electronically scanned array radar. Figure 2 shows the superimposed plane with the configuration shown in Figure 1! A conceptual diagram showing beam scanning regarding a region. FIG. 8 is a diagram showing an example of transmission timing for performing the beam scanning shown in FIG. 2. Figure 4 shows the conventional (1) electronic gate array antenna, &
0,. o*Oh. $26 (W, □□A. A. Conceptual diagram of elevation angle subversion in the antenna. Fig. 6 is a functional diagram showing one example of the configuration of this invention. Fig. 6 is based on the configuration shown in Fig. 6. A conceptual diagram showing beam scanning related to vertical in-plane obliteration. Fig. 7 is a diagram showing an example of this beam scanning timing. IA: first primary radiator, IB: second primary radiator. ff1A: Phase shifter for @1 primary radiator, 2B: Phase shifter for second primary radiator, 5A: Beam control circuit for first primary radiator, 6B: Beam control for @2 primary radiator. Circuit, 6A: first transmitter, 6B = second transmitter. In the drawings, the same reference numerals represent the same or equivalent parts. Agent: Makoto Kuzuno) / Two-procedure amendment (spontaneous) Patent Director-General of the Agency 1, Indication of the incident, Patent Application No. 7-79478 No. 2
, Title of the invention Radar device 3, Relationship to the case of the person making the amendment Patent applicant address 2-2-3 Marunouchi, Chiyoda-ku, Tokyo Name (601) Mitsubishi Electric Corporation Representative Hitachi Katayama 4, Agent Address: 2-2-3 Marunouchi, Chiyoda-ku, Tokyo (2) Please complete the detailed statement as planned. Page Line Correction Previous Correction
Positive Rear 516 Tin Ti+1 12 6 Phase shifter Phase shifter 12 7
Phase shifter Phase shifter 12 7 5A: 1st
1st order 6: 1st order 12 8 5B: 2nd - control circuit (Delete)゛ 2 12 9 5A: 6A: 12
i 9 5B: 6B: □ □ (3) Correct figures 8, 4, 5, and 6 as shown in the attached sheet. 7. List of attached documents (1) One document stating the corrected "Scope of Claims" (2) At least one document each showing the corrected figures 8, 4, 5, and 6 1.::, :1' 1:4 Claims (1) An electronically scanned array radar that mechanically rotates in the horizontal direction while electronically scanning the beam in a vertical plane. a first electronically scanned antenna having a vertical antenna, a second electronically scanned antenna that partially overlaps or does not overlap vertically with the first electronically scanned antenna; a rotation mechanism for mechanically rotating the first and second electronic scanning antennas in a predetermined mechanical relationship in a horizontal plane around the same rotational axis;
Radar equipment that has already reached 0"""""'"5°". (2) The radar device according to claim 1, wherein the first and second electronic scanning antennas have different numbers of panels for each scanning beam.

Claims (1)

[Claims] (1) In an electronically scanned array radar that mechanically rotates in the horizontal direction while electronically scanning the beam in the vertical plane, #11 electronically scanning antenna having a predetermined vertical coverage area and this III's electronically scanning antenna The first and eighth electronic scanning antennas are fixed to each other in a predetermined mechanical relationship number ζ, and the antenna and the vertical overlapping are partially overlapped or completely (not overlapped), and the first and eighth electronic scanning antennas are fixed to each other in a predetermined mechanical relation number ζ, A rotating mechanism that performs mechanical forward rotation around the same rotation axis, and a transmitting device that supplies the transmitting frequency of the first and second electronic scanning antennas and synchronizes the beam scanning timing thereof, and has a hemispherical shape. A radar device that is capable of concealment or detection within a wide elevation angle coverage area.The radar device according to claim 1.