JPH01223380A - Radar equipment for identifying quadrant - Google Patents

Abstract

PURPOSE:To upgrade a function of judging a range of a quadrant where a target exists, by performing a synthesization of beam patterns from projection beam patterns of more than one pseudo random code signals and a received beam pattern switched over to a high speed operation. CONSTITUTION:A transmitting/receiving antenna section 10 has two antennas T11 and T12 for transmission and two antennas R13 and 14 for reception. A transmitter/receiver section 100 transmits or receives a radio frequency (RF) radio wave modulated by several kinds of pseudo random codes while detecting a correlation between transmitted pseudo random code signals and received pseudo random code signals to compare correlation output levels and switches a correlation output. Then, a judging section 60 uses a synthetic pattern output signal produced by an output of the transmitter/receiver section 100 to form a DC voltage signal and a computation output thereof is used to judge a quadrant where a target exists and a range thereof by a binary signal.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention uses radio waves modulated with a pseudo-random code to perform correlation processing on a detected signal of a reflected wave from a target, thereby determining the range of the quadrant in which the target exists. The present invention relates to a quadrant identification radar device with improved determination accuracy.

[Prior Art and Problem to be Solved by the Invention] Conventionally, as an active target detection system, a single 1041 random code signal is used to correlate reflected signals from targets in all directions with the same transmitting and receiving antenna. However, a target detection radar device that detects only when a target approaches is known. This is to detect when the distance to the target has become less than a predetermined value, but in this case the direction of the target could not be detected.

In addition, two transmitting and receiving antennas are provided as the target direction detection device, and the transmitting antenna has a projection quadrant for two or more pseudorandom code signals, and a receiving quadrant in which the receiving antenna is switched at high speed. There is a direction identification radar device that synthesizes detection quadrant patterns and performs correlation processing to detect a weak reflected signal of a target within the detection quadrant to obtain target approach and target direction information.

This has the problem that although the target can be clearly detected toward the center of the quadrant, the quadrant determination of the target direction becomes unclear near the boundaries of adjacent quadrants.

A conventional direction-discriminating radar system is shown in FIG. Fifth
In the figure, the radio frequency (R
F) The output is passed through the distributor 16 to a pair of modulators 17, 1
8, each of which receives a pseudorandom code generator 2.
After being modulated with a pseudorandom code generated from 4 and 25, it is radiated to the outside via transmitting antennas 11 and 12. The radio waves radiated to the outside are reflected by the target object and reach the microwave switching circuit 19 via a pair of receiving antennas 13 and 14. This reception input is switched by the microwave switching circuit 19 together with the clock of the clock generator 20, and the switching output is sent to the demodulator 21 together with the output of the RF oscillator 15, homodyne-detected, and the output is divided into four by the power divider 22. be done. These distributed signals are sent to pseudorandom code generators 24,
Correlation is performed using the same code as the pseudorandom code generated from No. 25. Outputs from the correlators 26-29 are sent to a determiner 30 via low-pass filters 31-34.

The determiner 30 is composed of two comparators 301 and 302 and two switches 303 and 304, and the outputs of the correlators 26 and 27 are input to the comparator 301 via filters 31 and 32, respectively, and compared. output to the switch 303,
Further, the outputs of the correlators 28 and 29 are filtered by the filters 33 and 29, respectively.
The signals are input to the comparator 302 via 34, compared, and output to the switch 304. The output from the clock generator 20 is input to switches 303 and 304, and the output from the comparator 3
01, 302 output and switch 303
The output from the switch 304 is X, , X, and the output from the switch 304 is
,X, is obtained. This switch 304 connects the output of the comparator 302 to output terminals X, .

In addition, when the target detection signal is switched in synchronization with the reception switching of the left and right receiving antennas 13 and 14, and is connected to the left receiving antenna 13, it is output to the output terminal X3.
When connected to the receiving antenna 14, it appears at the output terminal X4. Similarly, the output of the comparator 301 is synchronized with the left and right receiving antennas 13 and 14, and appears at the output terminals X, , X, respectively. The left and right receiving antennas 13 and 14 are combined with the upper and lower receiving antennas 11 and 12 to form beams 1 to 4 in four directions as shown in FIG. 2. Therefore, if the left and right receiving antennas 13 and 14 are connected by a microwave switching circuit, and the outputs of the comparators 301 and 302 are synchronized and switched by switches 303 and 304, the output end of beam L becomes X, and beam 2 becomes X4, and beam For beam 3, a target detection signal appears at X1% beam, and at X8 for beam 4.

