JP2005210334A - Communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem of a conventional wireless device that video data cannot be transmitted/received when the transmission/reception range of an antenna installed on a gondola deviates from the transmission/reception range of the antenna of a wireless device installed in a monitoring station. <P>SOLUTION: In a communication system for transmitting/receiving data between a base station wireless device and a wireless device mounted on the gondola of ropeway, at least one of the base station wireless device and the wireless device mounted on the gondola comprises a plurality of antennas having different transmission/reception range, and a section for switching reception of the antennas wherein the switching section switches reception depending on the strength of received field of the antenna. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a communication system, and more particularly to a communication system that transmits video data of a TV camera mounted on a mobile body to a base station.

  Conventionally, for example, when video data such as a TV camera mounted on a moving body such as a gondola is wirelessly transmitted to a station building such as a ropeway, it deviates from the transmission / reception range of the antenna by the slack of the rope, the intrusion path near the station building, There is a problem that data cannot be sent or received. This will be described with reference to FIGS. FIG. 4 shows a wireless device including a conventional antenna device having directivity. In FIG. 4, when adjusting the direction of the antenna, it is normal to point it in the direction where the electric field strength is strongest. The directional antenna 401 is driven by the antenna driving device 402. A reception signal 403 received by the antenna 401 is sent to the transmission / reception unit 404, where the input radio wave is detected and smoothed, and the electric field strength is converted to direct current and displayed on the display unit 406. Accordingly, when the antenna driving device 402 is driven while viewing the display unit 406, the strongest direction of the input radio wave can be known. Recently, a computer is often used as an antenna angle control device, and there is also a device for displaying electric field intensity graphically on a cathode ray tube or the like. Note that a video signal received by the antenna 401 is also appropriately processed by the transmission / reception unit 404, displayed on the display unit 407 as necessary, and used for monitoring or the like.

  On the other hand, this wireless device includes a TV camera 407, and video captured by the TV camera 407 is appropriately signal-processed and transmitted to a monitoring office or the like in another location via the transmission / reception unit 404 and the antenna 401. .

  Thus, a case where video data of a TV camera or the like is wirelessly transmitted to a station building such as a ropeway using a wireless device including the antenna device having directivity as described above will be described with reference to FIG. FIG. 5 is a schematic diagram for explaining the state of transmission of surveillance video on a ropeway. In FIG. 5, reference numeral 501 denotes a rope (cable track) for suspending a gondola (carrying device), and the gondola moves between the foot of the mountain and the summit along the rope 501. Reference numeral 502 denotes a wireless device (also referred to as a base station wireless device) installed at the foot of the mountain. For example, the wireless device shown in FIG. 4 is installed. Note that the wireless device 502 can also be placed on the mountaintop. Reference numerals 503-1 and 503-2 denote wireless devices mounted on the gondola. For example, wireless devices as shown in FIG. 4 are installed. Note that the wireless devices 503-1 and 503-2 are collectively referred to as a wireless device 503. Reference numeral 504 denotes a transmission / reception range of the wireless device 502 installed at the foot of the mountain, and 505-1 and 505-2 indicate transmission / reception ranges of the wireless devices 503-1 and 503-2 mounted on the gondola. Note that the radio device 502 and the radio device 503 have different transmission / reception ranges because the radio devices have different radio wave emission angles and radiated power. The radio device 502 installed at the foot of a mountain is connected to a distant gondola. In order to transmit and receive video data, it is common to use an antenna with higher directivity.

  Now, a case will be described in which the video of the camera taken by the gondola 503 is received by the directional antenna of the wireless device 502 installed at the foot of the mountain and the monitoring video is displayed on the display device. First, in order for the wireless device 503-1 installed in the gondola and the wireless device 502 installed in the foothill to transmit and receive, it is necessary that the transmission / reception ranges of both the wireless devices 502 and 503-1 overlap. Therefore, as shown in FIG. 4, the antennas 401 of both the wireless devices 502 and 503-1 are driven by the antenna driving device 402, and the orientation of the antenna 401 is adjusted so that video data is received in an optimal state. On the other hand, in order for the wireless device 503-2 installed in the gondola and the wireless device 502 installed in the foothill to transmit and receive, it is also necessary that the transmission / reception ranges of both the wireless devices 502 and 503-2 overlap. However, as is apparent from FIG. 5, when the antenna 401 is adjusted so that the transmission / reception ranges of the two wireless devices 502 and 503-1 overlap, the wireless device 502 installed at the foot of the mountain and the wireless device 503-2 installed at the gondola. In some cases, the transmission / reception ranges do not overlap. In particular, when a camera is installed in a plurality of gondolas or when the gondola is moving, transmission / reception of all the radio devices 503 and radio devices installed at the foot of a mountain (generally a monitoring place). It is impossible to overlap the range, and there is a problem that the monitoring video cannot be received.

