JP6565562B2 - Information transmission program, information transmission method, and information transmission apparatus - Google Patents

Description

  The present invention relates to an information transmission program, an information transmission method, and an information transmission apparatus.

  Conventionally, a short wave having a frequency of 3 MHz to 30 MHz and a wavelength of 10 m to 100 m is used for communication between a land base station and a ship such as a fishing boat on the sea. Communication using short waves is performed using reflection by the ionosphere. For example, when confirming the safety of a fishing boat, when a base station such as a fishing port transmits a message, the message reflected by the ionosphere is received by a radio device mounted on the ship. Thereafter, when the wireless device transmits a response message for the message, the response message reflected by the ionosphere is received by the base station. In this way, the base station confirms the safety of the fishing boat.

Japanese Patent Laid-Open No. 10-294690

  However, short-wave communication is affected by natural phenomena because the bandwidth of the frequency that can be occupied is narrow and the reflection of the ionosphere is used. For this reason, a region where short waves do not reach (hereinafter sometimes referred to as a dead zone) occurs between the land base station and the marine vessel, and the safety of the vessel located in this region cannot be confirmed. Therefore, land base stations sometimes repeat transmission of telegrams by changing the frequency or the like, and shortwave communication is not efficient. This problem is not limited to ships, but there is a similar problem in areas where communication is difficult, such as deserts, mountainous areas, and depopulated areas. For example, there is a similar problem when confirming the safety of people or livestock in such difficult communication areas.

  In one aspect, an object is to provide an information transmission program, an information transmission method, and an information transmission apparatus capable of executing efficient shortwave communication.

  In the first plan, the information transmission program causes the computer to execute processing for acquiring an ionosphere map indicating the radio wave intensity between the positions at the time of wireless communication using the ionosphere at sea. The information transmission program causes the computer to execute processing for identifying the first ship that has succeeded in wireless communication and the second ship that has failed in wireless communication. The information transmission program causes the computer to execute a process of identifying a third ship that can communicate with the second ship from the first ship based on the ionosphere map. The information transmission program causes the computer to execute a process of relaying and transmitting a radio signal to the second ship with respect to the specified third ship.

  According to one embodiment, efficient shortwave communication can be performed.

FIG. 1 is a functional block diagram illustrating the configuration of the system according to the first embodiment. FIG. 2 is an explanatory diagram showing an example of a message format. FIG. 3 is a diagram illustrating an example of an ionosphere map. FIG. 4 is a diagram illustrating an example of area information. FIG. 5 is a diagram illustrating an example of information stored in the reception information DB. FIG. 6 is a diagram illustrating an example of the sea information map. FIG. 7 is a sequence diagram showing the flow of processing. FIG. 8 is a diagram illustrating a format example of a message. FIG. 9 is a flowchart showing a process flow of the base station. FIG. 10 is a diagram illustrating a transmission example of a broadcast message from the base station. FIG. 11 is a diagram illustrating a transmission example of an Ack message from each ship. FIG. 12 is a diagram illustrating an example of relaying a broadcast message. FIG. 13 is an explanatory diagram illustrating an example of a computer that executes an information transmission program.

  Embodiments of an information transmission program, an information transmission method, and an information transmission apparatus according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

[overall structure]
FIG. 1 is a functional block diagram illustrating the configuration of the system according to the first embodiment. The management system illustrated in FIG. 1 includes a management server 2, a plurality of ships 10, and a plurality of base stations 100. Note that the number of ships and base stations is not limited and can be arbitrarily changed.

  The communication terminals 11 and the plurality of base stations 100 included in each ship 10 are connected to each other so as to be able to communicate with each other by a short-band radio wave using the reflection of the ionosphere L. Further, the base stations 100 and the management server 2 are connected via a network N so that they can communicate with each other. For such a network N, any kind of communication network such as the Internet (Internet), LAN (Local Area Network), VPN (Virtual Private Network), etc. can be adopted regardless of wired or wireless.

  Here, the system according to the first embodiment will be described. In the following description, a fishing boat will be described as an example of a ship. In the management system, for example, the communication terminal 11 is installed in a ship 10 such as a fishing boat that operates in the ocean, at least 200 nautical miles away from the coast. Each base station 100 is installed in a fishery radio association or the like provided in the vicinity of a fishing port. In addition, the management system is provided with a management server 2 on a cloud such as a data center, for example, and is connected to each base station 100 via a network N. Moreover, in the example of FIG. 1, a certain base station is installed in Hokkaido, for example, and another base station is installed in Okinawa, for example. In addition, in FIG. 1, although the case where the base station 100 was installed in the fishery radio association was shown, it is not limited to this. Base station 100 may be installed alone or in another fishery radio association.

  For example, each base station 100 may be assigned a marine area to be managed. Each base station 100 is also installed in a coastal station or the like in the Fisheries Radio Association, and can also hold a list of ship IDs that identify ships to be managed.

  The management server 2 periodically collects the position information of the fishing boat via each base station 100 and generates a position map indicating the position of each fishing boat. In addition, the management server 2 collects the radio wave intensity when radio communication is performed between the fishing boats via the base stations 100, and the radio wave intensity between positions during radio communication using the ionosphere at sea. An ionosphere map showing is generated. For example, the management server 2 generates an ionosphere map for each combination of season, frequency, and time zone. The management server 2 can generate an ionosphere map in any combination such as an ionosphere map for each season and an ionosphere map for each combination of season and frequency.

  The management server 2 stores the position map and ionosphere map on a disk that can be shared with each base station 100. By doing in this way, each base station 100 can read a position map and an ionosphere map, and can preserve | save it in an own apparatus. The management server 2 updates the position map and ionosphere map each time information is acquired from the base station 100.

  Note that examples of situations in which reception is difficult include interference due to a fading phenomenon or the like, and occurrence of some errors. The fading phenomenon includes coherent fading, polarization fading, jump fading, absorptive fading, selective fading, and K-type fading. Coherent fading is fading caused by a path difference when there are a plurality of paths through which radio communication radio waves reach. Polarization fading is fading that occurs when the plane of polarization changes when radio waves are reflected on the ionosphere. Jumping fading is fading that occurs when radio waves are reflected by the ionosphere or penetrate through the ionosphere due to variations in the density of the ionosphere. Selective fading is fading that occurs when a band and an attenuation amount that are attenuated by a frequency selective medium in a radio wave transmission path vary with time. K-type fading is fading that occurs when the equivalent radius coefficient (K) of the earth fluctuates due to weather conditions or the like, and the bending of the radio wave transmission path fluctuates.

