JPH022107B2 - - 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, and in particular applies the principles of a transponder to monitor the attenuation of the antenna system of the radar transmitter and the receiver sensitivity. It relates to a device that monitors and displays the same.

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. An echobox 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 rotation of the radar antenna is observed using a check meter. It has drawbacks such as being difficult to observe.

In order to eliminate the drawbacks of the prior art described above, the present invention generates a specific pattern on the CRT display of a radar indicator and makes it possible to distinguish it from a real echo, so that when the overall radar performance deteriorates, To provide a radar performance monitoring device configured to make it possible to clearly indicate the amount of the decrease in steps, for example, down to -15 dB in 5 dB steps, and to quickly determine whether the performance decrease is in the transmitting system or the receiving system.

FIG. 1 is a block diagram showing one embodiment of the present invention. 1 is a monitor antenna placed near the radar antenna as shown in FIG. 9, 2 is a first directional coupler, 3 is a first detector, 4 is a first comparator, 5 is a peak hold circuit, and 6 is a 2nd comparator, 7 is a control circuit, 8 is a trigger generation circuit, 9 is a modulation signal generation circuit, 10 is a microwave oscillator, 11 is a first variable attenuator, 12 is a second directional coupler, 13 is a second 14 is a microwave modulation section, and 15 is a second variable attenuator.

As shown in FIG. 9, this device is placed near the radar antenna, receives a part of the radar transmission pulse (approximately -50 dB) by the monitor antenna 1 through spatial coupling, passes through the first directional coupler 2, The signal is sent to the first detector 3. The detected signal is sent to a peak hold circuit 5 and held at the maximum detected signal level during one revolution of the radar antenna. The signal is also sent to the first comparator 4, and the trigger generation circuit 8 operates only when the signal exceeds a certain threshold level.
The modulation signal generation circuit 9 generates a frequency modulation signal v(t) that changes intermittently as shown in FIG. 2, and an amplitude modulation signal i(t) that changes in stages as shown in FIG.
occurs. The signal v(t) changes the electronic tuning voltage of the microwave oscillator 10 such that when v _p voltage,
The frequency oscillated by the microwave oscillator 10 is equal to the radar transmission frequency f _p , and when the voltage is v _d , the voltage is adjusted so that it becomes the frequency f _d in the non-tuned region. By such a method, a test pattern without amplitude modulation as shown in FIG. 4 is generated on a CRT display of a radar indicator (not shown).

Next, the signal i(t) is a signal synchronized with the signal v(t) and applies the current of this signal to the pin diode in the microwave modulation section 14. This signal is
This is a current waveform adjusted so that FM modulated microwaves can be AM modulated up to -15dB in -5dB steps, for example, and the amount of attenuation of the microwaves is changed by controlling the current of the pin diode. . FIG. 5 is a diagram that expresses the output waveform of the microwave modulator 14 in an easy-to-understand manner.

The radio waves oscillated by the microwave oscillator 10 are the first
It is attenuated by the variable attenuator 11, a part of which is taken out by the directional coupler 12, and supplied to the second detector 13, where the detected signal level and the detected signal level held by the peak hold circuit 5 are combined. are compared by the second comparator 6, and the current of the pin diode in the first variable attenuator 11 is controlled by the signal of the control circuit 7 so that they match. With this feedback loop, power corresponding to the power radiated from the radar antenna is radiated from the monitor antenna 1 in an analog manner, and is applied to the performance inspection of the radar transmission system.

Next, the FM/AM modulated microwave output from the microwave modulation section 14 is initialized by the second variable attenuator 15. this is,
The current of the pin diode in the second variable attenuator 15 is controlled so that the sixth monitor signal 6thMS shown in FIG. 5 becomes the minimum signal S _nio of the receiver in the radar device.

