JP4982238B2 - Satellite communication device - Google Patents

Description

  The present invention relates to a satellite communication device that communicates with an earth station via an artificial satellite.

  As shown in FIG. 5, a satellite communication system is known in which a HUB station 7 (master station) and a plurality of earth stations 8 (slave stations) communicate with each other via an artificial satellite 9 in the TDMA system. Yes. When each of the earth stations 8 is distinguished, it is described as the earth station 8A or the earth station 8B, and when not distinguished, it is described as the earth station 8. Further, although not shown, the earth station 8 and the HUB station 7 are configured by a satellite communication device for communicating with the artificial satellite 9 and a communication device for transmitting and receiving data via the satellite communication device.

  Conventionally, for example, as shown in FIG. 6A, the HUB station 7 transmits data to the earth station 8, and when the earth station 8 normally receives the data transmitted from the HUB station 7, a response signal is sent. What is transmitted to the HUB station 7 is known (see, for example, Patent Document 1). The earth station 8 described in Patent Document 1 is a VSAT station (Very Small Aperture Terminal).

Further, when the earth station 8 transmits a response signal to the HUB station 7, the HUB station 7 determines whether or not the response signal transmitted from the earth station 8 can be received. As shown in (B), measures such as re-sending to the earth station 8 that could not be received are taken. Note that the HUB station 7 cannot receive the signal because the frequency of the received signal is abnormal or the strength of the received signal is insufficient.
JP-A-10-126326 (FIGS. 2 and 5)

  However, if the HUB station 7 cannot receive the signal transmitted from the earth station 8, the HUB station 7 and the earth station 8 may not be able to communicate again. If it is not detected that the HUB station 7 cannot receive, there is a problem that it is not possible to find out that the communication between the HUB station 7 and the earth station 8 is abnormal. In addition, when communication between the HUB station 7 and the earth station 8 becomes abnormal, the cause of the abnormality is analyzed using a special test apparatus, and thus analysis work is a burden.

  The present invention has been made to solve the conventional problems, and it is possible to confirm an abnormality in communication with the earth station even in a situation where a signal transmitted from the earth station can be received, and to easily identify the cause of the abnormality. An object of the present invention is to provide a satellite communication device capable of performing the above.

The satellite communication device of the present invention includes a communication unit that receives a signal transmitted from one or more earth stations of a communication partner via a satellite, and the earth station that is received by the communication unit communicates with its own device. A quality data acquisition unit for acquiring quality data relating to signal quality including a frequency or a level of a signal used for the transmission, and an earth station identification for identifying the earth station of the communication partner when the signal received by the communication unit is demodulated A reception data acquisition unit that acquires reception data including information, a data processing unit that combines the reception data acquired by the reception data acquisition unit and the quality data acquired by the quality data acquisition unit, and the data processing unit wherein said earth station identification information from the synthesized composite data in correspondence with the quality data and a display unit for displaying by said quality data acquisition unit, the through Information indicating the level of the signal received by the unit and information indicating a frequency shift of the signal with respect to a predetermined reference frequency to the data processing unit, the received data acquisition unit, The earth station identification information is extracted from the received data and output to the data processing unit, the data processing unit is information indicating the level of the signal, information indicating a frequency shift of the signal, The synthesized data obtained by synthesizing the earth station identification information is output to the display unit, and the display unit provides information indicating the level of the signal and a frequency shift of the signal for each earth station identification information. And at least one of the level of the signal from the earth station identified by the earth station identification information and the frequency deviation of the signal is within a predetermined allowable range. It has a configuration is for displaying, and information indicating a.
With this configuration, the quality data consisting of the frequency shift and signal level of the signal received from the earth station and the earth station identification information are displayed in correspondence with each other, so that the earth signal can be received even when the signal transmitted from the earth station can be received. An abnormality in communication with a station can be confirmed, and the cause of the abnormality such as a signal frequency shift and a signal level can be easily identified, and reception statuses of a plurality of earth stations can be centrally monitored.

  The present invention can confirm an abnormality in communication with the earth station even in a situation where a signal transmitted from the earth station can be received, can easily identify the cause of the abnormality, and centrally monitors the reception state of a plurality of earth stations. The present invention provides a satellite communication device that enables this.

  Hereinafter, a satellite communication system and a satellite communication apparatus according to embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a satellite communication system according to an embodiment of the present invention.

  As shown in FIG. 1, a satellite communication system according to an embodiment of the present invention includes a plurality of earth stations 8 (child stations), and a HUB station 6 (master station) that centrally manages and controls these earth stations 8. , And an artificial satellite 9 that relays communication between the earth station 8 and the HUB station 6. In the satellite communication system according to the embodiment of the present invention, communication between the HUB station 6 and each earth station 8 is performed using a TDMA (Time Division Multiple Access) system.

