JPH0360213B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A mobile body equipped with a detector for measuring the environment or equipment of the present invention and transmitting a command signal for remotely controlling the mobile body moving along a predetermined route, or The present invention relates to a reception level monitoring device for a mobile remote monitoring device, which comprises a fixed station having means for receiving signals sent from a mobile object remote monitoring device.

Conventionally, vehicles that patrol plant buildings are equipped with detectors to check the operating status of plant equipment, such as television cameras, thermometers, vibration meters, etc., and these are remotely controlled to provide the necessary measurement information. A mobile inspection device has been developed to collect

Signal transmission means between the traveling vehicle side, that is, the mobile body, and the operation panel side, that is, the fixed station, are broadly classified into wired and wireless means. In the case of wireless transmission, as the distance between the mobile and the fixed station changes, the reception level also changes. When an operation command signal is sent from a fixed station to a mobile unit, if the reception level on the mobile unit side drops, the correct command may not reach the mobile unit and the mobile unit may malfunction, and the mobile unit must be moved within the radio range. I need to maintain my body. this,
As a means for solving this problem, there is one described in Japanese Patent Publication No. 38-18755. However, the vehicle described in the above-mentioned publication has the problem of poor running performance since it is necessary to stop the vehicle every time it travels a certain distance.

The purpose of the present invention is to
An object of the present invention is to provide a mobile object remote monitoring device that can reliably maintain a mobile object within the range of radio waves.

In order to achieve the above object, the mobile object remote monitoring device of the type mentioned at the beginning according to the present invention provides a synchronization signal from a composite video signal of a television camera among the detectors transmitted from the mobile object to a fixed station. The gist is to output an alarm signal when the reception level of the synchronization signal falls below a predetermined level. That is, the mobile remote monitoring device according to the present invention extracts the horizontal synchronization signal or the vertical synchronization signal included in the composite video signal as a standard signal for monitoring the reception level, and monitors the lowest level according to the reception sensitivity. It's getting old.

Composite video signals have the strictest signal-to-noise ratio of all the signals transmitted and received between mobile units and fixed stations. Therefore, when the distance between the mobile object and the fixed station changes,
Changes in the communication state appear in the composite video signal before the control signal system to the mobile object changes. Therefore, before the control signal system to the moving body becomes abnormal, it is possible to detect the change using the composite video signal. Therefore,
By constantly monitoring the composite video signal, the moving object can be reliably maintained within the radio wave range without stopping the moving object.

Using examples below with reference to the attached figures,
The present invention will be described in more detail, but these are merely examples, and it goes without saying that various improvements and modifications may be made without going beyond the scope of the present invention.

FIG. 1 shows the configuration of a device for mounting a television camera on a mobile body and transmitting a video signal to a fixed station.

Video signal 10 output from TV camera 1
0 is sent to a modulator 2 and converted into, for example, an amplitude modulated high frequency signal 101. The transceiver 3 amplifies the input high frequency signal 101 and radiates it from the antenna 4. In this embodiment, the radiated high frequency signal 101 is received by the leaky coaxial cable 5. The leaky coaxial cable 5 is laid along the travel path of the moving object. The received signal is input to a demodulator 6, and after being restored to the original video signal, it is reproduced on a monitor 7. When a command signal is sent from a fixed station, it reaches the mobile unit through a process reverse to the above. Now, as the distance between the antenna 4 and the leaky coaxial cable 5 becomes longer, the radio field strength becomes weaker, the image quality of the monitor 7 deteriorates, and the level of the command signal sent from the fixed station decreases. The drive unit of the moving object may malfunction or become uncontrollable.

In order to avoid this problem, it is sufficient to maintain a distance between the antenna and the leaky coaxial cable so that the signal level received by the mobile unit and the fixed station always exceeds the allowable reception sensitivity.

The signals to be monitored must be (1) ones whose signal level changes only when the distance mentioned above changes, and (2) signals that can be received at all times when the main unit is in motion, that is, control signals to the moving object. It must satisfy two points: it must always be secured.

A horizontal or vertical synchronizing signal included in a composite video signal sent from a television camera is selected as a signal that meets this condition.

FIG. 2 shows a horizontal synchronization signal extracted from the composite video signal.

A waveform 22 between the horizontal synchronizing signals 20 and 21 is a video signal and corresponds to one scanning line of the screen. The level of the video signal 22 changes depending on the surrounding brightness, but the horizontal synchronization signals 20 and 21 do not change due to disturbances. However, in FIG. 1, as the distance between the antenna 4 and the leaky coaxial cable 5 increases, the levels of the horizontal synchronizing signals 20 and 21 decrease. This also applies to the vertical synchronization signal.

FIG. 3 shows the circuit block of the signal level monitoring device.

In this block, as an example, a case will be explained in which the horizontal synchronizing signal shown in FIG. 2 is selected as the standard signal.

A composite video signal sent from a television camera is reproduced on a monitor 7. A composite video signal 300 is taken out from this monitor 7 and sent to a synchronization separation circuit 31. Various synchronization separation methods have been devised in the past and have already been implemented, so a description thereof will be omitted here.

The horizontal synchronization signal 301 (usually maximum 0.3V) separated by the synchronization separation circuit 31 is sent to the booster amplifier 32, and then the connected A/D
In order to match the input level of converter 33, the maximum
It is amplified to a magnitude of 10V. This amplified signal 302
The A/D converter 33 converts the data into an n-bit digital quantity. The digital signal 303 is sent to the comparator 34, and when it becomes smaller than the level set in advance by the digital switch 35, an alarm signal 304 is output to the abnormality processing section 36. The abnormality processing unit 36 can issue a warning through a display and can also temporarily stop the movement of the mobile object.

In this embodiment, the received signal is converted into a digital quantity, but it is also possible to process the received signal as an analog quantity.

As explained above, by constantly monitoring the composite video signal, it is possible to detect changes in the communication status before the control signal system to the moving object changes. A mobile object can be maintained within the range of radio waves that can operate reliably.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the equipment configuration for transmitting a video signal to a fixed station with a TV camera mounted on a mobile body. Figure 2 is a waveform diagram of the horizontal synchronization signal extracted from the composite video signal. FIG. 3 is a block diagram of a signal level monitoring device according to the present invention. 1...TV camera, 2...Modulator, 3...
Transmitter/receiver, 4...Antenna, 5...Leaky coaxial cable, 6...Demodulator, 7...Monitor, 31...Synchronization separation circuit, 32...Booster amplifier, 33...
...A/D converter, 34...Comparator, 35...Digital switch, 36...Abnormality processing section.

Claims (1)

[Scope of Claims] 1. A moving body equipped with a television camera, and a fixed device having a means for transmitting a command signal for remotely controlling the mobile body and receiving a composite video signal transmitted from the mobile body. station, and the fixed station includes a maintenance unit that maintains the mobile unit within a range of radio waves; the maintenance unit includes separation means that separates a synchronization signal from the composite video signal; , a mobile object remote comprising: determination means for determining whether the reception level of the synchronization signal is below a predetermined level; and control means for controlling the mobile object based on the output of the determination means. monitoring equipment.