JPS62237373A - Phased array azimuth angle radar - Google Patents

Abstract

PURPOSE:To obtain a lightweight, inexpensive azimuth angle radar whose circuit constitution is simplified by switching the azimuth angle of a beam stepwise at intervals which are nearby a small-integer submultiple of beam width. CONSTITUTION:An azimuth angle radar which arranges the beam at an optional position by controlling the phase electrically detects a reflection echo from a target by scanning the beam through a beam scan calculating circuit 103 with a beam scan command signal from a distance gate control circuit 117. At this time, the beam which is firstly directed at intervals which are 1/m (m: integer) the beam width is changed in angle digitally in (m) stages horizontally or/and vertically. The mean value of the level of the echo in a reflection echo train received by a receiver 107 at every time the beam is switched is found and (m) mean values are stored in an averaging and storing circuit 114 together with the beam scanning direction angle. Then, their levels are compared at every beam by a level comparator 115 to decide the largest azimuth angle as a real azimuth angle.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a phased array radar that detects the azimuth of a target by detecting reflected echoes from the target. Regarding angle radar.

(Prior Art) Figure 3 shows an example of a conventionally proposed "monopulse type generator using a phased array".

1 is an antenna element, 2 is a phase shifter, 3 is a beam scanning weighing circuit, 4 is a power distribution/synthesis circuit, 5 is a T-R switch, 6 is a transmitter, 7 is a sum signal reception error detection circuit, 12 is Az
Angle error detection circuit, 13 is "El angle error detection circuit, 1
4 is an azimuth synthesis circuit, 15 is a distance gate control circuit, and 16 is a distance gate generation circuit. In this circuit, in order to know the exact azimuth of the target, the beam scanning meter circuit 3 determines the phase shift number, and the phase shift number is sent to the phase shifter 2, which determines the beam pointing azimuth. Then, a transmission pulse is applied from the transmitter 6 to the sum signal circuit of the T-R switch 5, and the power distribution circuit 4. Phase shifter 2. Antenna element 1 is sent out into space. Then, the reflected echo from the target object passes through the antenna element 1, the phase shifter 2°, the power distribution/synthesizing circuit 4, and the sum signal receiving amplifier circuit 7. A
Z difference signal reception amplification circuit 8. El difference signal receiving amplification circuit 9 amplifies each, and Az angle error detection circuit 12. E
1 is added to the angle error detection circuit 13.

Az angle error detection circuit 12. El angle error detection circuit 1
The output of No. 3 is added to the azimuth calculated by the beam scanning calculation circuit 3 by the azimuth synthesis circuit 14 and output.

(Problems to be Solved by the Invention) According to the conventional device having the configuration described above, since the power distribution/synthesizing circuit 4 is configured to output the sum, Az difference, and El difference output signals, and as shown in FIG. As is clear from the structure of
Since three channels of reception amplification circuits are required for the sum, Az difference, and El difference, there are disadvantages in that the circuit structure is quite complex, and the weight and price are also increased.

The present invention solves the drawbacks of the conventional device, and the circuit configuration is significantly simplified.

The purpose of this invention is to provide a phased array azimuth radar that is lightweight and inexpensive.

(The only way to solve the problem is to take advantage of the fact that the phased array can scan the beam easily and at high speed, and switch the beam azimuth in several stages at intervals of about a fraction of the beam width.) , every time the beam is switched, several to several tens of Hals? are transmitted, the average value of the echo size of the received echo train is taken, and these are memorized,
By digitally controlling the beams by comparing the size of each beam, even if the pointing accuracy is inferior to the conventional monopulse method, the circuit configuration is simple because there is only one receiving channel. This is greatly simplified, and the above-mentioned problems are solved.

(Example) An embodiment of the present invention shown in the drawings will be explained in detail below.

In FIG. 1 showing an embodiment of the present invention, 1o1 is an antenna element, 102 is a phase shifter, 1o3 is a beam scanning calculation circuit, 104 is a power distribution/synthesis circuit, and 1o5 is a T-R
S'f ノ+, 106 is the transmitter, 1o7 is the receiver, 1
12 is an A/D converter, 113 is a multiplexer, 114
115 is an average storage circuit, 115 is a level comparison circuit, 1,160,000 angle synthesis circuit, 111 is a distance error detection circuit, 117 is a distance gate control circuit, and 118 is a distance gate generation circuit.

