JPH022109B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for use with a radar transmitter to monitor the performance of the radar. Relating to a device for monitoring and displaying sensitivity.

It is easy to inspect whether a radar device installed on the ground or a radar device installed on a ship dedicated to coastal waters is operating normally. That is, if a small fixed target is found on the CRT and remembered beforehand, and this echo cannot be observed on the CRT, it can be verified that the radar device is not operating normally.

On the other hand, with radar equipment installed on ships sailing on the open ocean, there is a high possibility that there is no target, so it is extremely difficult to inspect whether it is operating normally. Also, recently, overseas countries are requiring marine radars to be equipped with a function that allows them to test for -10 dB performance degradation.

Against this background, the methods traditionally used to monitor the performance of radar equipment include:
There are methods such as an echo box and a method of monitoring with a check meter using a glow lamp in the detection section. The echo box is a device that receives the radar's transmitted power, charges and discharges it into a cavity resonator, and displays the echo on the CRT display of the radar indicator, and requires mechanical tuning driven by a motor. Therefore, it is unsatisfactory as it has drawbacks such as being expensive and not easy to tune. Next, devices using glow lamps are very easy to tune and are inexpensive, but they can only monitor the performance of the transmission system, and the maximum deflection scale for each revolution of the radar antenna must be observed using a check meter. Therefore, it has drawbacks such as being difficult to observe.
Also, recently there is a radar performance monitoring device that utilizes the principle of a transponder. This is a device that can be used for both the S band and the X band, automatically tunes using an AFC loop, and erases a special test pattern on the radar PPI for a drop of -10 dB or less, but the system configuration is complicated and It is unsatisfactory as it malfunctions due to radar interference.

The present invention solves the drawbacks of the prior art, and is designed to determine whether the radar performance of only the transmitting system has deteriorated in the performance monitoring main unit placed near the radar antenna, and on the other hand, determine whether the radar performance has deteriorated only with respect to the receiving system. By processing the judgment in the video signal processing unit on the radar indicator side,
The present invention provides a radar performance monitoring device that improves judgment accuracy, simplifies circuit configuration, and reduces costs.

FIG. 1 is a block diagram showing one embodiment of the present invention. As shown in FIG. 10, this device is comprised of a performance monitor body placed near the radar antenna and a video signal processing section located within the radar indicator.

The main body includes 1 monitor antenna, 2 directional coupler (about 20 dB), 3 first variable attenuator, 4 detector, 5 peak hold circuit, 6 first comparator,
7 control circuit, 8 trigger generation circuit, 9
It consists of a modulation signal generation circuit, 10 microwave oscillators (with electronic tuning), 11 second variable attenuators, and 12 third variable attenuators.

The video signal processing section includes a binary counter/decoder circuit 101, a NAND circuit 102, and a 10
It is composed of a video signal DC reproducing circuit 3, a second comparator 104, a hold circuit 105, a gate circuit 106, and a switching circuit 107.
The operation will be explained below using the block diagram of FIG.

In the performance monitoring main unit placed near the radar antenna, a part of the transmission pulse (approximately -50 dB) radiated from the radar antenna is received by monitor antenna 1 through spatial coupling, and then sent to -20 dB directional coupler 2.
The signal passes through the first variable attenuator 3 and is sent to the detector 4. The first variable attenuator 3 is used together with a window comparator 61, which is one of the components of the first comparator 6, for calibration. The detection signal of the detector 4 is sent to the peak hold circuit 5, where it is held at the maximum detection signal level during the radar transmission repetition time, and becomes an input signal to the first comparator 6. 1st
The comparator 6 includes a window comparator 61 with a comparison voltage level width of ±1 dB and a 4-level comparator 62.
Consisting of The four-level comparator is set, for example, at a comparison voltage level corresponding to -15 dB of power in 5 dB steps. The peak-held detection signals are compared by a four-level comparator, and the output signals are sent to a control circuit 7 and a trigger generation circuit 8.
The trigger generation circuit 8 generates the trigger signal TR shown in FIG. 2 when the detected signal level is higher than the minimum comparison voltage level of the 4-level comparator (for example, a voltage corresponding to -15 dB), and causes the modulation signal generation circuit 9 to When operated, the frequency modulation signal v(t) shown in FIG. 2 and a monitor trigger signal MT having the same pulse waveform in synchronization with this v(t) are generated. The output signal of the four-level comparator is converted into a current by the control circuit 7, and the current of the pin diode of the second variable attenuator 11 is controlled to discontinuously control the microwave output generated from the microwave oscillator 10. The output corresponding to the output radiated from the radar antenna is radiated from the monitor antenna 1.

Next, the signal v(t) changes the electronic tuning voltage of the microwave oscillator 10, and when the voltage is v _p , the microwave oscillation frequency is equal to the radar transmission frequency f _p (frequency tuned to the reception band of the radar receiver). equal to v _d
When it is a voltage, it is the frequency of the out-of-tuned region of the radar receiver.
The voltage is adjusted so that f _d . This frequency modulation method generates the test pattern shown in FIG. 3 on the radar PPI. Therefore, the frequency-modulated microwave is sent to the third variable attenuator 12 via the second variable attenuator 11 and radiated from the monitor antenna 1. Further, the third variable attenuator 12 is used for initial calibration of the video amplitude level entering the second comparator 104 of the video signal processing section, which will be described later.