  In addition, the wireless operation system of the crossing ropeway (see, for example, Patent Document 1) relates to a wireless operation system in which a driver who is on the carrier can operate, decelerate, and stop wirelessly from the carrier. The technology is described.

JP 2001-10486 A

  The wireless device described above has a problem that video data cannot be transmitted / received when the transmission / reception range of the antenna of the wireless device installed at the monitoring location deviates from the transmission / reception range of the antenna installed in the gondola.

  An object of the present invention is to provide a communication system capable of transmitting and receiving optimum video data from a wireless device mounted on a moving gondola.

  Another object of the present invention is to provide a communication system capable of transmitting and receiving optimum video data from a large number of moving gondola wireless devices.

  The present invention relates to a communication system for transmitting and receiving data between a base station radio apparatus and a radio apparatus mounted on a ropeway gondola, and at least one of the base station radio apparatus and the radio apparatus mounted on the gondola. The wireless device includes a plurality of antennas having different transmission / reception ranges and a switching unit that switches reception of the antenna, and the switching unit is configured to be switched according to the reception field strength of the antenna.

  Further, in the communication system of the present invention, the plurality of wireless devices include a depression angle antenna and a wide angle antenna, and the switching unit is configured to be able to switch between the depression angle antenna and the wide angle antenna.

  As described above, according to the present invention, since the video shot with the gondola moving the ropeway can be displayed on the display device at the monitoring place in an optimum state, it is possible to ensure the safety of the operation of the gondola, Since images from multiple gondola can be monitored simultaneously, there is an advantage that safety management of the entire ropeway can be performed.

  An embodiment of the present invention will be described with reference to FIG. In FIG. 1, 101 and 102 are antennas having directivity, the antenna 101 is a depression antenna, and the antenna 102 is a wide-angle antenna. This will be described later. Reference numerals 103 and 104 denote antenna driving devices for driving the antenna 101 and the antenna 102, 105 denotes a switching unit for switching the antenna 101 and the antenna 102, and 106 denotes a receiving unit. Video data from the antenna 101 or the antenna 102 is displayed. Is transmitted to the arithmetic processing unit 107 as appropriate. Reference numeral 108 denotes a display device. This operation will be described below.

  The radio wave input to the antenna 101 or 102 is input to the receiving unit 106 via the switching unit 105. The receiving unit 106 converts it into a DC voltage corresponding to the received signal strength. Since the conversion method is conventionally known, the description thereof is omitted here. The converted signal is input to the arithmetic processing unit 107 as an electric field strength signal. The direction in which the radio wave is received is output as an antenna directivity angle signal from the driving device 103 or 104 driving the antenna, and is input to the arithmetic processing unit 107. Since the method of detecting the direction, the form of the signal, and the like are well known in the art, the description thereof is omitted here. As the arithmetic processing unit 107, an arithmetic processing unit such as a microcomputer or a personal computer can be used. The arithmetic processing unit 107 takes in the electric field strength signal and the antenna directivity angle signal simultaneously or sequentially at intervals not affected by the time difference, and creates data corresponding to the antenna orientation signal and the electric field strength signal. Therefore, based on this data, the display device 108 converts the display format for display on the display device 108 and outputs it as the display device 108. On the other hand, for the display of image data, the radio wave input to either the depression antenna 101 or the wide-angle antenna 102 is subjected to video data processing required by the receiving unit 106 and the arithmetic processing unit 107, and a monitoring video is displayed on the display unit 108. Is displayed. In this embodiment, the display of the incident radio wave intensity display and the monitoring video on the display unit 108 is described as being switched to the same display device 108, but may be displayed separately.

  Here, the azimuth angle θ and the electric field strength L of the depression antenna 101 and the wide-angle antenna 102 will be described with reference to FIG. In FIG. 3, 301 indicates a characteristic curve indicating the relationship between the azimuth angle θ of the depression antenna 101 and the electric field strength L, and 302 indicates a characteristic curve indicating the relationship between the azimuth angle θ of the wide-angle antenna 102 and the electric field strength L. Indicates. As is clear from this figure, the depression antenna 101 has a narrow antenna opening, but has a strong electric field strength of the main radio wave, and thus it reaches far. Further, the wide-angle antenna 102 shows that the antenna has a wide radio wave opening, but the electric field strength of the main radio wave is weak and therefore does not reach too far.