  The HUB station 6 includes a satellite communication device 10 according to the embodiment of the present invention. The plurality of earth stations 8 (slave stations) are miniaturized and portable in accordance with, for example, VSAT. Although not shown, the earth station 8 includes a satellite communication device for communicating with the artificial satellite 9 and a communication device for transmitting and receiving data via the satellite communication device.

  FIG. 2 is a block diagram of the satellite communication apparatus 10 according to the embodiment of the present invention. The satellite communication apparatus 10 includes a demodulation processing unit 11 that demodulates a signal received from an antenna (not shown), a data processing unit 30 that processes demodulated data and quality data when the signal is demodulated, and quality data. It is comprised by the monitoring process part 40 to monitor.

  The quality data is data representing a level of a signal received by the satellite communication device 10 or a frequency shift of the signal. In addition, the satellite communication device 10 can transmit and receive signals when communicating with the artificial satellite 9, but for the convenience of explanation, members related to signal reception are mainly illustrated.

  The demodulation processing unit 11 includes an IF (Intermediate Frequency) receiving unit 12, an oscillator 13, a mixer 14, a band pass filter 15, a gain variable amplifier 16, a quadrature detector 17, an A / D converter 18, an FIR filter 19, and a D / D The A converter 20, the AGC control unit 21, the carrier clock recovery unit 22, and the data separation unit 23 are configured.

  A signal received by the antenna is input to the IF receiver 12, and the signal is output to the mixer 14. The oscillator 13 outputs a local oscillation signal with an oscillation frequency to the mixer 14.

  The mixer 14 converts the frequency of the signal output from the IF receiver 12 using the local oscillation signal output from the oscillator 13 and outputs the converted signal to the bandpass filter 15. The band pass filter 15 removes a specific frequency component from the signal frequency-converted by the mixer 14 and outputs the signal to the variable gain amplifier 16.

  The variable gain amplifier 16 amplifies the signal output from the bandpass filter 15 to a specified level, and the quadrature detector 17 demodulates the signal amplified by the variable gain amplifier 16 by quadrature detection and performs A / D. The data is output to the converter 18. The designated level is a level designated by the AGC control unit 21.

  The A / D converter 18 converts the signal output from the quadrature detector 17 into a digital signal, and the converted digital signal is waveform-shaped through the FIR filter 19, and the D / A converter 20 and the carrier clock recovery unit 22 is output.

  The D / A converter 20 converts the digital signal output from the FIR filter 19 into an analog signal and outputs the analog signal to the AGC control unit 21 and the data processing unit 30. The analog signal output from the D / A converter 20 is a control voltage used by the AGC control unit 21 and is information representing the level of the signal received by the satellite communication device 10. The signal level constitutes quality data.

  The AGC control unit 21 performs AGC (Automatic Gain Control), and adjusts the designated level so that the control voltage output by the D / A converter 20 becomes the reference voltage. The variable gain amplifier 16 amplifies the signal output from the bandpass filter 15 to a specified level, thereby keeping the average level of the signal output from the A / D converter 18 constant.

  The carrier clock reproduction unit 22 outputs the digital signal output from the FIR filter 19 to the data separation unit 23, reproduces the carrier from the digital signal, obtains the frequency of the received signal, and displays information indicating a deviation from the frequency. The data is output to the data processing unit 30. The frequency shift constitutes quality data. In the embodiment of the present invention, the frequency shift is represented by a relative value from the reference frequency.

  The data separation unit 23 processes the digital signal output from the carrier clock recovery unit 22 in accordance with a predetermined communication standard, and processes the digital signal in the header part data and the payload part data in accordance with the predetermined communication standard. And the data of the separated header portion is processed by the data separation portion 23, and the data of the payload portion is transferred to another member not shown.

  Further, the data separation unit 23 extracts the earth station identification information for identifying the earth station of the communication partner from the digital signal output by the carrier clock reproduction unit 22, and outputs the extracted earth station identification information to the data processing unit 30. It is like that.

  The data separation unit 23 may output information of the signal received together with the earth station identification information to the data processing unit 30. For example, the HUB station 6 periodically transmits a health check signal for confirming the communication state between the HUB station 6 and the earth station 8 to the earth station 8, and the earth station 8 receives the health check signal, A response signal for the received health check signal may be returned. In this case, when the satellite communication device 10 of the HUB station 6 receives the returned response signal, the data separation unit 23 can also output the response signal information to the data processing unit 30 together with the earth station identification information.

