JPH01181246A - Antenna fault detecting method - Google Patents

Abstract

PURPOSE:To accurately detect an antenna fault by removing an undesired signal from a reflection signal including the undesired signal and detecting the fault of the antenna and its power supplying system or the abnormality of adjustment state from the amplitude of a detecting signal by obtained required reflection signal. CONSTITUTION:A signal distributer 9 extracts a part of a signal (undesired signal) of a transmitter 7. Then a phase shifter 10 and an attenuator 11 are adjusted to obtain signal vector 26 so that the input signal B of a signal synthesizer 12 is just equal to the amplitude of the reception signal component included in the input signal A and the phase is opposite. Since the detector 5 can obtain a detection output voltage composed of a required reflection signal where the effect of undesired reception signal is removed, the decision of the fault of the antenna is implemented accurately.

Description

Detailed Description of the Invention (Industrial Applicability) This invention is applicable to antennas for transmitting radio waves and failures or abnormalities in the adjustment state of power supply systems such as antennas for transmitting radio waves and lines that feed them (hereinafter referred to as antennas). It relates to a method for accurately detecting failures (referred to as failures).

[Conventional technology]

A conventional method for detecting an antenna failure is to measure the size of the reflected wave of a transmitted signal at the output end of a transmitter and make a determination based on the size.

In this method, under normal conditions with no antenna failure, impedance matching between the antenna and the feed system is established at the output end of the transmitter so that the reflected signal seen from the transmitter side is sufficiently small. Here, if an antenna failure occurs, the impedance matching described above will be disrupted, resulting in an increase in reflected signals. Therefore, a failure determination circuit detects the change in the signal level, and when the reflected signal exceeds a certain value, it can be determined that an antenna failure has occurred.

Figure 7 is a system diagram of such an antenna failure detection device.
1 is an antenna that attempts to detect a failure, 2 is a power supply system that also attempts to detect a failure, and 3 is a transmitter. Reference numeral 4 denotes a directional coupler inserted between the output end of the transmitter 3 and the feed system 2, which selectively outputs reflected signals from the directions of the antenna 1 and the feed system 2. Reference numeral 5 denotes a detector, which provides a detection output proportional to the output of the directional coupler 4. Reference numeral 6 denotes a failure determination device, which determines whether the detector is normal or a failure has occurred based on the magnitude of the output of the wave detector 5.

Figures 8(a) and (b) are a signal vector diagram and a detected signal diagram, and vector 21 is the reflected signal before the antenna failure at time T in Figure 8(b) (hereinafter either vector or reflected signal will be used). (The same applies to other vectors.)
, vector 22 is a reflected signal at the time of antenna failure, and 27 is the detected output voltage at that time. 28 is the failure detection voltage,
Since the detected output voltage 27 becomes equal to or higher than the failure detection voltage 28 after the failure occurrence time T, the failure determination device 6 determines that an antenna failure has occurred.

(Problem to be Solved by the Invention) However, in this method, as shown in FIG. 7, there is another transmitter 7, and its transmitting antenna 8 is
, antenna 1 operates as a receiving antenna for the signal from transmitting antenna 8,
Vector 23 of FIG. 8 is received. Therefore, the received signal 23 is superimposed on a reflected signal caused by an antenna failure, etc., and is input to the detector 5 via the directional coupler 4.

24 is a composite vector of the reflected signal 21 and the received signal 23 before the antenna failure, and 25 is the reflected signal 22 at the time of the antenna failure.
and the received signal 23. Further, 30 is the detected output voltage at this time, and 29 is the detected output voltage when only the received signal 23 is input to the detector 5. Therefore, if the received signal is large, the detection output will be large even if there is no antenna failure and the reflected signal is small, and if it exceeds the failure detection voltage 28, it will be erroneously determined that an antenna failure has occurred. In other words, in this case, the transmitter 7 becomes a source of unnecessary signals for detecting a failure of the antenna 1, and the output of the directional coupler 4 contains unnecessary signals.

In particular, both signal frequencies of the transmitters 3 and 7 are close to each other,
If the antennas 1 and 8 are installed close together and the output power of the transmitter 7 is large, the unnecessary received signal generated by the transmitter 7 will be large and difficult to separate.
The problem was that the influence was significant.