  Next, a case where the wireless device shown in FIG. 1 is installed on a ropeway as shown in FIG. 2 will be described. In FIG. 2, 201 shows the radio | wireless apparatus shown in FIG. 1 installed in the Yamagata station. 202 indicates a transmission / reception range when the depression antenna 101 is used, and 203 indicates a transmission / reception range when the wide-angle antenna 102 is used. In addition, the same code | symbol is attached | subjected to the same thing as FIG. As shown in FIG. 2, a wireless device 201 installed at the foothill station of the ropeway is provided with a depression antenna 101 and a wide-angle antenna 102, and is configured to be switched and used by a switching unit 105. As is apparent from the characteristic curve of FIG. 3, the transmission / reception range of the wireless device 201 when the depression antenna 101 is used is 202, and the transmission / reception range of the wireless device 201 when the wide-angle antenna 102 is used is 203. Become. Therefore, when communicating with the wireless device 503-1 mounted on the gondola located far from the Sanroku station, using the depression antenna 101 and communicating with the gondola 505-2 near the Sanroku station, A wide-angle antenna 102 is used.

  Switching between the depression angle antenna 101 and the wide angle antenna 102 is performed by the switching unit 105. That is, the arithmetic processing unit 107 compares the electric field strength from the depression antenna 101 with the electric field strength from the wide-angle antenna 102, selects the antenna with the stronger electric field strength, and switches the switching unit with the selection signal. it can.

  With this configuration, when the gondola is located far from the foothill station, it enters the transmission / reception range 202 of the hooked antenna 101, so that good reception is possible. When the gondola is close to the foothill station, the transmission / reception of the hooked antenna 101 is performed. Since it is out of the range 202, the switching unit 105 switches to the wide-angle antenna 102. As a result, since the gondola enters the transmission / reception range 203 of the wide-angle antenna 102, good reception with the radio 201 can be performed. By switching between the angle antenna and the wide angle antenna according to the movement of the gondola in this way, it is possible to transmit uninterrupted image data between the wireless device at the Yamagata station and the wireless device installed in the gondola over the entire ropeway. An extremely superior system can be realized for monitoring purposes.

  In addition, although the said Example demonstrated the case where the radio | wireless apparatus shown in FIG. 1 was installed in the Yamagata station, the same effect is acquired even if it mounts in a gondola. The antenna driving devices 103 and 104 adjust the direction of the antenna so that communication with the gondola can be performed optimally. The antenna driving devices 103 and 104 are driven by the output of the arithmetic processing unit 107. It is also possible to adjust manually by (or the supervisor). Furthermore, in the above-described embodiment, a radio apparatus provided with two antennas has been described. However, it is possible to easily use two or more antennas depending on the length of the ropeway or installation conditions.

  Although the present invention has been described in detail above, the present invention is not limited to the embodiments of the communication system described herein, and can be widely applied to communication systems other than those described above. There is no.

It is a figure for demonstrating one Example of this invention. It is a figure for demonstrating one Example at the time of applying this invention to a ropeway. It is a characteristic curve figure which shows the characteristic of the antenna of this invention. It is a block diagram which shows an example of the conventional radio | wireless apparatus. It is a figure for demonstrating an example of the radio system adapted to the conventional ropeway.

Explanation of symbols

101: narrow-angle antenna, 102: wide-angle antenna, 103, 104: antenna driving unit, 105: switching unit, 106: receiving unit, 107: arithmetic processing unit, 108: display unit, 201, 502: wireless device, 202: 侠Angular antenna transmission / reception range, 203: wide-angle antenna transmission / reception range, 301: depression antenna characteristic curve, 302: wide-angle antenna characteristic curve, 501: cableway, 503: gondola.

Claims (1)

In a communication system that transmits and receives data between a base station wireless device and a wireless device mounted on a ropeway gondola, at least one of the base station wireless device and the wireless device mounted on the gondola is: A communication system, comprising: a plurality of antennas having different transmission / reception ranges; and a switching unit that switches reception of the antenna, wherein the switching unit is switched according to a reception electric field strength of the antenna.

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