JPS5970983A - Radar performance monitor - Google Patents

Abstract

PURPOSE:To improve judging accuracy while simplifying circuitry by arranging a performance monitoring body to judge the lowering of the radar performance only in the transmission system while the video signal processing section handles the judgement in the receiving system. CONSTITUTION:In a performance monitoring body, a part of transmitted pulses are received with a monitor antenna 1 and sent to a detector 4. The detection signals are compared by 4-level comparator and a modulated signal V(t) and a monitor triggering signal MT are generated with a modulated signal generation circuit 9 by trigger signal TR. A microwave modulated in the frequency with the signal V(t) is emitted from the monitor antenna 1 via first and second variable attenuator 11 and 12. Then, in the video signal processing section, the monitor trigger signal MT generated in the performance monitoring body is passed through a binary counter/decoder 101 and an NAND circuit 102 to obtain a signal NS. An output signal given after comparison with the signal level of the microwave emitted from the monitor antenna 1 of the monitoring body and the signal NS are sent to a switching circuit 107.

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, and in particular applies the principles of a transponder to attenuate the antenna system of the radar transmitter and monitor the performance of the radar. By monitoring the sensitivity and remembering it in advance, if this echo cannot be observed on the CRT, it can be checked that the radar device is not operating normally.Meanwhile, when sailing to the open ocean With radar equipment installed on ships and the like, it is very difficult to check whether it is working properly because there is a possibility that the target itself is not there. Also, recently, overseas marine radars have been
The current situation is such that it is mandatory to be equipped with a function that can inspect for performance deterioration.

Against this background, methods that have been used to monitor the performance of radar equipment include echo boxes and check meters that use glow lamps in the detection section. The echo box is a device that receives the transmission power of the radar, charges and discharges it to the cavity resonator, and displays the echo on the radar indicator'1 (! RT display).
It is difficult to monitor the performance of only the transmission system, and it is difficult to observe the maximum deflection scale for each revolution of the radar antenna using a check meter. Recently, there have been radar performance monitoring devices that utilize the transponder principle. This is a shared S-band and X-band, is automatically tuned using an AFc loop, and has a drop of -10 dB or less for radar P P I l! Although this device is designed to erase special test patterns, it is unsatisfactory as it has a complex system configuration and malfunctions due to radar interference.

The present invention solves the drawbacks of the prior art, and is an IM! The present invention provides a high-performance viewing device that improves the visual accuracy by performing the processing in a separate section, simplifies the circuit configuration, and reduces costs.

FIG. 1 is a block diagram showing one embodiment of the present invention.

This device is comprised of a performance monitor body placed near a radar antenna (not shown) and a video signal processing section located within the radar indicator.

The main body includes a monitor antenna (1), a control circuit (2) with directionality (7), a trigger generation circuit (8), a modulation signal generation circuit (9), a microwave oscillator (with electronic tuning) (10), a second variable attenuator (11), It is composed of twelve third variable attenuators.

The video signal processing section 7 includes a binary counter/decoder circuit 101, an ON A N D circuit 102, and a 1031 binary counter/decoder circuit.
The operation will be explained using the block diagram shown in the figure.

The signal is received by the monitor antenna 1 and used with a -20 dB directionality 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. The first comparator 6 is ±1 d
a window comparator with a comparison voltage level width of B;
It consists of a 4-level comparator. 4I; The bell comparator is set at a comparison voltage level that is, for example, compared to a -15 dB mino J in 5 dB steps. The detected signals are compared with each other by a comparator, and when the detected signal level is higher than that of the output signal, the trigger signal TR shown in FIG. 2 is generated, the modulation signal generation circuit 9 is operated, and
A monitor having the same pulse waveform synchronized with the modulation signal v(t) and V(1) shown in the figure) l) Generates a signal MT. The output signal of the 4-level comparator is converted into a current by the control circuit 7, and the current of the bin diode of the second variable attenuator 11 is controlled to discontinuously control the microwave output generated from the microwave oscillator 10. Thus, the monitor antenna 1 emits an output that is a variation of the output radiated from the radar antenna.