By the above method, the test pattern shown in FIG. 6 is generated on the CRT display of the radar indicator. For example, if only the transmission system of a radar device is attenuated by -5 dB, the trigger generation section during one revolution of the radar antenna is narrower than that of the trigger generation circuit 8 in the radar performance monitoring device, and the first variable attenuator 11 causes -5 dB attenuation.
Since FM and AM modulated microwaves attenuated by 5 dB are radiated from monitor antenna 1, the section of the test pattern generated on the CRT display of the radar indicator becomes narrower, and the 6th pattern (arc) The result is a test pattern in which the arc angle Θ ₁ is smaller than Θ ₀ in FIG. 6 as shown in FIG.
Conversely, if only the receiving system drops by -5 dB, the test pattern section remains unchanged and only the sixth pattern (arc) disappears, as shown in FIG. 8.

As explained above, by generating a special test pattern in the radar indicator, it is very easy to see, and since there is no mechanical synchronization, it is easy to handle and stable. In the past, it was only possible to inspect radar performance degradation that exceeded -10 dB, but with the present invention, it is possible to reliably inspect for declines of up to -15 dB in -5 dB steps, significantly increasing navigation safety. It will be done. Furthermore, the effect of being able to determine whether the cause of the decline in radar performance is the transmitting system or the receiving system simply by observing the test pattern on the CRT display of the radar indicator is remarkable in practical use.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention;
Fig. 2 is a waveform diagram showing the frequency modulation signal output from the modulation signal generation circuit, Fig. 3 is a waveform diagram showing the amplitude modulation signal output from the modulation signal generation circuit, and Fig. 4 is a waveform diagram showing the amplitude modulation signal output from the modulation signal generation circuit. If there is no radar indicator
Figure 5 shows the test pattern generated on the CRT display. Figure 5 is a waveform diagram showing the frequency and power of the modulated radio waves emitted from the monitor antenna. Figure 6 is the waveform diagram generated on the CRT display after initial setup. Figures 7 and 8 are diagrams showing the test patterns on the CRT display when radar performance degradation is only in the transmitting and receiving systems, respectively, and Figure 9 is the diagram showing the radar antenna and radar test patterns. FIG. 3 is a diagram showing a position in relation to a performance monitoring device. DESCRIPTION OF SYMBOLS 1... Monitor antenna, 2... First directional coupler, 3... First detector, 4... First comparator, 5...
...Peak hold circuit, 6...Second comparator, 7...
...Control circuit, 8...Trigger generation circuit, 9
... Modulation signal generation circuit, 10 ... Microwave oscillator, 11 ... First variable attenuator, 12 ... Second directional coupler, 13 ... Second detector, 14 ... Microwave modulation section, 15 ...Second variable attenuator.

[Claims]

1. A means for receiving and detecting a part of the transmitted microwave radiated from a radar antenna of a radar device in one direction of the rotating radar antenna, a microwave generating means, and a detected signal by the detecting means during one rotation of the radar antenna. means for holding a maximum level of the voltage and comparing the level with a plurality of predetermined comparison voltage levels; and based on the output signal of the comparison means, output corresponding to the power of the transmitted microwave radiated from the radar antenna. Transmission power control means for obtaining transmission power from the microwave generation means, comparing a detected signal level by the detection means with a minimum comparison voltage level of the level comparison means, and generating a trigger signal when the detected signal level is high. a frequency modulation signal that performs a frequency sweep a predetermined number of times to match the frequency of the microwave output from the microwave generation means with the radar transmission frequency based on the trigger signal, and the microwave in synchronization with the signal. means for generating an amplitude modulation signal for amplitude modulating the output in steps; and means for amplitude modulating the microwave output of the microwave generation means controlled by the transmission power control means using the amplitude modulation signal. Radar performance monitoring, characterized in that the radar performance test pattern is generated on a CRT display of a radar indicator of the radar device, thereby making it possible to determine whether a decrease in radar performance occurs in the transmitting system or the receiving system. Device.

Claims (1)

A radar performance monitoring device characterized by being able to determine whether a receiving system is in use.