[Function configuration]
Next, functional configurations of the communication terminal 11 and each base station 100 included in the ship 10 illustrated in FIG. 1 will be described.

(Functional configuration of communication terminal 11)
As illustrated in FIG. 1, the communication terminal 11 includes a wireless unit 12, a storage unit 13, and a control unit 14, and is installed on the ship 10. Note that the communication terminal 11 may include various functional units included in known computers, for example, functional units such as various input devices and audio output devices, in addition to the functional units illustrated in FIG. 1. As an example of the communication terminal 11, a tablet terminal, a portable personal computer, or the like can be employed. The communication terminal 11 is a transmitter that transmits management information such as position information and radio wave intensity using short waves.

  The radio unit 12 is realized by, for example, a medium wave to short wave or ultra high frequency band radio device. The wireless unit 12 is wirelessly connected to any one or more of the plurality of base stations 100 via the ionosphere L, and performs communication of information with the management server 2 via the base station 100 and the network N. Interface. The radio unit 12 transmits the management information input from the control unit 14 toward the base station 100. The wireless unit 12 receives radio waves transmitted from the base station 100 and acquires various types of information.

  The radio unit 12 is one of at least one of a 2 MHz band, a 4 MHz band, an 8 MHz band, a 12 MHz band, a 16 MHz band, a 30 MHz band, and a 50 MHz band or more as a radio wave of medium to short wave or ultra high frequency band. A frequency band can be used. For example, the radio unit 12 uses a frequency band selected by the operator of the communication terminal 11 according to the distance from the land and the time zone. This is because the propagation state of radio waves in the medium wave, short wave band, and ultra short wave band is affected by the ionosphere, which varies in state depending on solar activity and day and night. In addition, the selection of the frequency calculates the distance to the representative base station 100 based on the position information obtained by positioning with a positioning sensor or the like, and weights each frequency according to the calculated distance, season and time. It is also possible to select a frequency that is more likely to reach. The frequency is selected in consideration of the band characteristics of each frequency band.

  The radio unit 12 can use digital modulation such as PSK (Phase Shift Keying) and FSK (Frequency Shift Keying) as a modulation method. In addition, the radio unit 12 can use a modulation scheme such as PSK31 in a low frequency band. For example, PSK31 has a low communication speed of 31 baud but has a narrow exclusive band and is suitable for data communication in a short wave band for mainly communicating text data. Note that the wireless unit 12 uses, for example, serial communication using RS-232C for control of the wireless unit 12 as a connection method with the control unit 14, and voice input / output for data exchange such as management information. A modulation signal can be input and output using a terminal.

  In addition, when using the existing radio device mounted on the ship 10, it is possible to separately install a modulation device for performing digital modulation in a short wave frequency band. In this case, when the digital information output from the control unit 14 is acquired, the digital information is modulated into an analog waveform and output to the wireless device. In addition, as the wireless unit 12, an existing wireless device mounted on a ship can be used.

  The storage unit 13 is realized by, for example, a semiconductor memory device such as a random access memory (RAM) or a flash memory, or a storage device such as a hard disk or an optical disk. The storage unit 13 stores various information included in the management information, information used for processing in the control unit 14, and the like.

  The storage unit 13 stores position information obtained by positioning, radio wave intensity measured when a radio signal is transmitted / received to / from another communication terminal 11, and the like. The storage unit 13 can also store various signals and various maps transmitted from the base station 100.

  The control unit 14 is realized, for example, by executing a program stored in an internal storage device using a RAM as a work area by a CPU (Central Processing Unit), an MPU (Micro Processing Unit), or the like. The control unit 14 may be realized by an integrated circuit such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA).

  The control unit 14 controls the entire communication terminal 11. The control unit 14 includes a position measurement unit 15, a response unit 16, and a relay unit 17.

  The position measurement unit 15 is a processing unit that receives a signal of the satellite positioning system. The position measuring unit 15 performs positioning by receiving signals from a global navigation satellite system such as GPS (Global Positioning System), GLONASS (Global Navigation Satellite System), Galileo, and a compass as a satellite positioning system. The position measuring unit 15 performs positioning when positioning is requested from the control unit 14, and outputs the positioning result as position information based on a geodetic system such as a WGS (World Geodetic System) 84. In addition, when the position measurement unit 15 is requested by the control unit 14 to continue positioning, the position measurement unit 15 continuously performs positioning and continues to output position information until the control unit 14 requests to stop. The position measurement unit 15 receives a signal from a quasi-zenith satellite system, an Indian regional navigation satellite system, DORIS (Doppler Orbitography and Radio-positioning Integrated by Satellite), and a regional navigation satellite system such as Hokuto as a satellite positioning system. May be.

  The response unit 16 is a processing unit that transmits various responses when a broadcast telegram is received. For example, the response unit 16 receives the broadcast message transmitted from the base station 100 when the destination of the received broadcast message is a broadcast address, or when the received broadcast message includes an identifier or the like indicating a safety confirmation inquiry. Is received directly. And the response part 16 produces | generates the response message containing Ack which shows having received normally, the positional information which shows the present position, etc., and transmits the produced | generated response message with respect to the base station 100 of a transmission origin.

  The relay unit 17 is a processing unit that relays a broadcast message to another ship when the broadcast message transmitted from the base station 100 to the other ship is received. For example, when the received broadcast message includes a ship ID for identifying a ship on which the terminal is mounted as a relay terminal and a ship ID (final destination ship) as a destination, the relay unit 17 transmits the broadcast ID from the base station 100. The relay instruction is determined.

  And the relay part 17 transmits the received broadcast message | telegram by using ship ID of a relay destination as a destination. Thereafter, when the relay unit 17 receives an Ack message from a communication terminal mounted on a relay destination ship, that is, a final destination ship, the relay unit 17 generates a response message including the Ack message and transmits it to the transmission source base station 100. To send. At this time, when the relay unit 17 receives position information and the like together with the Ack message from the destination ship, the relay unit 17 can also respond to the base station 100 with a response message including the received position information.