Incidentally, the initial calibration of the received detection signal level is performed as follows. In order to display that the detected signal level matches the received power with an accuracy of ±1 dB to the maximum fixed comparison voltage level of the 4-level comparator, a window comparator with upper and lower comparison voltage limits corresponding to this accuracy is used. And when it is within this range, the LED lights up.
Therefore, the current of the pin diode of the first variable attenuator 3 is controlled to control the current of the pin diode of the first variable attenuator 3 to calibrate the maximum detection signal level during one rotation of the radar antenna so that the LED lights up.

Next, in the video signal processing unit provided in the radar indicator (not shown), the monitor trigger signal MT (Fig. 2) generated in the performance monitoring main unit is passed through the binary counter/decoder 101 and the NAND circuit 102. The signal Vs shown in FIG. 4 is obtained. or,
The microwave radiated from the monitor antenna 1 on the main body is received by the radar antenna, and the video signal output by the IF receiver in the radar device is sent to the video signal DC regeneration circuit 103 to stabilize the reference level of the video signal. let And the second comparator 104
sent to. Microwaves radiated from the monitor antenna 1 of the main body are generated as a monitor signal in the video signal that has passed through the video signal DC reproducing circuit 103 shown in FIG. This monitor signal level is calibrated to a constant signal level by controlling the current of the pin diode of the third variable attenuator 12 in the main body. The sixth monitor signal 6thMT is generated by the second comparator 104 and the hold circuit 105 at a preset comparison voltage (for example, - in 5 dB steps).
(up to 15 dB) and its output signal is held for the duration of the radar transmission repetition. The held output signal and the signal Vs in FIG. 4 are sent to the gate circuit 106 and switched to the switching circuit 107.
Generates gate signal GS to The switching circuit 107 opens and closes the video signal according to the gate signal GS.

By the above method, the test pattern after calibration shown in FIG. 6 is generated on the CRT display of the radar indicator. For example, if the transmission system of a radar device is -
If it is attenuated by 5 dB, the trigger generation time during one revolution of the radar antenna will be shortened by the trigger generation circuit 8 in the performance monitoring main body, and the second variable attenuator 11 will attenuate by -5 dB from the calibrated state. Since the monitor antenna 1 emits frequency-modulated microwaves, the second
The comparator 104 sends an output signal attenuated by 5 dB to a gate circuit 106, and sends a gate signal as shown in FIG. 7 to a switching circuit 107. Therefore, as shown in FIG. 8, the section Θ ₁ of the test pattern becomes narrower, and the sixth pattern produces a dark test pattern without noise on the radar PPI.
Conversely, if the receiving system of the radar equipment drops by -5 dB, the test pattern section Θ ₀ remains unchanged, and
The test pattern in which only the 6th pattern is dark is shown on the CRT of the radar indicator as shown in Figure 9.
Occurs on the display.

As explained above, by making it possible for the performance monitoring unit and the video signal processing unit to determine the performance degradation of the transmission system and reception system of the radar equipment separately, accuracy is improved and the environment The system structure of the performance monitoring main unit, which has poor conditions, can be simplified.
The number of parts affected by the environment can be reduced,
Stable operation can be obtained. By providing a video signal processing section, there are advantages such as the ability to clearly judge the test pattern on the radar PPI.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention;
Figure 2 is a waveform diagram showing the monitor trigger signal, Figure 3 is a diagram showing the test pattern generated on the radar PPI when amplitude modulation is not applied, and Figure 4 is a NAND
A waveform diagram showing the output signal of the circuit, Figure 5 is a waveform diagram showing the output signal of the DC regeneration circuit, and Figure 6 is a waveform diagram showing the output signal of the DC regeneration circuit.
Figure 7 shows the test pattern after calibration displayed on the PPI. Figure 7 is a waveform diagram showing the monitor trigger signal, gate signal, and output signal of the switching circuit.
Figures 8 and 9 are diagrams showing the test patterns displayed on the CRT display of the radar indicator when radar performance deterioration occurs only in the transmission system and reception system, respectively, and Figure 10 shows the test patterns displayed on the radar antenna and radar FIG. 3 is a diagram showing a position in relation to a performance monitoring device. 1...Monitor antenna, 2...Directional coupler,
3...First variable attenuator, 4...Detector, 5...Peak hold circuit, 6...First comparator, 7...Control circuit, 8...Trigger generation circuit, 9...
Modulation signal generation circuit, 10... microwave oscillator,
11... Second variable attenuator, 12... Third variable attenuator, 101... Binary counter/decoder, 1
03...Video signal DC regeneration circuit, 104...Second comparator, 105...Hold circuit, 106...
Gate circuit, 107... switching circuit.

[Claims]

1. In a common digitizer correlation processing device that quantizes primary and secondary radar videos, identifies their planar distribution shapes, and detects radar targets,
A storage circuit that stores information including a history before the predetermined time at the same distance and an azimuth one point older than the input information at the predetermined time for each of the primary and secondary radar videos; A storage circuit that stores information including history before the predetermined point in time when the distance in the direction is one point older, and the primary radar information stored in the storage circuit and the quantized information of the primary radar at the predetermined point in time When the termination of the primary radar target at the point in time is detected, and there is no primary or secondary radar target being processed in the storage circuit, and there is no secondary radar target being processed in the storage circuit, the above 1. A correlation calculation circuit of the primary radar that stores information on the final target of the next radar in the storage circuit, the secondary radar information stored in the storage circuit, and the quantized information of the secondary radar at the predetermined time point The end of the secondary radar target at a given point in time

Claims (1)

and the video signal processing section having means for opening and closing the video signal according to the gate signal, the performance monitoring main body section and the video signal processing section respectively detect the occurrence of radar performance degradation in the transmission system and the reception system. A radar performance monitoring device characterized by: