JP2593171B2 - Quadrant identification radar device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention correlates a detection signal of a reflected wave from a target using a radio wave modulated by a pseudo-random code to determine a range of a phenomenon in which a target exists. The present invention relates to a quadrant identification radar device having improved determination information.

[Prior art and problems to be solved by the invention]

Conventionally, as an active target detection device, a target detection radar that performs correlation processing of reflected signals from omnidirectional targets with the same transmitting and receiving antennas using a single pseudo-random code signal, and detects only when the target is approaching. Devices are known. This is to detect that the distance to the target has become less than a predetermined value, but in that case, the direction of the target could not be detected.

Further, two transmitting and receiving antennas are provided as target direction detecting devices, respectively, and two or more pseudo-random code signal projection quadrants by the transmission antenna and a reception quadrant in which the receiving antenna is switched at a high speed. There is a direction identification radar device that synthesizes a detection quadrant pattern, performs a correlation process, detects a weak reflected signal of the target in the detection quadrant, and obtains information on the approach and target direction of the target.

This has a problem that the target can be clearly detected in the center direction of the quadrant, but the determination of the quadrant in the target direction becomes unclear near the boundary in the adjacent quadrant.

A conventional direction identification radar device is shown in FIG. In FIG. 5, the radio frequency (RF) output from the RF oscillator 15
The output is sent to a pair of modulators 17 and 18 via a splitter 16,
After being modulated by the pseudo-random codes generated from the pseudo-random code generators 24 and 25 respectively, they are radiated outside via the transmitting antennas 11 and 12. The radio wave radiated outside is reflected by the target object and a pair of receiving antennas
From 13,14, it reaches the microwave switching circuit 19.
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 by the power divider 22 into four parts. Is done. The distributed signals are respectively supplied to the pseudo-random code generator 2 by correlators 26 to 29.
Correlate with the same code as the pseudo-random code generated from 4,25. Outputs from the correlators 26 to 29 are transmitted to the determiner 30 via low-pass filters 31 to 34.

The decision unit 30 includes two comparators 301 and 302 and two switches 30.
The outputs of the correlators 26 and 27 are input to a comparator 301 via filters 31 and 32, respectively, are compared and output to a switch 303, and the outputs of the correlators 28 and 29 are filters respectively. The signals are input to a comparator 302 via 33 and 34, are compared, and are output to a switch 304. Said switch output X _1, X ₂ is output from the clock generator 20 is input is input together with the comparator 301 and 302 output to the switch 303, 304 from the switch 303
From 304, outputs X ₃ and X ₄ are obtained. The switch 304 is output X _3, X ₄ and the output of the comparator 302 by the timing pulse signal produced by the clock generator 20, also switched in synchronization with the reception switching of each of the right and left receiving antenna 13 target detection signal to the output terminal X ₃ when connected to the left side of the receiving antenna 13, when connected to the receiving antenna 14 at the output end X _4. Similarly, the output of the comparator 301 is synchronized with the left and right receiving antennas 13 and 14, and output terminals X ₁ and X _{2 respectively.}
Appears in The left and right receiving antennas 13 and 14 form beams 1 to 4 in four directions as shown in FIG. 2 by a combined pattern with the upper and lower receiving antennas 11 and 12. Therefore,
Microwave switching circuit to connect the left and right receiving antenna 13, also to the output end X ₃ of switching the beam 1 is synchronized by a switch 303, 304 a comparator 301 and 302 output, beam 2 X _4, the beam 3 is X _1, beam 4 will be the target detection signal appears on the X _2.

Thus, in the conventional apparatus, when trying to detect the approach of the target object and the direction in which the target object exists, the target can be clearly detected in the center of the quadrant, but the quadrant determination of the target direction is unclear near the boundary of the quadrant. There is a problem that it becomes.

An object of the present invention is to detect a target object by a radar device having a quadrant identification function, not only to detect that the target has approached within a certain distance, but also to detect the range of the target existence quadrant. The purpose is to improve the quadrant range determination function.

[Means for solving the problem]

According to the present invention, an antenna unit having two transmission and reception antennas, respectively, transmits and receives RF radio waves modulated with a plurality of types of pseudo-random codes, and generates a transmission pseudo-random code signal and a reception pseudo-random code signal. A transceiver unit for comparing the correlation output levels after detecting the correlation, a switch unit for switching the correlation output of the transceiver unit, and a plurality of output signals from the switch unit were converted into a DC voltage signal via an amplifier unit. After that, when the output signal is off, the amplifying and holding unit, which is stored in the holding unit that does not operate when the output signal is off, and the DC voltage signal of the amplifying unit is input to each arithmetic unit, and each arithmetic unit is used in both left and right directions with reference to the center of each quadrant. And a computing unit for outputting a positive / negative DC voltage signal corresponding to the θ angle of each of the computing units, and comparing whether each computing unit output level is positive or negative and exists within the reference voltage. A quadrature identification radar device comprising: a determination unit that performs binary determination and performs a correct determination of a boundary while specifying a target existence quadrant that has recognized a target in the four quadrants; Is done.

〔Example〕

FIG. 1 shows a radar apparatus having a quadrant identification function according to an embodiment of the present invention.

The transmitting / receiving antenna unit 10 is a pair of transmitting antennas T (upper)
11, T (lower) 12, and a pair of receiving antennas R (left) 13, R
(Right) Consists of 14.