  Further, the control unit 14 periodically reads position information, radio wave intensity, and the like from the storage unit 13, generates management information including these pieces of information, and transmits the management information to the base station 100 via the wireless unit 12. .

  FIG. 2 is an explanatory diagram showing an example of a message format. As shown in FIG. 2, for example, the message format 21 includes “Char code”, “format ver”, “Message Type”, “name of a vessel”, “Call Sign”, “nationality”, “prefectures”, “ It has items such as “Geographic Point Location” and “Parity”. In the message format 21 in FIG. 2, for example, one cell is one byte. The length of the message format 21 shown in FIG. 2 is 104 bytes as an example, but is not limited to this, and can be an arbitrary length. Further, the message format 21 may include, as items, a wireless association code to be forwarded, a position information mask level indicating a level to mask a part of the position information, that is, an encryption level, and the like.

  “Char code” indicates a character code system. “Format ver” indicates the version of the message format 21 and is an item for responding to the format change. “Message Type” indicates a message type, for example, a message type such as automatic, manual, request transmission, or emergency. “Name of a vessel” represents the name or identification information of the fishing boat on which the communication terminal 11 is installed. Note that “name of a vessel” may represent the name and identification information of a fishing boat if the number of characters is sufficient. “Call Sign” represents the call sign of the radio station for reliable identification. “Nationality” is an abbreviation of “nationality registration” and represents a country of registration of a vessel. “Prefectures” represents the prefecture to which the affiliation belongs. “Geographic Point Location” indicates location information, and represents, for example, a positioning system, latitude, and longitude. “Parity” is a parity for confirming complete reception of the message.

  Further, the control unit 14 may use TCG (Trusted Computing Group) technology to make it possible to verify the authenticity of the information and to implement secure information transmission. Here, an example of the TCG technique will be described.

  Terminals and devices that communicate with the outside are always exposed to security threats, and unexpected modifications may be made to the software structure that constitutes the platform due to viruses, spyware, other malicious scripts, unauthorized access, and the like. For such risks, TCG realizes a safe computing environment by ensuring the reliability of the platform. Here, the platform indicates hardware, OS, application, and the like.

  For example, there is a limit to conventional security measures that depend on software against the threat of software tampering. For this reason, TCG embeds a TPM (Trusted Platform Module) chip (not shown) in the platform, and uses this TPM chip as a root of trust to construct a reliable computing environment that is extremely difficult to falsify. Further, by using the TPM chip, hardware-based data / certificate protection and a secure cryptographic processing environment can be realized.

  Next, the TPM chip will be described. The TPM chip is a birdware chip bound to an electronic device (for example, the communication terminal 11) and has tamper resistance. The TPM chip is physically bound to the main components of the electronic device so that it cannot be removed from the electronic device. For example, the component parts of the electronic device correspond to a motherboard or the like. Since the TPM chip is designed with the functions, memory area, and processor power to be suppressed as much as possible, it can be manufactured at low cost and can be applied to various electronic devices and platforms.

  For example, the functions of the TPM include a function for generating and storing an RSA (Rivest Shamir Adleman) secret key, and a function for signing, encrypting, and decrypting with an RSA secret key. In RSA, a pair of a private key and a public key is created. In addition, the functions of the TPM include a function for performing a hash calculation of SHA-1 (Secure Hash Algorithm 1) and a function for holding environment information of the electronic device. When the bound electronic device is activated, the TPM measures the software code in the boot process to the BIOS, OSloader, and OS kernel, hashs the measured software code, and registers it in a register inside the TPM. Further, the TPM collects hardware information of the bound electronic device, hashes the hardware information, and registers the hashed information in a register in the TPM.

  In the TCG technology, a software stack and a software interface are defined in order to use a TPM chip that is a hardware device from a higher-level application or library. This software stack is called TSS (TCG Software Stack), and is composed of software modules that store the functions of TPM chips whose resources are limited. The application of the electronic device can access the function of the TPM chip described above using the interface provided by the TSS. The TPM chip ensures the validity of hash value collection by managing the rules for collecting hash values with the TPM chip on the customer system side by hashing and adding a signature. Moreover, the TPM chip proves the non-falsification of the rule by checking the current rule and signature as necessary. In other words, it is possible to verify the authenticity of the processing and information relating to the control unit 14. As a result, the TPM chip ensures that there is no falsification in the rules for collecting hash values by referring to the rules that have been proven to be non-falsified on the TPM chip side.

  In addition, the control unit 14 may insert information that has been hashed and signed by the TPM chip into a message format to generate a message that is management information. In this case, it is possible to verify the authenticity of processing and information related to the control unit 14 in the device (for example, the device in the fishery radio association to which the ship 10 belongs) that has received the generated electronic message.

(Functional configuration of base station 100)
As shown in FIG. 1, the base station 100 includes a communication unit 101, a storage unit 102, and a control unit 110, and is installed in a coastal station or the like. Note that the base station 100 may include various functional units included in known computers, for example, functional units such as various input devices and audio output devices, in addition to the functional units illustrated in FIG. The base station 100 has, for example, a radio for each frequency band, and an antenna (not shown) is connected to each radio, and communicates with the communication terminals 11 installed on a plurality of fishing boats simultaneously in each frequency band Can do.

  The communication unit 101 is realized by, for example, a medium wave, short wave, or ultra high frequency band radio device. The communication unit 101 is realized by, for example, a NIC (Network Interface Card) in order to communicate with the management server 2 via the network N. The communication unit 101 is wirelessly connected to any one or more of the plurality of communication terminals 11 via the ionosphere L, and is connected to the management server 2 via the network N. That is, the communication unit 101 is a communication interface that manages information communication between the communication terminal 11 and the base station 100 and between the base station 100 and the management server 2. That is, the base station 100 relays communication between the communication terminal 11 and the management server 2. The communication unit 101 connects to the network N by wire or wireless.