In this way, when trying to detect the approach of a target object and the direction in which the target object exists, with conventional devices, the target can be clearly detected toward the center of the quadrant, but the quadrant determination of the target direction is unclear near the boundary of the quadrant. It has the problem of becoming.

When detecting a target object using a radar device having a quadrant identification function, an object of the present invention is to not only detect that the target object has approached within the distance, but also to detect the range of the target's existence quadrant. The objective is to improve the range determination function of

[Means to solve the problem]

According to the present invention, an antenna section each having two transmitting and receiving antennas transmits and receives RF radio waves modulated with a plurality of types of pseudorandom codes, and also transmits and receives RF radio waves modulated with a plurality of types of pseudorandom codes, and a transmission pseudorandom code signal and a reception pseudorandom code signal. After detecting the correlation, the correlation output levels are compared, a transceiver unit switches the correlation output, a composite pattern output signal from the output of the transceiver unit is used to form a DC voltage signal, and the calculation output is used to generate a DC voltage signal. A quadrant identification radar device is provided, comprising: a determination unit that determines the quadrant and range in which a target exists based on a value signal.

(Embodiment) FIG. 1 shows a radar device having a quadrant identification function as an embodiment of the present invention.

The transmitting/receiving antenna section 10 includes a pair of transmitting antennas T (upper)
11ST (bottom) 12, and a pair of receiving antennas R (left) 13 and R (right) 14.

The oscillation wave of the RF oscillator 15 of the transmitter/receiver section 100 is transmitted to the distributor 1.
6 to a pair of modulators 17 and 18, and are modulated by signals from pseudorandom code generators 24 and 25, and the modulated waves are transmitted to the transmitting antennas T (upper) 11 and 11, respectively.
(Bottom) Emitted from 12.

On the other hand, the reception input captured by the pair of reception antennas R (left) 13 and R (right) 14 is sent to the switching circuit 19 together with the clock of the clock generator 101, where the left and right received radio waves are switched and sent to the demodulator 21. Ru. This demodulated input is demodulated by the output of the RF oscillator 15, sent to the power divider 22, divided into four parts, and each correlator 26, 27
, 28 and 29. The signal from each pseudo-random code generator 24, 25 and each correlator input are correlated, and the correlated output signal is passed through a low-pass filter 261, 2, respectively.
Comparators 301, 3 via 71, 281, 291
02 and sent to the switch section 30. The first and second switches 303 and 304 are operated by the clock of the clock generator 101 (x, , xt).
Switching is controlled between (x, , x,). The output terminals X, -X4 switch the connection of the left and right receiving antennas 13, 14, and as shown in FIG.

This transceiver section is a device similar to a conventional direction identification device. The output signals from the switches 303 and 304 are converted into DC voltage signals Bl, 82, B after amplifying and holding the signals of each beam in the amplification/holding section 40.
3 and B4 to the calculation units 8-1 to 4 of the calculation unit 50, and four inputs are input to each calculation unit.

In the apparatus of the present invention shown in FIG. 1, the received level pattern synthesized from the transmitting and receiving antennas is drawn in the shape of an arctangent as shown in FIG. In the device of the present invention, each of the calculation units 1 to 11h4 of the calculation unit 50 is a universal trigonometric function generator (for example, AD639 type manufactured by Analog Devices), and calculates a calculation output signal using the following equation.

As shown in Figure 2, when a target exists in the θ angle direction from the center of the quadrant, the reflected radio waves from the target are detected by beams 1 to 4 and output as DC voltage signals B1 to B4 at their respective reception levels. Ru.

The calculation output signals of each calculation 8-1 to F4114 are positive and negative DC voltage signals corresponding to θ angles in both left and right directions with the center of each quadrant as a reference.

The respective arithmetic unit output signal levels are determined by decision units 61 and 62.