This invention was made in order to solve the problems of the conventional method of detecting an antenna failure from the detection output voltage of a reflected signal, and it is an object of the present invention to provide an antenna failure detection method that can always accurately detect an antenna failure. purpose.

(Means for Solving the Problems) The first invention of the antenna failure detection method according to the present invention is to detect a reflected signal containing an unnecessary signal emitted from an unnecessary signal source and a part of the unnecessary signal from the unnecessary signal source. By extracting the signal and adjusting its amplitude and phase, the unnecessary signal is removed by combining it with the reflected signal containing the unnecessary signal.The antenna and its feeding system are This is designed to detect failures or abnormalities in the adjustment state.

Further, the second invention also eliminates the influence of the unnecessary signal by extracting a part of the unnecessary signal from the unnecessary signal source and subtracting the detected signal from the detected signal of the reflected signal including the unnecessary signal emitted from the unnecessary signal source. This system is designed to detect a failure in the antenna and its feeding system or an abnormality in the adjustment state from the magnitude of the signal obtained by reducing the noise.

(Operation) The first invention according to the present invention detects the unnecessary signal after removing it from the reflected signal containing the unnecessary signal emitted from the unnecessary signal source, and detects the malfunction or adjustment condition of the antenna and the feeding system based on the size of the unnecessary signal. Detect abnormalities.

Similarly, the second invention detects a reflected signal containing an unnecessary signal emitted from an unnecessary signal source, extracts and detects a part of the unnecessary signal from the unnecessary signal source, and converts the detected signal to the detected signal. The reflected signal is subtracted from the detected signal to detect a failure in the antenna and feed system or an abnormality in the adjustment state based on its magnitude.

(Examples) Hereinafter, three types of examples of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing Embodiment 1 of the present invention.
is the same as in FIG. 7, 9 is a signal splitter for extracting a part of the signal from the transmitter 7, 10 is a phase shifter for adjusting the phase of the signal, and 11 is for adjusting the amplitude. attenuator,
12 is the input signal A from the directional coupler 4 and the attenuator 1;
This is a signal combiner for obtaining a vector sum of two input signals, input signal B from 1.

Next, the operation of the first embodiment shown in FIG. 1 will be explained with reference to the signal vector diagram in FIG. 2(a) and the detected signal diagram in FIG. 2(b).

In FIG. 1, the input signal A of the signal combiner 12 is a composite signal of a signal received by the antenna 1, a reflected signal caused by an antenna failure, etc., and a signal from the antenna 8, as explained in FIG. In FIG. 2(a), vector 21
is the reflected signal before the antenna failure at time T in FIG. 2(b), and it is assumed that this becomes large as vector 22 when the antenna failure occurs. The change in the detected output voltage at this time is as shown in 27 in FIG. 2(b).

However, since there is a transmitter 7 and a transmitting antenna 8, if the signal vector received by the antenna 1 from this signal source (unnecessary signal source) is 23 in FIG. 2(a), this signal and the above-mentioned reflected signal The composite signal vector of is input to the detector 5. That is, in FIG. 2(a), vector 24 is input before the antenna failure, and vector 25 is input after the failure. Therefore, the detected output voltage at that time becomes 30 in FIG. 2(b), making it impossible to accurately determine the antenna failure. In FIG. 2(b), it is assumed that when the input voltage of the failure determiner 6 becomes equal to or higher than the failure detection voltage 28, it is determined that an antenna failure has occurred. Further, 29 indicates the detected output voltage when only the received signal vector 23 is input to the detector.

Here, a part of the signal (unnecessary signal) from the transmitter 7 is extracted by the signal splitter 9, and the input signal B of the signal synthesizer 12 is exactly equal to the amplitude of the received signal component included in the human signal A.
A signal vector 26 is obtained by adjusting the phase shifter 1o and attenuator 11 so that the phases are opposite to each other. The signal combiner 12 is A
, B, the received signal vector 23 in the input signal A and the signal vector 26 in the input signal B cancel each other out, resulting in the vector 21 or 22 of the reflected signal caused by an antenna failure, etc. only is output. Therefore, in the detector 5, the detection output voltage due to the necessary reflected signal with the influence of the unnecessary received signal removed, that is, the second
Since the value 27 shown in FIG. 3(b) is obtained, antenna failure can be accurately determined.