  The communication unit 101 is, for example, a plurality of wireless devices, for example, 2 MHz band, 4 MHz band, 8 MHz band, 12 MHz band, 16 MHz band, 30 MHz band, and 50 MHz band or more, as a radio wave of medium to short wave or ultra high frequency band. The radio waves transmitted from the communication terminal 11 are received using seven wireless devices corresponding to the ultra high frequency band. The communication unit 101 receives radio signals transmitted from the plurality of communication terminals 11 using radio waves having different frequencies, with a plurality of radio devices having corresponding frequencies. In addition, the frequency band to be used is determined according to any one or more of the position and time slot | zone of the fishing boat in which the communication terminal 11 is installed. Further, the communication unit 101 uses the same modulation scheme as the radio unit 12 of the communication terminal 11 as the modulation scheme. In addition, the communication unit 101 can use the serial communication using RS-232C and the data communication using the voice input / output terminal similarly to the communication terminal 11 for connection to the control unit 110. When using an existing radio installed in the base station, it is possible to separately install a modulation device for performing digital modulation in a short wave frequency band. In this case, when the analog waveform received by the wireless device is acquired, the analog waveform is converted into digital information and output to the control unit 110.

  The communication unit 101 extracts management information from the received radio wave, that is, a message, and outputs the management information to the control unit 110. The communication unit 101 transmits the extracted management information to the management server 2 via the network N using the NIC.

  The storage unit 102 is realized by, for example, a semiconductor memory device such as a RAM or a flash memory, or a storage device such as a hard disk or an optical disk. The storage unit 102 stores information used for processing in the control unit 110, and also stores an ionosphere map DB 103, a reception information DB 104, and a sea information map 105. Moreover, the memory | storage part 102 memorize | stores the positional information received regularly from the communication terminal 11 of each ship in time series. That is, it is possible to estimate the current position of a ship by specifying the position information stored in the storage unit 102 in time series. Also, the ionosphere map is updated by storing the data (logs) recorded during the voyage (including communications of other ships) in the DB of the management server or the like via a memory or by high-speed communication such as a mobile phone when calling at the port. it can.

  The ionosphere map DB 103 is a database that stores an ionosphere map for each combination of a season, a frequency, and a time zone. Each ionosphere map is generated by the management server 2, and is read from the management server 2 by the control unit 110 and stored in the ionosphere map DB 103. That is, the ionosphere map DB 103 stores an ionosphere map of each region that is managed by the base station 100.

  FIG. 3 is a diagram illustrating an example of an ionosphere map. The ionosphere map shown in FIG. 3 is generated based on the results measured when the season is S, the frequency is fa, and the time zone is 00:00 to 01:00.

  In the example of FIG. From "001003" to Area No. Indicates that the radio wave intensity is “0.62” in the wireless communication between “001002”. That is, when the season is S and the time zone is from 00:00 to 01:00, a message is transmitted and received between the ship located at “001003” and the ship located at “001002” using the frequency fa. It shows that the radio wave intensity was “0.62.” Note that there are communication from “001003” to “001002” and communication from “001002” to “001003”, and either one is adopted here. Also, the average value of both radio field intensities can be adopted.

  In the example of FIG. 3, an example is shown in which the higher the numerical value, the better the radio wave intensity. However, the present invention is not limited to this, and various indexes can be adopted. For example, the success rate and error rate of wireless communication, and the average values of the past several times can also be employed. That is, various indexes indicating the stability of wireless communication using the ionosphere can be employed.

  The ionosphere map DB 103 also stores area information in which the ionosphere map area and the actual position are associated with each other. FIG. 4 is a diagram illustrating an example of area information. As shown in FIG. 4, the ionosphere map DB 103 stores “Area No.” that specifies an area in the chart and “center position” that indicates the center of the area in association with each other. In the example of FIG. Indicates that the region identified by “001001” is within a circle having a radius of 10 km centered on “N12 ° 14 ′ 36 ″, E139 ° 32 ′ 45 ″”.

  Here, an example in which regions are distinguished by circles has been described, but the present invention is not limited to this. For example, each area may be associated with four positions, and each area may be an area surrounded by four points. Alternatively, two areas may be associated with each area, and each area may be a region surrounded by a circle having a diameter of two points.

  The reception information DB 104 is a database that stores the reception status of broadcast telegrams transmitted from the base station 100. That is, the reception information DB 104 stores information indicating whether or not each ship under the management of the base station 100 has been received for each broadcast message transmitted by the base station 100.

  FIG. 5 is a diagram illustrating an example of information stored in the reception information DB 104. As shown in FIG. 5, the reception information DB 104 stores “broadcast ID, ship ID, reception result, reception intensity (base, ship), time, position information, frequency” in association with each other.

  The “broadcast ID” stored here is an identifier for identifying a broadcast telegram, and the “ship ID” is an identifier for identifying a ship. The “reception result” indicates the reception status of the broadcast message, and “OK” is set when the broadcast message is received normally, and “NG” is set when the message cannot be received within a predetermined time. “Reception strength (base, ship)” indicates the downlink reception intensity from the base station 100 to the ship and the uplink reception intensity from the ship to the base station 100. “Time” indicates the time when the response message (Ack) is received from the ship, “Position information” is information indicating the position of the ship included in the response message, and “Frequency” indicates transmission of the broadcast message Indicates the frequency used.

  The example of FIG. 5 is the reception status of the broadcast message with the broadcast ID “B01” distributed using the frequency “8 MHz”. The ship with the ship ID “S01” is normally received and the ship ID is “S02”. Indicates that no response message has been received from the ship. Further, from the ship with the ship ID “S01”, a response message including the reception intensity (5, 5) and the position information (N12 ° 14 ′ 36 ″, E139 ° 32 ′ 45 ″) is “10:00: "00" indicates that it has been received.

  The sea information map 105 is a sea position map showing the position of the ship and the state of the sea. The information stored here is generated based on the ship position information periodically acquired by the base station 100 and the ship position information stored in the reception information DB 104 by the update unit 115 and the like to be described later. FIG. 6 is a diagram illustrating an example of the sea information map. As shown in FIG. 6, the sea information map 105 is information indicating the positions of the respective base stations “A point”, “B point”, “C point”, “D point”, and the position of each ship. It is. It is also possible to further illustrate the wave height, the direction of the wind, the traveling direction of each ship, and the like.

  The control unit 110 is realized by executing a program stored in an internal storage device using the RAM as a work area by a CPU, an MPU, or the like. The control unit 110 may be realized by an integrated circuit such as an ASIC or FPGA, for example. The control unit 110 includes a message transmission / reception unit 111, an error detection unit 112, a relay identification unit 113, a relay instruction unit 114, and an update unit 115, and realizes or executes functions and operations of information processing described below. Note that the internal configuration of the control unit 110 is not limited to the configuration illustrated in FIG. 1, and may be another configuration as long as the information processing described below is performed.