The oscillation wave of the RF oscillator 15 of the transceiver unit 100 is transmitted to the pair of modulators 17 and 18 via the distributor 16 and is modulated by the signals from the pseudo random code generators 24 and 25, and the modulated waves are transmitted respectively. Radiated from antennas T (upper) 11 and T (lower) 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, and switches the left and right reception radio waves to be sent to the demodulator 21. You. The demodulated input is demodulated by the output of the RF oscillator 15 and sent to the power divider 22, divided into four parts, and sent to the correlators 26, 27, 28 and 29. The signals from the pseudo-random code generators 24 and 25 are correlated with the correlator inputs, and the correlation output signals are compared with each other by the comparators 301 and 302 via the low-pass filters 261, 271, 281, and 291, respectively, and sent to the switch unit 30. . The first and second switches 303 and 304 are switched between (X ₁ , X ₂ ) and (X ₃ , X ₄ ) by the clock of the clock generator 101. Output X ₁ to X ₄ is a second goal of the four directions of the beams 1-4, as shown in FIG switches the connection of the left and right receiving antenna 13, the output signal of the transceiver section 100 in the detection signal. This transceiver unit is a device similar to a conventional direction identification device. switch
The output signals from 303 and 304 are amplified and held by each beam signal in the amplifying / holding unit 40, and then, as DC voltage signals B1, B2, B3 and B4, the computing units No. 4 to No. 4 of the computing unit 50.
And four inputs are input to each computing unit.

The pattern of the reception level combined from the transmitting and receiving antennas in the apparatus of the present invention shown in FIG. 1 is drawn in an arc tangent shape as shown in FIG. In the apparatus of the present invention, each of the arithmetic units No. 1 to No. 4 of the arithmetic unit 50 is a universal trigonometric function generator (for example, AD639 type manufactured by Analog Devices), and calculates the arithmetic output signal by the following equation.

As shown in FIG. 2, when the target exists in the θ-angle direction from the center of the IV quadrant, 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. You.

The arithmetic output signals of the arithmetic units No. 1 to No. 4 output positive and negative DC voltage signals corresponding to θ angles in both the left and right directions with reference to the center of each quadrant.

The output signal levels of the respective computing units are compared by a decision unit 61, 62, 63, 64 to determine whether they are between a positive / negative reference voltage + V _REF and −V _REF. 1 is output, and the voltage is outside the positive and negative reference voltages, that is, V _S <−V _REF
Or, if V _S > + V _REF , digital output 0 is output. As described above, the operation unit V _S (IV) characteristic for the IV quadrant is shown in FIG. 3 as a detection range operation output. In this case, the accuracy is reduced near the boundary, so that the accuracy is improved by cutting. FIG. 3 shows the operation unit output corresponding to the beam output in the IV quadrant of FIG. 2, and similarly, I, II, III
A characteristic diagram can also be drawn for a quadrant.

Here, as can be seen from FIGS. 2 and 3, + V _REF
And -V _REF so that the ± tan ^-1 45 ° corresponding to the voltage, only the quadrant of the decision output of the target is present is 1 next other decision output is 0.

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

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

FIG. 4 shows the window characteristic of the output of the determiner, and shows the case of the IV quadrant in the figure. As is clear from the figure, the output of the detection / determination device is H ( ₌₌ ) only between + V _REF and −V _REF.
1), and L (= 0) outside + V _REF : −V _REF . A comparator exhibiting such a window characteristic is generally easily configured using a pair of operational amplifiers.

〔The invention's effect〕

According to the apparatus of the present invention, a beam pattern is synthesized by a projection beam pattern of two or more pseudo-random code signals and a reception beam pattern switched at high speed,
After the correlation processing, a weak reflected signal of a target in each beam is detected, and a signal determination is performed for each of the combined patterns by a determiner, so that an accurate detection range can be determined. Further, it is possible to obtain direction information of the approach of the target object within a certain distance and the presence of the target, that is, quadrant information as to where in the four quadrants the target object exists.

Further, by changing the determination reference voltage value, the detection range in the target direction can be changed, and the range in a specific direction can be arbitrarily widened or narrowed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a direction identification radar device as one embodiment of the present invention, FIG. 2 is a diagram showing a pattern synthesized by a transmitting / receiving antenna of FIG. 1, and FIG. 3 is a computing unit of FIG. FIG. 4 is a diagram illustrating a detection range of an output, FIG. 4 is a detection determination output waveform diagram of the determination unit in FIG. 1, and FIG. 5 is a diagram illustrating a target object detection device for detecting approach of a target object in a conventional method. is there. 10: 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 …… Pseudo random code generator, 26,27,28,29 …… Correlator, 261,271,281,291 …… Low-pass filter, 301,302 …… Comparator, 30 …… Switch section, 40 amplifying and holding section, 50 calculating section, 60 determining section, 100 transceiver section, 101 clock generator.

Claims (1)

(57) [Claims] An antenna unit having two transmitting and receiving antennas for transmitting and receiving RF radio waves modulated by a plurality of types of pseudo-random codes, and correlating a transmitted pseudo-Rakodam code signal with a received pseudo-random code signal. A transceiver unit for comparing the correlation output level after detection, a switch unit for switching the correlation output of the transceiver unit, and after converting a plurality of output signals from the switch unit to a DC voltage signal via an amplification unit, An amplifying and holding unit that is stored in a holding unit that does not operate when the output signal is off; a DC voltage signal of the amplifying unit is input to each arithmetic unit, and each arithmetic unit has θ in both the left and right directions with respect to the center of each quadrant. Computing unit that outputs positive and negative DC voltage signals corresponding to angles, and compares whether each computing unit output level is within the positive and negative reference voltages Display 2 value each, 4 determiner unit make the right decision boundaries while specifying the target presence quadrant that recognized target in the quadrant, the quadrant discriminating radar apparatus characterized by comprising the city.