FIG. 3 is a configuration diagram showing Embodiment 2 of this invention.
1 is the same as in FIG. 1, and 31 is a detector for detecting the output of the signal distributor 9, 32 is a level adjuster for changing the level of the detected output signal, and 33 is a detector for the detector 5. Level adjuster 32 from human input signal A' which is the output
This is a signal subtracter for subtracting the input signal B' which is the output of the .

Next, the operation of the second embodiment shown in FIG. 3 will be explained with reference to the detection signal diagram shown in FIG. 4.

In FIG. 3, the input signal A' of the signal subtracter 33 becomes the detected output voltage 30 shown in FIG. 4, as explained in FIGS. 1 and 7. - On the other hand, the input signal B' of the signal subtracter 33 is adjusted so that it becomes the detected output voltage 29 as in FIGS. 2 and 8.

Therefore, in the signal subtracter 33, the detection output voltage 29 is subtracted from the detection output voltage 30 in FIG. 4 to obtain the signal 41, so that failure can be detected accurately.

Next, a third embodiment of the present invention is shown in FIGS. 5 and 6.

Figure 5 is a schematic system diagram of an SSB type Doppler VOR (Very High Frequency Omnidirectional Radio Beacon) for providing orientation information to aircraft. A case in which the present invention is used in a similar manner as in FIG.

In FIG. 5, as shown in FIGS. 1 and 3, 4 is a directional coupler, 5 is a detector, 6 is a failure determiner,
9 is a signal distributor, 31 is a detector, 32 is a level adjuster,
33 is a signal subtracter.

Further, 51 is a radius of 6 around the carrier antenna 55.
．． 50 sideband antenna rows arranged at equal intervals on a circumference of 5 m, 52 are 15 sideband antenna rows sequentially arranged in the sideband antenna row 51.
This is a distributor for switching power supply at time intervals of 1/00th of a second.

53 is a sideband transmitter whose frequency is adjusted to f0+9960Hz, where fo is the carrier frequency of the carrier wave transmitter 54. Note that the carrier signal is amplitude modulated at 3 OHZ.

At the output end of the sideband transmitter 53, a sideband antenna array 51
Impedance matching is performed when the power supply system including the power supply line and the distributor 52 is in a normal state. Therefore, the reflected signal at this time is small. However, as mentioned above, in the Doppler VOR, the carrier antenna is installed at a short distance of 6.5 m at the center of the sideband antenna array, and the transmission power is output approximately 10 times that of the sideband signal. . For this reason, the sideband antenna array 51 operates as a receiving antenna for the carrier signal, and the reflected signal due to the original antenna failure etc. and this received signal are superimposed and detected, so a normal failure determination cannot be made.

In FIG. 6, a signal 61 is a detected output signal based on a reflected signal from the feed system including the sideband antenna array 51 and the distributor 51, and indicates a case where a failure occurs in the sideband antenna No. 15 or its feed system. . Note that 62 is a failure detection voltage.

However, since the Doppler VOR has a carrier signal whose amplitude is modulated by 30H2, if the received detection signal of the sideband antenna based on this signal is 63, the actual output signal of the detector 5 is 64, which is accurate. It becomes impossible to make accurate failure judgments.

Therefore, in the circuit of Fig. 5 using the same method as that of Fig. 3,
A signal subtractor 33 is provided to extract the -0 part of the carrier signal from the input signal A', that is, the output signal 64, and send it to the detector 3.
When the signal detected by 1 and whose level is adjusted by the level modulator 32 is made equal to 63 and subtracted, a signal close to the wabo signal 61 is obtained, allowing accurate failure determination.