  The message transmission / reception unit 111 is a processing unit that transmits a message such as a broadcast message to each ship and receives a response of the message from each ship. Then, the message transmission / reception unit 111 stores information in the reception information DB 104 according to the reception status.

  For example, the message transmission / reception unit 111 assigns a broadcast ID “B01” to a broadcast message for confirming safety. Then, the telegram transmitting / receiving unit 111 transmits the broadcast telegram having the broadcast ID “B01” by broadcast using the frequency “8 MHz”. After that, when receiving a response message from the ship with the ship ID “S01” at 10:00: 00 within a predetermined time such as 10 minutes, the message transmission / reception unit 111 receives the received strength (5, 5) from the response message. The position information (XXX) is extracted. The message transmission / reception unit 111 then associates the broadcast ID “B01” with “ship ID: S01, reception result: OK, reception intensity: 5, 5, position information: XXX, time: 10:00:00, frequency. : 8 MHz "is stored in the reception information DB 104.

  In addition, when the message transmission / reception unit 111 cannot receive a response message from the ship with the ship ID “S02” within a predetermined time such as 10 minutes, for example, the message transmission / reception unit 111 associates the broadcast ID “B01” with “ship ID: S02, reception”. “Result: NG, Frequency: 8 MHz” is stored in the reception information DB 104.

  The error detection unit 112 is a processing unit that refers to the reception information DB 104 and detects a ship that has not received a broadcast telegram. For example, the error detection unit 112 refers to the reception information DB 104 and identifies the broadcast ID “B01” with NG in the reception result. Then, the error detection unit 112 identifies the ship ID “S02” whose reception result is NG.

  That is, the error detection unit 112 detects that the ship with the ship ID “S02” is not received for the broadcast telegram with the broadcast ID “B01”. That is, the error detection unit 112 determines that the ship with the ship ID “S02” is located in the dead zone and the broadcast message has not arrived. Thereafter, the error detecting unit 112 notifies the relay specifying unit 113 of the specified broadcast ID “B01” and the ship ID “S02”, and requests retransmission of the corresponding broadcast message.

  The relay specifying unit 113 is a processing unit that specifies a ship that requests a broadcast telegram to be relayed. That is, the relay identifying unit 113 selects a ship that relays a broadcast message to be retransmitted from among ships located in the sensitive zone where the broadcast message arrives in order to deliver the broadcast message to the ship located in the dead zone where the broadcast message does not reach. Identify.

  For example, it is assumed that the relay identification unit 113 receives the broadcast ID “B01” and the ship ID “S02” from the error detection unit 112. That is, it is assumed that the ship with the ship ID “S02” cannot receive the broadcast message with the broadcast ID “B01”. In the following, in order to simplify the description, the ship with ship ID “S02” is received as “error ship”, the broadcast message with broadcast ID “B01” is received as “target message”, and the broadcast message with broadcast ID “B01” is received. Each completed ship will be described as “candidate ship”.

  In this case, the relay specifying unit 113 extracts the latest position information of the error ship from the position information of each ship stored in the storage unit 102. Also, the relay identification unit 113 refers to the reception information DB 104 and extracts the position information of the candidate ship whose reception result of the target message is “OK”. And the relay specific | specification part 113 specifies the area where each ship is located from the position information of the specified error ship and candidate ship according to the area information memorize | stored in ionosphere map DB103.

  Thereafter, the relay identification unit 113 reads from the ionosphere map DB 103 an ionosphere map that matches the season, time zone, and frequency at which the target message is distributed. And the relay specific | specification part 113 specifies the area with the highest radio wave intensity with the area where an error ship is located among the areas where each candidate ship is located according to an ionosphere map. Thereafter, the relay identification unit 113 identifies candidate ships located in the identified area as relay request destinations. Then, the relay identification unit 113 outputs information on the target message, the relay request destination ship, and the error ship to the relay instruction unit 114.

  For example, in FIG. 3, it is assumed that the area where the error vessel is located is “001005” and the areas where the candidate vessel is located are “001001”, “001002”, and “001004”. In this case, the relay identifying unit 113 has radio field strengths between “001005” and “001001” of “0.63”, and radio field strengths between “001005” and “001002” of “0.89” and “001005”. And “001004” is specified as “0.95”. As a result, the relay specifying unit 113 determines the candidate ship located at “001004” having the highest radio wave intensity as the relay request destination.

  Here, the relay identification unit 113 can estimate the position of the error vessel using various methods. For example, the relay specifying unit 113 specifies the speed of the error ship from the latest position information of the error ship and the previous position information. And the relay specific | specification part 113 can also estimate the present position of an error ship from the speed of an error ship and the newest position information of an error ship.

  Further, the relay specifying unit 113 specifies the traveling direction of the error ship from the latest position information of the error ship and the previous position information. Further, the relay specifying unit 113 calculates a time difference from the current time and the time when the latest position information of the error vessel is acquired. Further, the relay specifying unit 113 specifies a moving distance indicating how much the moving time is calculated with the calculated time difference from the past position information of the error vessel. And the relay specific | specification part 113 can also estimate the present position of an error ship in the advancing direction of an error ship from the newest position information of an error ship by the movement distance.

  Further, the relay identification unit 113 can also estimate the current position of the error vessel using both the speed and the traveling direction of the error vessel. Also, the relay specifying unit 113 can use two pieces of position information at different times instead of the latest position information and the previous position information. In this case, the relay specifying unit 113 can also estimate the speed and the like from the time difference and the moving distance.

  The relay instruction unit 114 is a processing unit that transmits a relay instruction to an error ship to a ship that has been determined as a relay destination. Specifically, the relay instruction unit 114 receives the relay request destination ship ID, the error ship's ship ID, and the broadcast ID of the target message from the relay specifying unit 113. Then, the relay instruction unit 114 adds the broadcast ID to the header, sets the corresponding message in the payload, sets the ship ID of the error ship as the final destination, and sets the ship ID of the relay request destination as the relay request destination. Generate a message.