  In the embodiment of the present invention, the demodulation processing unit 11 constitutes the communication unit of the present invention, but the communication unit of the present invention is transmitted from one or more communication partner earth stations via a satellite. Any device that receives a signal may be used. The D / A converter 20 and the carrier clock recovery unit 22 constitute a quality data acquisition unit according to the present invention. The quality data acquisition unit according to the present invention acquires quality data related to signal quality. Anything can be used. The data separation unit 23 constitutes the reception data acquisition unit of the present invention, but the reception data acquisition unit of the present invention may be anything as long as it acquires reception data including earth station identification information.

  The data processing unit 30 includes an input / output interface 31, an SCI 32 (Serial Communication Interface), and a CPU 33 (Central Processing Unit). The input / output interface 31 receives quality data such as signal level and frequency shift, and the quality data is output to the CPU 33. Further, data such as earth station identification information is input to the SCI 32, and data such as earth station identification information is output to the CPU 33.

  The CPU 33 synthesizes the data such as the earth station identification information output from the SCI 32 and the quality data output from the input / output interface 31, and outputs the combined data to the monitoring processing unit 40. It should be noted that the CPU 33 synthesizes the earth station identification information and the quality data of the received signal in the order in which the signals transmitted from the earth station 8 are received.

  The CPU 33 may perform the synthesis process every time a signal transmitted from the earth station 8 is received. However, the CPU 33 performs the synthesis process only when a response signal to the health check signal is received. Also good. Note that the synthesized data may include a part or all of the digital signal processed by the data separation unit 23 in addition to the earth station identification information and the quality data.

  The monitoring processing unit 40 is connected to the data processing unit 30 via a LAN (Local Area Network) cable, for example, and performs communication with the data processing unit 30 in accordance with TCP / IP (Transmission Control Protocol / Internet Protocol). It is like that. The monitoring processing unit 40 includes an abnormality monitoring unit 41 and a display unit 42.

  The abnormality monitoring unit 41 is constituted by, for example, a CPU and outputs the combined data output by the data processing unit 30 to the display unit 42 and analyzes the combined data to determine an abnormality in communication with the earth station 8. It has become. For example, the abnormality monitoring unit 41 detects a communication abnormality by determining whether or not a deviation in the level or frequency of the signal constituting the quality data included in the synthesized data is within a predetermined allowable range. It has become. Further, the abnormality monitoring unit 41 may detect a communication abnormality when an event in which a deviation in signal level or frequency is within a predetermined allowable range continues for a predetermined number of times.

  The display unit 42 is configured by a display or the like, and displays the composite data output from the abnormality monitoring unit 41 on the screen. For example, the composite data displayed on the screen of the display unit 42 is displayed as shown in FIG. FIG. 3A is a display image when the composite data regarding the earth station 8A is displayed. FIG. 3B shows a display image when the synthesized data of the earth station 8B is displayed after the synthesized data of the earth station 8A is displayed. FIG. 3C is a display image when an abnormality is detected by the abnormality monitoring unit 41.

  An example of the operation of the satellite communication apparatus 10 configured as described above will be described below with reference to the drawings. FIG. 4 is a flowchart when the monitoring processing unit of the satellite communication apparatus 10 processes the composite data.

  First, the earth station identification information and the quality data representing the frequency shift and the signal level are synthesized by the data processing unit 30, and the synthesized data is inputted to the abnormality monitoring unit 41 (S1). Next, the abnormality monitoring unit 41 determines whether or not the frequency deviation is within a predetermined allowable range (S2).

  When the frequency deviation is within the predetermined allowable range, the abnormality monitoring unit 41 determines whether or not the signal level is within the predetermined allowable range (S3). When the signal level is within a predetermined allowable range, the abnormality monitoring unit 41 adds information indicating a normal state to the combined data and outputs the combined data to the display unit 42. The combined data is, for example, shown in FIG. The display unit 42 displays the image corresponding to the earth station 8B (S4).

  When the frequency shift is not within the predetermined allowable range in step S2, the abnormality monitoring unit 41 continuously generates the frequency shift within the predetermined allowable range at the earth station 8 of the earth station identification information for a predetermined number of times. It is determined whether or not (S5). If it is not continuously occurring a predetermined number of times that the frequency deviation is not within the predetermined allowable range, the process proceeds to step S3.

  When it is continuously occurring a predetermined number of times that the frequency deviation is not within the predetermined allowable range, the abnormality monitoring unit 41 adds the information indicating the abnormal state to the combined data and outputs it to the display unit 42, The synthesized data is displayed by the display unit 42 as an image corresponding to the earth station 8A in FIG. 3C, for example (S7).