In addition, in the sideband antenna failure detection circuit of such a Doppler VOR, the time difference t is determined by comparing the failure occurrence position determined by the signal 61 and the position of the switching timing clock of the No. 1 antenna of the distributor 52 as shown in the signal 65. It is possible to accurately determine the number of a faulty antenna or its power supply system from the repetition period t0 of switching power supply and the formula 50 x t + to + 1. Therefore, it has the feature that countermeasures can be easily taken in the event of a failure.

Embodiment 3 has described the antenna failure detection of the SSB type Doppler VOR containing one sideband transmitter. However, the Doppler VOR also operates on the same principle as the SSB type. DSB with sideband transmitter
Method Doppler vOR and ASB method Doppler VO
In both methods, antenna failure can be detected using the same method as in the SSB method.

〔Effect of the invention〕

As explained in detail above, the first aspect of the present invention is to extract a reflected signal containing an unnecessary signal emitted from an unnecessary signal source and a part of the unnecessary signal from the unnecessary signal source, and to determine its amplitude and phase. The unnecessary signal is removed by combining the adjusted signal with the reflected signal that includes the unnecessary signal, and the magnitude of the detected signal from the obtained desired reflected signal is used to detect a failure in the antenna and its feeding system or an abnormality in the adjustment state. As a result, the influence of unnecessary signals other than reflected signals is removed or reduced, which compensates for the inaccuracy of failure judgment caused by the influence of unnecessary signals from unnecessary signal sources, and makes it possible to detect antenna failures. It has the advantage of accurate detection.

Furthermore, in the second invention, in addition to the above-mentioned effects, since the detected output is used, it has the advantage that it is easier to handle than high frequency waves.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a circuit showing Embodiment 1 of the present invention,
2(a) and 2(b) are signal vector diagrams and detection signal diagrams for explaining the operation of the first embodiment of FIG. 1, and FIG. 3 is a block diagram of a circuit showing the second embodiment of the present invention. Figure 4 shows
Detection signal diagram for explaining the operation of Embodiment 2 in FIG. 3, 5th
The figure is a block diagram of a circuit showing a third embodiment of the present invention.
The figure is a detection signal diagram for explaining the operation of Embodiment 3 in Figure 5, Figure 7 is a block diagram showing an example of a conventional antenna failure detection device, and Figures 8 (a') and (b) are conventional FIG. 2 is a signal vector diagram and a detected signal diagram for explaining the operation of the device. In the figure, 1 is a transmitting antenna, 2 is a power supply system such as a power supply line, and 3
is a transmitter, 4 is a directional coupler, 5 is a wave detector, 6 is a failure judge, 7 is a transmitter, 8 is a transmitting antenna, 9 is a signal splitter, 1o is a phase amplifier, 11 is an attenuator, 12 is a signal synthesizer, 3
1 is a detector, 32 is a level adjuster, 33 is a signal subtracter,
51 is a sideband antenna array, 52 is a distributor,
53 is a sideband transmitter, 54 is a carrier wave transmitter, and 55 is a carrier wave antenna. Designated Agent Kyoji Yonemoto, Director, Electronic Navigation Research Institute, Ministry of Transport Figure 3 Figure 4 1 hour T (failure occurred) Figure 7 Figure 8 1 hour T (failure occurred)

Claims (2)

[Claims] (1) In a method for detecting a failure or abnormality in the adjustment state of an antenna and its power supply system based on the magnitude of a reflected signal, the reflected signal containing an unnecessary signal emitted from an unnecessary signal source and the unnecessary signal from the unnecessary signal source are detected. The unnecessary signal is removed by extracting a part of the signal and adjusting its amplitude and phase with the reflected signal containing the unnecessary signal, and the antenna and An antenna failure detection method characterized by detecting a failure in the power feeding system or an abnormality in the adjustment state. (2) In a method of detecting a failure or abnormality in the adjustment state of an antenna and its feeding system based on the magnitude of a reflected signal, the detection signal of a reflected signal containing an unnecessary signal emitted from an unnecessary signal source is used to detect the unnecessary signal emitted from the unnecessary signal source. It is characterized by detecting a failure or an abnormality in the adjustment state of the antenna and its feeding system from the magnitude of the signal obtained by reducing the influence of the unnecessary signal by extracting a part of the signal and subtracting the detected signal. Antenna failure detection method.