The signal v (t) then changes the electronic tuning voltage of the microwave oscillator 10 such that v. When the voltage is applied, the microwave oscillation frequency is the radar transmission frequency f. (frequency tuned to the reception band of the radar receiver), and 1 V (when using an electric power source, the frequency of the out-of-tuning region of the radar receiver, 〆11, and the wave number f:j''h:fx) The voltage is adjusted according to the frequency modulation method.The test pattern shown in Fig. 3 is generated on the radar PPI by this frequency modulation method.Therefore, the frequency modulated microwave is transmitted to the second variable attenuator. 11, is sent to the third variable attenuator 12, and is radiated from the monitor antenna 1.
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, use a window comparator with upper and lower comparison voltage limits that correspond to this accuracy. However, when it is within this range, the LED lights up. Therefore, the maximum detected signal level during one revolution of the radar antenna is detected after the first variable attenuator 3, and then the video signal processing unit installed in the radar indicator (not shown) monitors the signal generated by the performance monitoring main unit. When the trigger signal MT (FIG. 2) is passed through the pinary counter/decoder 101 and the NAND circuit 102, the signal NS shown in FIG. 4 is obtained.

Furthermore, the microwaves radiated from the monitor antenna 1 on the main body are received by the radar antenna, and the IF receiver in the radar device sends the video signal output by the device to the video signal DC regeneration circuit 103, which converts the video signal into a standard. stabilize the level.

Then, it is sent to the second comparator 104. In the video signal that has passed through the video signal DC reproducing circuit 103 shown in FIG. 5, the microwave radiated from the monitor antenna 1 of the main body is generated as a monitor signal. The current in the pin diode of the attenuator 12 is controlled and calibrated to a constant signal level. The sixth grain monitor signal 6thMT is held by the second comparator 104 and during the hold rotation time. The held output signal and the signal NS of FIG. 4 are sent to the gate circuit 106 to generate the gate signal GS to the switching circuit 107. The switching circuit 107 opens and closes the video signal according to the gate signal GS.

By the above method, the post-calibration test pattern 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 attenuated by 15 dB, the trigger generation time during one rotation of the radar antenna will be shorter than the trigger generation circuit 8 of the performance monitoring main body, and
The second variable attenuator 11 has an output attenuated by 15 dB compared to the calibrated state, and the frequency-modulated microwave is radiated from the monitor antenna 1, so the second comparator 104 of the video signal processing section has an output attenuated by 5 dB. The resulting output signal is sent to the gate circuit 106, and a gate signal as shown in FIG. 7 is sent to the switching circuit 107. Therefore, as shown in FIG. 8, stones occur on the test bar. On the other hand, the receiving system of the radar equipment is -
5a B If you want to mini, display the test pattern in which only the 6th grain pattern is dark without changing the section of the test pattern, θ0, on the CRT display of the radar indicator, as shown in Figure 9. arise.

As explained above, by allowing the performance monitoring unit and the video signal processing unit to determine performance degradation in the transmission system and reception system of the radar equipment separately, accuracy is improved and environmental conditions are Since the system failure of the bad performance monitoring main unit can be reduced to ff11, the number of parts affected by the environment can be reduced to 1,000, and stable operation can be achieved. Further, by providing the video signal processing section, there are advantages such as the ability to clearly judge the test pattern on the radar PPI.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a waveform diagram showing a monitor trigger signal, and Fig. 3 shows a test pattern that occurs in the radar PPI input when no oscillation modulation is applied. Figures 4 and 4 are diagrams showing waveform patterns, Figure 7 is a waveform diagram showing monitor trigger signals, gate signals, and switching circuit output signals, and Figures 8 and 9 are transmission system diagrams showing the radar performance. FIG. 12 is a diagram showing a test pattern for displaying water on the CRT display of the radar indicator when there is only a receiving system. 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 104... Second comparator 105 - Hold circuit 1
06...Gate circuit 107...Switching circuit Patent applicant Japan Radio Co., Ltd.Figure 4Figure 5Figure 7Figure 8Figure 9

Claims (1)

[Claims] means for receiving and detecting a portion of the transmitted microwave radiated from the radar antenna; means for comparing the detected signal with a predetermined threshold level; and means for comparing the detected signal with a predetermined threshold level; Basically, a microwave generator emits a microwave output corresponding to the threshold level, and a video signal outputted by the IF receiver on the CRT display of the radar indicator by modulating the microwave output. and a video signal processing unit that performs signal processing in accordance with a monitor trigger signal generated from the performance monitoring main unit, and detects the occurrence of radar performance degradation in the transmission system and the reception system by the performance monitoring main unit and the video signal, respectively. A radar performance monitoring device characterized in that the processing is carried out in a processing section.