Figure 2 is a graphical representation of the beam width and reception level when a pencil beam is directed in space. In Figure 2, (a) shows the beam in the direction of the target. (b) and (e) are the states in which the central force of the pencil beam (a) is oriented, respectively, ■, ■
,■,■ When pointing to the position, Az axis, E
This shows that the received signal level is proportional to each beam shape when cut along the l-axis.

As an example, a case where m = 2 and Az angle and El angle scanning will be explained. Now, the beam scanning calculation circuit 103 calculates and directs the beam to the position shown in FIG. 2, and the pulse train from the transmitter 106 is transmitted to the T-R switch 105. Power distribution and synthesis circuit 104. After phase shifter 102.

Suppose that it is transmitted from antenna element 101.

As shown in FIG. 2, since the target is within the binim (2), a reflected echo train will be received. This reflected echo train is an antenna element) 101. Phase shifter 102, power distribution and synthesis circuit 104. T-R switch 105 and receiver 10
7, the detected distance error detection circuit 111. Distance gate control circuit 117. The distance is measured by a distance gate represented by a distance gate generation circuit 118. At the same time, from the distance gate control circuit 117, the beam scanning calculation circuit 10
3, a beam scanning command signal is sent to cause the beam to scan in the order of beams ■, ■, ■, ■, ■ in FIG.

The multiplexer 113 is switched every time the beam is switched to ■, ■, ■, ■ in synchronization with the beam scanning calculation circuit 103, and the nine reflected echo trains are stored in the averaging/memory circuit 114 and averaged. Ru.

In the example in Figure 2, the target is the area where the beams ■, ■, and ■ overlap, so when the beams are directed toward ■ and ■,
, almost no reflected signals from ■ can be received. Receive with beam ■, ■.

The relationship between the magnitudes of the reflected signals stored in the averaging/memory circuit 114 is proportional to the antenna beam shape shown in FIG. 2, and as shown in (b) l (e) in FIG. The size is represented by points b and c, and in this example, the average value of one reflected echo train is a > b > c. This magnitude comparison is performed by a level comparison circuit 115,
Based on this error signal, the busy azimuth synthesis circuit 116 calculates the true direction of the target by 4Az.
On the axis (■+θB/4), on the El axis (θ−θB/
4) will be determined and output. (where θB is the beam width) However, since the field beam width of the phased array antenna depends on the scanning angle, calculations regarding these beam positions may be performed on the direction cosine plane.

(Effects of the Invention) According to the present invention having the above-described configuration, it is possible to digitally control the beam even though it takes more time due to the increased number of pulses compared to the conventional monopulse method and is inferior in terms of pointing accuracy. In other words, by controlling the inside of the beam (
By dividing, a considerable effect is expected, and since the receiving sequence is simplified to just one channel, the nine-circuit configuration becomes significantly simpler, and not only the hardware equivalent to a microcomputer is sufficient for the entire circuit. 2 It has the advantage that the weight is significantly reduced and it can be manufactured at low cost.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram showing one embodiment of the present invention, and FIG.
The figure is a diagram for explaining the operation of the embodiment, and FIG. 3 is a block circuit diagram showing the configuration of a monopulse radar using a conventional phased array.

Claims (1)

[Claims] In a phased array azimuthal radar that electronically controls the phase and places the beam at an arbitrary position, when a reflected echo from a target is detected by scanning the beam, it is 1/m of the beam width (where m is an integer). ), the azimuth of the initially directed beam is digitally switched in m steps within the beam width, horizontally, vertically, or in a combination thereof, and each time the beam is switched, a row of reflected echoes is reflected from the target. Find the average value of the magnitude of the echoes, store m of the average values together with the beam scanning azimuth in a storage circuit, then compare the magnitudes for each beam and find the largest azimuth. A phased array azimuth angle radar configured to determine the azimuth angle.