  When the signal level becomes weak in step S3 and the signal level is not within the predetermined allowable range, the abnormality monitoring unit 41 determines that the signal level is within the predetermined allowable range at the earth station 8 of the earth station identification information. It is determined whether or not there is a predetermined number of times continuously (S6). If the signal level does not fall within the predetermined allowable range and does not occur a predetermined number of times, the process proceeds to step S4.

  When the signal level does not fall within the predetermined allowable range has occurred continuously a predetermined number of times, the abnormality monitoring unit 41 adds information indicating the abnormal state to the combined data and outputs the combined data to the display unit 42. The synthesized data is displayed by the display unit 42 as an image corresponding to the earth station 8A in FIG. 3C, for example (S7).

  Note that it is not necessary to perform steps S5 and S6. If the frequency shift is not within the predetermined allowable range in step S2, the combined data to which information indicating an abnormal state is added is displayed on the display unit 42 in step S7. Also good. Further, when the signal level is not within a predetermined allowable range in step S3, the combined data to which information indicating an abnormal state is added may be displayed on the display unit 42 in step S7.

  As described above, the satellite communication device 10 of the HUB station 7 displays the quality data including the frequency shift and signal level of the signal received from the earth station 8 in correspondence with the earth station identification information. Even in a situation where the signal transmitted from the station 8 can be received, an abnormality in communication with the earth station 8 can be confirmed, and an abnormality factor such as an abnormality in signal frequency deviation or an abnormality in signal level can be identified. The reception status of a plurality of earth stations 8 can be centrally monitored.

  In addition, the satellite communication device 10 of the HUB station 7 determines whether or not a value indicating a frequency shift or level is within a predetermined allowable range, thereby detecting a signal frequency shift error or a signal level error. Error detection accuracy because it is processed as a communication error when a value indicating a frequency deviation or level is not within a predetermined allowable range for a certain number of consecutive occurrences. Is increasing.

  As described above, the present invention has an effect of being able to confirm an abnormality in communication with the earth station and to identify the cause of the abnormality even in a situation where a signal transmitted from the earth station can be received. It is useful as a satellite communication device that communicates with the earth station via

1 is a block diagram of a satellite communication system according to an embodiment of the present invention. Block diagram of a satellite communication apparatus according to an embodiment of the present invention The figure showing the display image when the synthetic data regarding the earth station which concerns on embodiment of this invention is displayed The flowchart when the monitoring process part of the satellite communication apparatus which concerns on embodiment of this invention processes synthetic data Block diagram of a conventional satellite communication system Sequence diagram related to data transmission / reception in a conventional satellite communication system

Explanation of symbols

DESCRIPTION OF SYMBOLS 8 Earth station 6, 7 HUB station 9 Artificial satellite 10 Satellite communication apparatus 11 Demodulation processing part 12 IF receiving part 13 Oscillator 14 Mixer 15 Band pass filter 16 Gain variable type amplifier 17 Orthogonal detector 18 A / D converter 19 FIR filter 20 D / A converter 21 AGC control unit 22 Carrier clock recovery unit 23 Data separation unit 30 Data processing unit 31 Input / output interface 32 SCI
40 Monitoring processing part 41 Abnormality monitoring part 42 Display part

Claims (1)

A communication unit for receiving a signal transmitted from one or more communication partner earth stations via a satellite;
A quality data acquisition unit for acquiring quality data related to the quality of the signal including the frequency or level of the signal received by the communication unit and used by the earth station for communication with its own device;
A reception data acquisition unit for acquiring reception data including earth station identification information for identifying the earth station of the communication counterpart when a signal received by the communication unit is demodulated;
A data processing unit that combines the reception data acquired by the reception data acquisition unit with the quality data acquired by the quality data acquisition unit;
A display unit for displaying the earth station identification information and the quality data in correspondence with the synthesized data synthesized by the data processing unit ,
The quality data acquisition unit outputs information indicating a level of a signal received by the communication unit and information indicating a frequency shift of the signal with respect to a predetermined reference frequency to the data processing unit. Yes,
The received data acquisition unit extracts the earth station identification information from the received data and outputs it to the data processing unit,
The data processing unit outputs combined data obtained by combining the information indicating the level of the signal, information indicating a frequency shift of the signal, and the earth station identification information to the display unit,
The display unit includes, for each earth station identification information, information representing the level of the signal, information representing a frequency shift of the signal, and the level of the signal from the earth station identified by the earth station identification information. And a satellite communication device for displaying whether or not at least one of the frequency shifts of the signal is within a predetermined allowable range .

Images