JPH0634751A - Phase matching system for receiver - Google Patents

Abstract

PURPOSE:To eliminate proper phase differences among three series of receiving parts in a monopulse receiver for a monopulse radar. CONSTITUTION:In a receiver having three series of receiving parts 1, 2, 3, in which receiving signals of three channels are subjected to frequency conversion by means of a common local signal and amplified at the same phase, output phases of the receiving parts 1, 2, 3 are detected by a phase detection part 4 on the basis of a reference signal for phase detection and a phase of a local signal to be fed to the receiving parts 2, 3 of channels except for a reference channel is adjusted in phase parts 5, 6. On the basis of an output phase of the receiving part 1 of the reference channel, data on output phases of the receiving parts 2, 3 due to the same input and phase shift quantities of phase shift parts 5, 6 are renewed and stored at regular intervals by RAMs 7, 8. In compliance with an output phase of the receiving part 1 relative to input of a test signal synchronized with the reference signal, data on a phase shift quantity is imparted from the RAMs 7, 8 to the phase shift parts 5, 6 so as to match the three series of receiving parts 1, 2, 3 to an equal phase state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a monopulse receiver used in a monopulse radar or the like, and particularly to a receiver consisting of three series of receivers for detecting azimuth and elevation angle, which is unique to each receiver. The present invention relates to a receiver phase matching method for removing a phase difference.

In a monopulse radar, four antennas having the same beam characteristics are arranged at left and right (L, R) and up and down (U, L) symmetrical positions respectively, and received signals from the respective antennas are up and down. Signal added in the direction (LO = U
L + LL, RO = UR + LR) and a signal (UO = UL + UR, LO ₀ = LL + LR) added in the left-right direction, a sum signal Σ (= LO + RO) obtained by adding all signals
And the difference signal ΔAZ subtracted in the horizontal direction and the vertical direction
(= LO-RO) and ΔEL (= UO-LO ₀ ) are created and input to each of the three series of reception systems, and the sum signal in the reception output signals is used as a reference to calculate the difference between the two types of difference signals. By obtaining the phase difference, the azimuth angle and elevation angle of the target object are detected.

In such a monopulse receiver,
It is necessary to sufficiently remove the inherent phase difference between the receiving systems in advance, but the phase matching method in this case can be performed automatically and easily, and can be performed for each PRF (pulse repetition period). Therefore, it is required to be able to cope with phase fluctuations due to temperature changes, lapse of time, and the like.

[0004]

2. Description of the Related Art In a monopulse receiver, a phase difference between two kinds of difference signals in the output signals of three series of receivers is used as a reference to determine the azimuth angle and elevation angle of a target object. To detect. Therefore, if there is an inherent phase difference between the three series of reception systems, the phase difference between the received signals will be detected as different values, and it will not be possible to obtain accurate azimuth and elevation angles. , It is necessary to perform phase matching between the receiving units.

Conventionally, as a phase matching method in a monopulse receiver, a test signal is input from an SG (signal generator) and a local oscillator (local oscillator) signal is input to a frequency downmixing mixer in each of the three series receiving sections. The phase can be manually controlled, and the output phase of the reception unit of each series is measured by, for example, observing a waveform by a synchroscope to perform phase matching.

[0006]

However, since the phase matching method of the conventional monopulse receiver relies on the waveform observation, not only the accuracy of the phase matching is poor, but also the matching state is caused by the temperature fluctuation and the secular change. There was a problem that there was a deviation.

The present invention is intended to solve the problems of the prior art as described above, and in a monopulse receiver or the like, phase matching between the three series of receiving sections can be automatically performed, and By using the period other than the radar signal reception period to perform phase matching with the test signal at all times, it is possible to cope with phase fluctuations due to temperature fluctuations and aging changes. It is intended to provide a scheme.

[0008]

SUMMARY OF THE INVENTION In the present invention, three series of receiving units 1, 2, and 3 for frequency-converting received signals of three channels by a common local signal and amplifying them in phase are provided. In the receiver having the receivers 1, 2 ,, of each channel with reference to the phase detection reference signal.
The phase detector 4 for detecting the output phase of the reference signal 3, the phase shifters 5, 6 for adjusting the phases of the local signals supplied to the receivers 2, 3 for channels other than the reference channel, and the receiver 1 for the reference channel. RAMs 7 and 8 for periodically updating and storing the data of the output phases of the receiving units 2 and 3 and the phase shift amounts of the phase shift units 5 and 6 of channels other than the reference channel with the same input as the output phase. RAMs 7 and 8 according to the output phase of the reference channel for the test signal synchronized with the phase detection reference signal in the test signal input period.
From the phase shifters 5 and 6 to the phase shifters 5 and 6, the three series receivers 1, 2 and 3 are matched to the same phase state.

[0009]

According to the present invention, the receiver is a receiving section 1 for frequency-converting the received signals of three channels by a common local signal and amplifying them in phase.
It has a few.