  And the relay instruction | indication part 114 transmits the produced | generated relay telegram using the same frequency as the broadcast telegram transmitted initially. After that, when receiving a response message from the final destination error vessel via the relay request destination vessel, the relay instruction unit 114 updates the reception information DB 104. On the other hand, if the relay instruction unit 114 cannot receive a response message from the final destination error vessel, the relay instruction unit 114 outputs an instruction to specify another relay request destination to the relay specification unit 113 again. At this time, the relay instruction unit 114 repeats a predetermined number of times until a normal response can be received.

  The update unit 115 is a processing unit that updates the sea information map 105 according to the position information received from each ship and the reception status stored in the reception information DB 104. For example, the update unit 115 reflects the latest position of each ship on the sea information map 105 according to the received position information, and reflects the dead zone and the sensitive band on the sea information map 105 according to the received information DB 104.

[Sequence Diagram]
Next, a processing sequence executed by the management system shown in FIG. 1 will be described. FIG. 7 is a sequence diagram showing the flow of processing. Here, as an example, it is assumed that the management targets of the base station 100 are the ship A, the ship B, and the ship C. Moreover, although each ship has the communication terminal 11 demonstrated in FIG. 1, a code | symbol may be abbreviate | omitted and described here.

  As shown in FIG. 7, the management server 2 generates an ionosphere map using the radio wave intensity of the wireless communication received from the ship 10 (S101). The update unit 115 of the base station 100 acquires the ionosphere map from the management server 2 and stores it in the ionosphere map DB 103 (S102 and S103).

  The telegram transmitting / receiving unit 111 of the base station 100 generates a broadcast telegram and transmits it to the ship A, the ship B, and the ship C (S104 to S107). At this time, it is assumed that the broadcast message does not reach the ship B. Here, a format example of a broadcast message will be described. FIG. 8 is a diagram illustrating a format example of a message. As shown in FIG. 8, the broadcast telegram has “communication format information, base station ID, broadcast ID, broadcast information”. The “communication format information” is information indicating, for example, a character code system, a message format version, a message type, and the like. The “base station ID” is an identifier that identifies the source base station. “Broadcast ID” is an identifier for identifying a broadcast telegram. “Broadcast information” is the content of a broadcast message.

  Thereafter, the communication terminal of the ship A that has received the broadcast message transmits the Ack message to the base station 100 (S108 and S109). Similarly, the communication terminal of the ship C that has received the broadcast message also transmits the Ack message to the base station 100. (S110 and S111).

  And the error detection part 112 of the base station 100 detects the ship B as an error ship according to the reception condition of the Ack message from each ship (S112). Subsequently, the relay specifying unit 113 of the base station 100 specifies the positions of the ship A and the ship C according to the Ack message, and determines the position and traveling direction of the ship B received last time or an area where it is difficult to communicate with the current base station. Obtained from the ionosphere map information, the current position of the error vessel is estimated (S113).

  Thereafter, the relay identification unit 113 of the base station 100 identifies the relay request destination ship according to the position of each ship and the ionosphere map (S114). Here, it is assumed that the ship C is specified as the relay request destination ship.

  Subsequently, the relay instruction unit 114 of the base station 100 sets the ship B of the error ship as the destination and the ship C as the relay request destination, and generates a relay message including the content of the broadcast message in error (S115). , It transmits toward the ship C (S116 and S117).

  Here, a format example of the relay message will be described. As shown in FIG. 8, the relay telegram includes “communication format information, base station ID, broadcast ID, relay ship ID, destination ship ID, broadcast information”. Since “communication format information”, “base station ID”, “broadcast ID”, and “broadcast information” are the same as the broadcast telegram, description thereof is omitted. “Relay ship ID” is an identifier of a ship to be relayed, and the communication terminal of each ship specifies that its own apparatus is a relay ship when this relay ship ID is its own ID. “Destination ship ID” is an identifier of a ship that is the final destination, and corresponds to an identifier of an error ship. By designating the same broadcast ID as the broadcast message, it is possible to identify which broadcast message is to be retransmitted.

  And the communication terminal of the ship C will relay the received relay message with respect to the ship B of the destination set to a relay message, if a relay message is received (S118 and S119). When the communication terminal of the ship B receives the relay message from the ship C, the communication terminal transmits an Ack message to the ship C (S120 and S121). Thereafter, the communication terminal of the ship C transmits the Ack message received from the ship B to the base station 100 (S122 and S123).

[Base station processing]
FIG. 9 is a flowchart showing a process flow of the base station. As shown in FIG. 9, the telegram transmitting / receiving unit 111 of the base station 100 generates a telegram (S201), and transmits the generated telegram by broadcast (S202).

  After that, when receiving the Ack message from each ship (S203), the message transmission / reception unit 111 determines whether the end condition is satisfied (S204). The termination condition includes whether the number of retransmissions exceeds a threshold, whether the time for performing this processing is outside a specified time, or whether the number of Ack responses from the ship is equal to or greater than the threshold.

  Then, when it is determined that the termination condition is satisfied (S204: Yes), the update unit 115 updates the sea information map 105 using the received status information, reception status such as an Ack message, and the like (S205).

  On the other hand, when it is determined that the termination condition is not satisfied (S204: No), the relay identification unit 113 identifies the position of the error vessel (S206). Subsequently, the relay identifying unit 113 identifies the relay ship using the ionosphere map (S207). Thereafter, the relay instruction unit 114 generates a relay message including information requesting the relay vessel to relay to the error vessel and the content of the transmission target (S208), and transmits the relay message to the error vessel ( S209). Thereafter, S203 and subsequent steps are repeated.

[Concrete example]
Next, a specific example will be described with reference to the charts of FIGS. 10 is a diagram illustrating an example of transmission of a broadcast message from a base station, FIG. 11 is a diagram illustrating an example of transmission of an Ack message from each ship, and FIG. 12 is a diagram illustrating an example of relaying a broadcast message. It is.

  As shown in FIG. 10, base stations 100 are installed at points A, B, C, and D, respectively. Each base station 100 transmits the same broadcast telegram while suppressing interference using different frequencies. For example, the base station 100 at the point A transmits a broadcast signal to each ship including the ship A located in the sensitive zone and the ship B located in the dead zone.