At 63 and 64, a comparison is made to see if the positive and negative reference voltages are between +V0F and -v■v, and if they are within the positive and negative reference voltages, a digital output l is output, and if it is outside the positive and negative reference voltages, that is, V , <-V□2 or V, >+V□, a digital output of 0 is output. As mentioned above, the characteristics of the arithmetic unit Vs (■) for the ■ quadrant are shown in FIG. 3 as the detection range calculation output. In this case, accuracy decreases as it gets closer to the boundary, so the accuracy can be improved by cutting. FIG. 3 shows the arithmetic unit output corresponding to the beam output in quadrant 2 in FIG. 2, and characteristic diagrams can be similarly drawn for the x, n, and m quadrants.

Here, as seen from Figures 2 and 3, +V□,
Since 1 and 1□ are voltages corresponding to ±tan-'45°, only the output of the determiner in the quadrant where the target exists is 1, and the outputs of other determiners are 0.

For example, if the target exists in the ■ quadrant, only the output of the determiner 64 becomes 1.

Table 1 The output of the determiner for each quadrant is as shown in Table 1.

FIG. 4 shows the window characteristics of the output of the determiner, and shows the case of quadrant 2 in the figure. As is clear from the figure, the output of this detection judge shows H (-1) only between +V II[F and -V*tr, and outside +V
).

A comparator exhibiting such window characteristics is generally easily constructed using a pair of operational amplifiers.

〔Effect of the invention〕

According to the apparatus of the present invention, a beam pattern is synthesized using a projection beam pattern of two or more pseudorandom code signals and a receiving beam pattern that is switched at high speed, and after correlation processing, the weak beam pattern of a target in each beam is It is possible to accurately determine the detection range by detecting reflected signals and performing signal determination for each composite pattern using a determiner.

Furthermore, it is possible to obtain information on the approach of the target object within a certain distance and the direction of the target, ie, quadrant information on where in the four quadrants the target exists.

Furthermore, by changing the determination reference voltage value, it is possible to make the detection range in the target direction variable, and to arbitrarily widen or narrow the range in a specific direction.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a direction identification radar device as an embodiment of the present invention, FIG. 2 is a diagram showing a pattern synthesized by the transmitting and receiving antenna of FIG. 1, and FIG. 3 is a diagram of the arithmetic unit of FIG. 1. Figure 4 is a diagram showing the detection range of the output; Figure 4 is a waveform diagram of the detection/judgment output of the determiner in Figure 1; Figure 5 is a diagram showing a target object detection device for detecting the approach of a target object in the conventional method. be. lO... Transmitting/receiving antenna section, 11, 12... Transmitting antenna, 13, 14... Receiving antenna, 15... RF oscillator, 16... Distributor, 17,
18... Modulator, 19... Switching circuit, 21... Demodulator, 22... Power divider, 24
, 25... pseudorandom code generator, 26, 2
7, 28, 29... correlator, 261, 271
, 281 , 291 . . . low-pass filter, 301 , 3
02... Comparator, 30... Switch section, 40...
Amplification and hold section, 50... Arithmetic section, 60... Judgment section, 100.
... Transmitter/receiver section, 101... Clock generator. 2nd (3) Combined reception pattern diagram

Claims (1)

[Claims] 1. An antenna unit each having two transmitting and receiving antennas, which transmits and receives RF radio waves modulated with multiple types of pseudorandom codes, and transmits and receives a transmitted pseudorandom code signal and a received pseudorandom code signal. a transmitter/receiver section that compares correlation output levels after detecting correlation with the transmitter/receiver section, a switch section that switches the correlation output of the transmitter/receiver section, and a DC voltage signal formed using a composite pattern output signal from the output of the switch section. , a determination unit that determines the quadrant and range in which a target exists based on a binary signal using the calculation output. 2. The quadrant identification radar device according to claim 1, wherein the quadrant range of the target is calculated using an arctangent function and the presence or absence of the target is determined by a determiner. 3. In order to perform calculations in the target quadrant range using the arctangent function, each input of the calculation unit is set to B1, B2, B3, and B4, and the calculation unit outputs are V_S_ I , V_S_II, V_S_III, and V_S.
_IV is calculated by the following formula, V_S_ I = tan-1 [B2-B4/B1-B3]
V_S_II=tan-1 [B3-B1/B2-B4]V
_S_III=tan-1 [B4-B2/B3-B1]V
_S_IV=tan-1 [B1-B3/B4-B2] The method according to claim 1, further comprising discriminating the quadrant in which the target exists and the quadrant in which the target does not exist in the discriminator corresponding to each quadrant using binary numbers. Radar device for quadrant identification.