In such a receiver, the phase detector 4
Is provided to detect the output phases of the receiving units 1, 2 and 3 of each channel with reference to the phase detection reference signal,
When the receiving unit of the reference channel is the receiving unit 1, the phase shifting units 5 and 6 are provided in the receiving units 2 and 3 of the other channels, and the phase of the local signal supplied to the receiving units 2 and 3 is increased. To be able to adjust.

Further, RAMs 7 and 8 are provided to shift the output phases of the receivers 1 and 2 of the channels other than the reference channel at the same input with reference to the output phase of the receiver 1 of the reference channel (phase difference from the reference signal). The data of the phase shift amounts of the phase units 5 and 6 are stored while being updated periodically.

When phase matching is performed in the operating state of the receiver, a test signal synchronized with the phase detection reference signal is supplied to the three-series receivers 1, 2 and 3 during the radar signal non-reception period, for example, every PRF. Given during the test signal input period. At this time, the RAM corresponding to the output phase of the receiver 1 of the reference channel detected by the phase detection unit 4
The phase shift amount data stored in 7 and 8 are given to the phase shift units 5 and 6, respectively.

As a result, the receiving units 2 and 3 adjust the phase of the local signal so that the output phase thereof becomes equal to the output phase of the receiving unit 1 of the reference channel. A few can be matched to equal phase states.

[0014]

FIG. 2 shows an embodiment of the present invention, showing a block configuration at the time of phase matching of a monopulse receiver including receivers of respective channels Σ, AZ and EL. In the numbers, the subscripts 1, 2 and 3 are Σ and A, respectively.
The receivers of the Z and EL channels are shown.

11_1,11_2,11₃ Is set at the input of each receiver.
The stripped coupler (DC), 12 is the coupler 11_1,11_2,1
1₃ Is a switch (SW) for supplying a test signal to.
Thirteen _1,Thirteen_2,Thirteen₃ Are receivers, and_1,
14_2,14₃ Is a mixer, 15 _1,15_2,15₃ Is the intermediate frequency
The number amplification (IF) unit. 16_1,16_2,16₃ Is each Miki
Service 14_1,14_2,14₃ Phase shift of the local signal supplied to
Bowl, 17_1,17₂ Are the phase shifters 16_2,16₃ Oke
This is a RAM that stores data of the amount of phase shift.

Reference numeral 18 is a common phase detection circuit, 19 is a limiter (LIM), 20 is a phase detection unit (PHD), 2
1 analog-digital converter (A / D), 22 denotes a selector (SEL) for selecting the reception output of each receiver ₁₃ 1, 13 _2, 13 _3. Reference numeral 23 is a control circuit commonly provided for each receiving system.

Each of the receiving units 13 _1, 13 _{2 and} 13 ₃ receives the received signals of the Σ channel, the AZ channel and the EL channel in the mixers 141 _1, 142 _and 14 _{3 respectively} and the phase shifter 16 _1,
Frequency conversion is performed by a local signal that is commonly given via 16 _2, 16 ₃ to generate an intermediate frequency (IF) signal, and IF units 151 _, 15 _2, 15 ₃ amplify this IF signal and receive it. Output signals RX (Σ), RX (AZ), RX
(EL) is generated.

The RAMs 17 _{1 and} 17 ₂ receive the reception output signals RX (A
Z), RX (EL) phases (phase difference from the phase detection reference signal) and the amount of phase shift in the phase shifters 16 _{2 and} 16 ₃ are expressed as the output phase of the receiving section of the reference channel with respect to the same input. Is stored as a reference. Reception output signal RX at the time of setting the phase shift amount data in the RAMs 17 _{1 and} 17 ₂ .
The phase difference between the reference signals for phase detection in (AZ) and RX (EL) can be measured by using the phase detection circuit 18 and switching the selector 22.

The data stored in the RAMs 17 _{1 and} 17 ₂ are updated by initial setting when the power is turned on, for example. Alternatively, it is periodically updated according to the control from the control circuit 23 every time a certain time passes. Which method is used is determined according to the environmental conditions of use of the device.

FIG. 3 shows the phase difference and the detection in the phase detection circuit.
It shows the relationship with the output signal level and shows the common phase.
Reception output signal and phase detection reference in the detection circuit 18
Phase detection signal level V with respect to the phase difference Δθ with the signal_PD
And shows the characteristics. ROM17_1,17₂ In Figure 3
Remember the relationship between the indicated phase difference and the phase detection signal level.
Of the AZ and EL channels
Phase shifter 16 of each receiver _2,16₃ The amount of phase shift of this data
Set by.

FIG. 4 is a time chart showing the operation of each part when updating the RAM data. SW12 is the control circuit 23
It is turned on for each PRF based on the control of A, and a test signal is supplied, whereby the A / D output of the AZ channel and the A / D output of the EL channel are switched according to the switching of the selector 22.
/ D output occurs.

RAM (R / W) CONT of the control circuit 23
The signal becomes write (W) for each PRF, and the value of the phase shift amount control signal PSCONT for the phase shifter at this time is
The A / D output is written into the RAMs 17 _{1 and} 17 ₂ as an address, but at this time, the RAM (AZ / AZ from the control circuit 23 is written.
EL) CONT signal specifies RAM 17 ₁ AZRA
And M, according to become ELRAM specify the RAM 17 _2, are written into the RAM 17 ₁ and RAM 17 _2.