  Thereafter, as shown in FIG. 11, when each ship receives a broadcast signal from any of the base stations 100, it responds with an Ack message to the base station 100 that is the transmission source. Here, since the ship A in the wireless range of the base station 100 at the point A is located in the sensitive zone, it can receive a broadcast message and can also respond to an Ack message. However, since the ship B in the wireless range of the base station 100 at the point A is located in the dead zone, it cannot receive the broadcast message and cannot respond to the Ack message.

  Therefore, as shown in FIG. 12, the base station 100, according to the ionosphere map, selects the ship A having the strongest radio wave intensity between the ship that can receive the Ack message and the position of the ship B that cannot receive the Ack message. Is identified. Then, the base station 100 requests the ship A to relay the broadcast message in error to the ship B. In this way, the base station 100 can transmit a telegram to the ship B located in the dead zone without repeating unnecessary retransmissions.

[effect]
As described above, the base station 100 can identify the sensitive zone and the dead zone from the reception status of the response message (Ack) and the ionosphere map, and can communicate with the vessel located in the dead zone among the vessels located in the sensitive zone. Identify the ship as a relay point. Then, the base station 100 requests the ship specified as the relay point to relay the message to the ship located in the dead zone. By doing in this way, the base station 100 can improve the message | telegram arrival rate to the ship located in a dead zone.

  Further, although the sensitive zone and dead zone vary depending on the season, time, frequency, natural environment, etc., the base station 100 can determine a ship as a relay point using an ionosphere map that is updated as appropriate. It can follow changes in the belt and dead zone. As a result, the base station 100 can improve the message arrival rate to the ship located in the dead zone without depending on the occurrence position of the dead zone or the dead zone.

  In addition, using a device that is connected to a conventional shortwave wireless device, such as a personal computer, digital data is placed on analog data for automatic transmission / reception, and transmission / reception of various information can be confirmed and recorded. As a result, a reliable and stable network at sea is possible, and the situation at sea can be shared between land and ship. Furthermore, the information received at each base station is centrally managed, recorded if received at any of the base stations, and the DB can be shared to improve accuracy and take measures against interference.

  Although the embodiments of the present invention have been described so far, the present invention may be implemented in various different forms other than the embodiments described above.

  Moreover, in the said Example, although the antenna connected to the communication part 101 of the base station 100 was each connected for every radio | wireless machine, it is not limited to this. For example, a multi-band antenna or an antenna tuner may be used. Further, different frequencies may be used for transmission from the ship to the land and transmission from the land to the ship. Thereby, the conditions of the antenna installation location are eased.

  Moreover, in the said Example, although PSK31 was mentioned as an example of digital modulation, it is not limited to this. For example, narrowband digital modulation that can be used in a short wave band such as RTTY (Radioteletype), packet communication, and SSTV may be used. Accordingly, communication with a larger amount of data can be performed in a high frequency band in the short wave band.

  In the above embodiment, the description has been given by taking the sea as an example. However, the present invention is not limited to this. Can do. In addition, the present invention can be similarly applied to communication difficult areas such as deserts, mountainous areas, and depopulated areas.

  For example, the base station 100 places a radio device in a private house, livestock, or the like that exists in an area where communication is difficult, and identifies the sensitive zone and dead zone from the reception status of the response message (Ack) and the ionosphere map. And base station 100 specifies the radio | wireless machine which can communicate with the radio | wireless machine located in a dead zone among the radio | wireless machines located in a dead zone as a relay point. Then, the base station 100 can request the radio device specified as the relay point to relay the message to the radio device located in the dead zone.

[Resending method]
In the above embodiment, when a relay telegram is transmitted, an example in which the relay telegram is transmitted at the same frequency as the first broadcast telegram has been described. However, the present invention is not limited to this. For example, it is possible to transmit by changing the frequency. In that case, the base station 100 can determine the ship which becomes a relay point using the ionosphere map corresponding to the changed frequency.

[system]
In addition, each component of each part illustrated does not necessarily need to be physically configured as illustrated. In other words, the specific form of distribution / integration of each unit is not limited to that shown in the figure, and all or a part thereof may be functionally or physically distributed / integrated in arbitrary units according to various loads or usage conditions. Can be configured. Furthermore, various processing functions performed by each device may be executed entirely or arbitrarily on a CPU (or a microcomputer such as an MPU or MCU (Micro Controller Unit)). In addition, various processing functions may be executed in whole or in any part on a program that is analyzed and executed by a CPU (or a microcomputer such as an MPU or MCU) or on hardware based on wired logic. Needless to say, it is good.

[hardware]
The various processes described in the above embodiments can be realized by executing a prepared program on a computer. Therefore, in the following, an example of a computer that executes a program having the same function as in the above embodiment will be described. FIG. 13 is an explanatory diagram illustrating an example of a computer that executes an information transmission program.

  As illustrated in FIG. 13, the computer 200 includes a CPU 201 that executes various arithmetic processes, an input device 202 that receives data input, and a monitor 203. The computer 200 also includes a medium reading device 204 that reads a program and the like from a storage medium, an interface device 205 for connecting to various devices, and a communication device 206 for connecting to other information processing devices and the like by wire or wirelessly. Have The computer 200 also includes a RAM 207 that temporarily stores various types of information and a hard disk device 208. Each device 201 to 208 is connected to a bus 209.

  The hard disk device 208 stores a communication control program having the same functions as the processing units of the message transmission / reception unit 111, the error detection unit 112, the relay identification unit 113, the relay instruction unit 114, and the update unit 115 illustrated in FIG. The The hard disk device 208 stores an ionosphere map DB 103, a reception information DB 104, a sea information map 105, and various data for realizing an information communication program. The input device 202 receives input of various information such as operation information from the administrator of the computer 200, for example. The monitor 203 displays various screens for the administrator of the computer 200, for example. The interface device 205 is connected to, for example, a printing device. The communication device 206 has the same function as the communication unit 101 illustrated in FIG. 1 and is connected to the network N, for example.

  The CPU 201 reads out each program stored in the hard disk device 208, develops it in the RAM 207, and executes it to perform various processes. In addition, these programs can cause the computer 200 to function as the message transmission / reception unit 111, the error detection unit 112, the relay identification unit 113, the relay instruction unit 114, and the update unit 115 illustrated in FIG.

  Note that the information communication program is not necessarily stored in the hard disk device 208. For example, the computer 200 may read and execute a program stored in a storage medium readable by the computer 200. The storage medium readable by the computer 200 corresponds to, for example, a portable recording medium such as a CD-ROM, a DVD disk, a USB (Universal Serial Bus) memory, a semiconductor memory such as a flash memory, a hard disk drive, and the like. Alternatively, the information communication program may be stored in a device connected to a public line, the Internet, a LAN, etc., and the computer 200 may read and execute the management program from these.

2 management server 10 ship 11 communication terminal 12 wireless unit 13 storage unit 14 control unit 15 position measurement unit 16 response unit 17 relay unit 100 base station 101 communication unit 102 storage unit 103 ionosphere map DB
104 Reception information DB
105 sea information map 110 control unit 111 message transmission / reception unit 112 error detection unit 113 relay identification unit 114 relay instruction unit 115 update unit

Claims (12)

Obtain an ionosphere map that shows the radio field intensity between each location during radio communication using the ionosphere at sea.
Identify the first ship that succeeded in wireless communication and the second ship that failed in wireless communication,
Based on the ionosphere map, identify a third ship that can communicate with the second ship from the first ship,
An information transmission program for causing a computer to execute a process of relaying a radio signal to the second ship to the identified third ship. Obtain an ionosphere map that shows the radio field intensity between each location during radio communication using the ionosphere at sea.
Identify a first ship that has received a response signal to a radio signal transmitted to each ship, and a second ship that cannot receive the response signal,
Based on the ionosphere map, identify a third ship that can communicate with the second ship from the first ship,
An information transmission program for causing a computer to execute a process of relaying a radio signal to the second ship to the identified third ship. Obtain an ionosphere map that shows the radio field intensity between each location during radio communication using the ionosphere at sea.
Identify the first ship that succeeded in wireless communication and the second ship that failed in wireless communication,
The position information of the two second ships with different times received from the wireless devices provided in the second ship, or the latest position information and the latest previous position information of the second ship Estimating the position of the second vessel based on the direction of movement specified on the basis of ,
From the first ship, based on the estimated position of the second ship and the ionosphere map, identify a third ship that can communicate with the second ship,
An information transmission program for causing a computer to execute a process of relaying a radio signal to the second ship to the identified third ship. Further causing the computer to execute a process of periodically acquiring and holding position information of each ship that performs wireless communication on the sea ,
According to the ionosphere map, the process of identifying the third ship is performed such that the radio field intensity with the latest position of the second ship to be held is the latest position of each of the plurality of first ships. The information transmission program according to claim 1 or 2, wherein the strongest position is specified, and the ship at the specified position is specified as the third ship. Further causing the computer to execute a process of periodically acquiring and holding position information of each ship that performs wireless communication on the sea ,
The estimation process specifies the speed of the second ship based on the latest position information and the latest previous position information of the second ship held, and the speed of the second ship The information transmission program according to claim 3 , wherein the current position of the second ship is estimated from the latest position information of the second ship . Obtain an ionosphere map that shows the radio field intensity between each location during radio communication using the ionosphere at sea.
Identify the first ship that succeeded in wireless communication and the second ship that failed in wireless communication,
Based on the ionosphere map, identify a third ship that can communicate with the second ship from the first ship,
An information transmission method in which a computer executes a process of relaying and transmitting a radio signal to the second ship to the identified third ship. Obtain an ionosphere map that shows the radio field intensity between each location during radio communication using the ionosphere at sea.
Identify a first ship that has received a response signal to a radio signal transmitted to each ship, and a second ship that cannot receive the response signal,
Based on the ionosphere map, identify a third ship that can communicate with the second ship from the first ship,
An information transmission method in which a computer executes a process of relaying and transmitting a radio signal to the second ship to the identified third ship. Obtain an ionosphere map that shows the radio field intensity between each location during radio communication using the ionosphere at sea.
Identify the first ship that succeeded in wireless communication and the second ship that failed in wireless communication,
The position information of the two second ships with different times received from the wireless devices provided in the second ship, or the latest position information and the latest previous position information of the second ship Estimating the position of the second vessel based on the direction of movement specified on the basis of ,
From the first ship, based on the estimated position of the second ship and the ionosphere map, identify a third ship that can communicate with the second ship,
An information transmission method in which a computer executes a process of relaying and transmitting a radio signal to the second ship to the identified third ship. An acquisition unit for acquiring an ionosphere map indicating the radio field intensity between each position during radio communication using the ionosphere at sea;
A identifying unit that identifies a first ship that has succeeded in wireless communication and a second ship that has failed in wireless communication;
Based on the ionosphere map, the second ship with respect to the third ship specified as the specifying unit for specifying the third ship that can communicate with the second ship from the first ship. An information transmission device comprising: an execution unit that relays and transmits a radio signal to An acquisition unit for acquiring an ionosphere map indicating the radio field intensity between each position during radio communication using the ionosphere at sea;
A identifying unit that identifies a first ship that has received a response signal to a radio signal transmitted to each ship, and a second ship that cannot receive the response signal;
Based on the ionosphere map, a specifying unit that specifies a third ship that can communicate with the second ship from the first ship,
An information transmitting apparatus comprising: an execution unit that relays and transmits a radio signal to the second ship to the identified third ship. An acquisition unit for acquiring an ionosphere map indicating the radio field intensity between each position during radio communication using the ionosphere at sea;
A identifying unit that identifies a first ship that has succeeded in wireless communication and a second ship that has failed in wireless communication;
The position information of the two second ships with different times received from the wireless devices provided in the second ship, or the latest position information and the latest previous position information of the second ship An estimation unit for estimating a position of the second ship based on a moving direction specified based on the movement direction;
From the first ship, based on the estimated position of the second ship and the ionosphere map, a specifying unit that specifies a third ship that can communicate with the second ship,
An information transmitting apparatus comprising: an execution unit that relays and transmits a radio signal to the second ship to the identified third ship. Obtain an ionosphere map that shows the radio field intensity between each position in wireless communication using the ionosphere in areas where communication is difficult,
Identifying a first device with successful wireless communication and a second device with failed wireless communication;
Based on the ionosphere map, identify a third device that can communicate with the second device from the first device,
An information transmission program for causing a computer to execute processing for relaying and transmitting a radio signal to the second device to the identified third device.

Images