In the operating state, SW12 is the control circuit 2
Under the control of _{No. 3 , the} signal is turned on during the period other than the period for receiving the radar signal, and the test signal is supplied to the DC 11 _1, 11 _2, 11 ₃ , so that the receiving unit 13 _1, 13 _2, 13 ₃ The test signal is commonly received. The test signal is always synchronized with the phase detection reference signal by, for example, being created based on the same reference oscillator signal.

The common phase detection circuit 18 receives the reception output signal RX (Σ) of the reception unit 13 ₁ , limits the amplitude in the LIM 19, detects the phase difference from the phase detection reference signal in the PHD 20, and A In / D21, this is converted into a digital signal and output.

On the other hand, the RAM (R /
W) The CONT signal becomes read (R), and A / D21
Since the contents are read out from the RAMs 17 _{1 and} 17 _{2 using} the output as an address, the value of the corresponding phase shift amount control signal PSCONT is read out using the output of the A / D 21 as an address. _The amount of phase shift at _1, 16 ₂ is set.

FIG. 5 is a basic time chart for phase matching. As shown in FIG. 5, the phase calibration of the receiving parts of the AZ channel and the EL channel is performed by a test period (TES) provided for each cycle (TP) of the radar PRF.
T. This is performed by inputting a test signal to T), but a control signal RAM (AZ / EL) from the control circuit 23.
The data in the RAMs 17 _{1 and} 17 ₂ are alternately read by the CONT, so that the data is alternately performed in the reception units 13 _{1 and} 13 ₂ of the AZ channel and the EL channel.

The case of phase matching of the AZ channel will be described below. Radar PRF TEST. At T, a test signal, which is a high-frequency signal for phase matching, is given to each receiving unit. At this time, the reception output signal RX (Σ) of the Σ-channel reception unit 13 ₁ is L in the common phase detection circuit 18.
The amplitude is limited to a constant amplitude by the IM 19, and the phase is detected by the PHD 20. At this time, it is assumed that the level of the detection signal was V _PD1 at the time of the previous measurement, but became V _PD2 this time.

The detected value V _PD2 is converted into a digital value in the A / D 21 and simultaneously input into the RAMs 17 _{1 and} 17 ₂ , but the RAM (AZ / E from the control circuit 23 is used.
By L) CONT signal, RAM 17 since only _one is addressed, the detection level V from RAM 17 _1
The data corresponding to _OD2 is output. Since the phase shifter 16 ₂ is controlled by the output of the RAM 17 _1, the phase of the reception output signal RX (AZ) of the AZ channel reception unit 13 _{2 is} the same as the reception output signal RX of the Σ channel reception unit 13 _1.
It becomes equal to the phase of (Σ), which means that phase matching has been achieved.

It should be noted that, for the EL channel receiver,
Since it has the same phase matching circuit as the AZ channel receiver, the phase matching for the EL channel receiver can be performed in exactly the same manner.

[0030]

As described above, according to the present invention, in a monopulse receiver or the like, it is possible to automatically perform phase matching between the three series receiving sections. Since this phase matching can be always performed by the test signal using the period other than the reception period of the radar signal, it is possible to cope with the phase variation due to the temperature variation or the secular change. At the same time, the data for phase matching is periodically updated and corrected, so that the phase matching between the three series of receivers can be performed accurately.

[Brief description of drawings]

FIG. 1 is a diagram showing a principle configuration of the present invention.

FIG. 2 is a diagram showing an embodiment of the present invention.

FIG. 3 is a diagram showing a relationship between a phase difference and a detection signal in a common phase detection circuit.

FIG. 4 is a time chart showing the operation of each unit when updating RAM data.

FIG. 5 is a diagram showing a basic time chart at the time of phase matching.

[Explanation of symbols]

1 receiver 2 receiver 3 receiver 4 phase detector 5 phase shifter 6 phase shifter 7 RAM8 RAM

Claims (1)

[Claims] 1. A phase detection in a receiver having three series of reception units (1, 2, 3) for frequency-converting three-channel reception signals by a common local signal and amplifying them in phase. It is supplied to a phase detection unit (4) for detecting the output phase of the reception unit (1, 2, 3) of each channel with the reference signal for use as a reference, and the reception units (2, 3) of channels other than the reference channel. Output of the phase shifter (5, 6) for adjusting the phase of the local signal and the receivers (2, 3) of channels other than the reference channel at the same input with reference to the output phase of the reference channel receiver (1) A RAM (7, 8) for periodically updating and storing the data of the phase and the phase shift amount of the phase shift section (5, 6) is provided, and is synchronized with the phase detection reference signal in the test signal input period. The test signal input By providing the phase shift amount data from the RAM (7, 8) to the phase shift unit (5, 6) in accordance with the output phase of the reception unit (1) of the reference channel, 1, 2, 3) are matched to the same phase state.