JP7776301B2 - How to display other ships using international VHF communications - Google Patents

Description

While it is possible to determine where other ships are located on the ocean by looking at the display on an ECDIS (Electronic Chart Display and Information System), it is difficult to determine which ship on the ECDIS is communicating with via international VHF communications, etc. The present invention aims to solve this problem in order to contribute to safe navigation.

In recent years, autonomous driving has made great strides, and practical application is fast approaching. Similarly, research into autonomous ship navigation has been active, and it is said that practical application is also near. However, while there are buoys that indicate routes in limited areas such as congested waters, safe navigation on the ocean largely relies on individual communication between ships to confirm coordinates and direction of travel.

AIS (Automatic Identification System) is widely used at sea for safety reasons, and the coordinates of other ships that become clear when receiving AIS signals are displayed on ECDIS, allowing ships to understand the situation around their own ship. The information displayed includes heading, heading, and destination, but because AIS information alone does not tell when to change course, individual voice communication is often used to confirm safety as a precaution.

Furthermore, the low adoption rate of AIS among small fishing boats, for which there is no requirement to install AIS, is also an issue. Many owners of these small fishing boats are hesitant to notify fishing cooperatives of their fishing situation, and the adoption rate is very low. To improve safety in these cases, there is active research into methods for determining the location of vessels without AIS. One method, for example, is to use multiple directional antennas to locate the location of communication signals from vessels without AIS.

In addition, in recent years, there has been a report of a method that takes advantage of the fact that there is a certain relationship between the amount of noise components in international VHF communications and the distance between communications, and estimates the distance between parties in international VHF communications by analyzing the noise components.

This invention assumes that surrounding ships are equipped with AIS, and relates to a means of enhancing safety by combining ship information obtained from voice calls with position information obtained from the AIS. In addition, when a ship without AIS is discovered, it is possible to notify the crew by issuing a warning or other means.

Patent Publication No. 2017-163300

When multiple ships are sailing at sea aiming for safe navigation, the first step to ensure safety is to know the positions of the other ships displayed on the ECDIS. However, just because another ship is sailing nearby does not mean that they will always avoid it; in congested waters, the reality is that ships often approach each other after mutual understanding through individual communications, etc., and in such cases it is difficult to judge safety simply based on information obtained from the screen.

Navigation based on mutual understanding as described above involves constantly exchanging information such as navigation direction and mutual positional awareness via international VHF communications. Therefore, if the information about other ships plotted on the ECDIS could also indicate whether the ship is communicating with international VHF communications, the information could be used more effectively.

To achieve this, it would be possible to perform voice recognition on the voice data of international VHF communications and link this to AIS information using the position and ship names contained in the voice stream, but currently the information contained in the voice stream and the AIS information are treated separately.

Thus, the present invention aims to make it possible to know whether an approaching ship displayed on ECDIS is the party with whom communication is being conducted by performing voice recognition on the voice signals contained in the communication, identifying the ship name contained in the voice and linking it to AIS information to add information to ECDIS, and to prevent a decrease in voice recognition rate even in high-noise international VHF communications at sea.

This device realizes safe navigation using ship-to-ship communications via international VHF radio.
The ship name information obtained by recognizing the voice information in the international VHF communication by the learning voice recognition unit is designated as ship name information 1,
The ship name information included in the AIS information transmitted by the AIS devices of multiple ships received by the ship is defined as a ship name information group,
When the result of searching the ship name information group for the ship name information that is equal to or smaller than a predetermined threshold and has the smallest error with the ship name information 1 is set as ship name information 2,
The system is characterized by having a ship name extraction unit that links the ship name information 2 with the ship name information 1.
The method of displaying other ships will be based on international VHF communications.

an electronic chart information display unit that displays ship information obtained from AIS information;
an information superimposing unit that superimposes the linking result of the ship name extraction unit on the electronic chart information display unit;
A method for displaying other ships using international VHF communications, characterized by the following:

The learning-type speech recognition unit
a learning data setting unit that sets the ship name voice signal in the international VHF communication as learning data;
a teacher data setting unit that sets, as teacher data, a character string that has the smallest difference from the learning data from among the ship name information included in the AIS information;
The method for displaying other ships using international VHF communications is characterized by comprising:

The learning-type speech recognition unit
a voice storage unit for storing feature data of input voice;
a stored voice determination unit that determines whether the currently input voice is feature data already stored in the voice storage unit;
The method for displaying other ships using international VHF communications is characterized by comprising:

The learning-type speech recognition unit
When a difference between the learning data set by the learning data setting unit and the teacher data set by the teacher data setting unit is equal to or greater than a predetermined threshold,
The input vessel name voice signal is determined to be a vessel name not displayed on the electronic chart information display unit,
The electronic chart information display unit is characterized by displaying a warning that the ship is not equipped with AIS.
The method of displaying other ships will be based on international VHF communications.

According to claim 1 of the present invention, voice recognition makes it possible to extract ship name information and identification numbers from the voice string of the other party in international VHF communications and link them to AIS information.

According to claim 2 of the present invention, it is possible to superimpose additional information about other vessels on a display device that displays nearby vessels, such as ECDIS. Note that superimposing additional information also includes displaying information obtained through voice recognition, or simply highlighting the information.

According to claim 3 of the present invention, even in adverse environments such as those where weather conditions increase noise in international VHF communications, it is possible to perform highly accurate voice recognition of voice sequences by training a voice recognition device using AIS information as training data.

According to claim 4 of the present invention, by storing voice characteristic information, when communicating again with a party with whom you have previously communicated, it is possible to superimpose the additional information of the other vessel displayed on the display without performing voice recognition.

According to claim 5 of the present invention, if the other ship communicating with the international VHF radio is not equipped with AIS, it is possible to detect this and issue a warning that the information may not be displayed on the electronic chart information display unit.

Examples of embodiments of the present invention Overall processing flow Speech recognition training data acquisition process flow Audio data saving process flow Processing flow for communication with non-AIS equipped ships

Embodiments of the present invention will be described in detail below with reference to the drawings.

Figure 1 shows information exchange using the AIS (Automatic Identification System), where 101 is the other vessel, 103 is the vessel itself, 105 is a facility installed on land such as a maritime traffic center, and 107 is the ECDIS (Electronic Chart Display and Information System).

AIS is a device that allows ships navigating the ocean to exchange navigation information with each other, and is now mandatory for ships designated by the SOLAS Convention to be equipped with it in order to prevent collisions and ensure the safety of human life. However, the current installation rate is still low on small fishing boats and other vessels. Therefore, when considering maritime safety, it is necessary not only to assume that AIS is installed, but also to consider a system that takes into account ships that do not have it.

As shown in Figure 1, AIS consists of equipment installed on land and devices installed on ships. Individual data such as the ship's identification code, name, position, course, speed, and destination is automatically transmitted via VHF radio waves from the AIS device installed on ship 101, and is received by receivers on other ships 103 sailing nearby, or by receiving equipment 105 installed at a maritime traffic center on land. The received information is visually communicated to passengers, for example, by ECDIS 107.

AIS-dedicated frequencies are allocated from the VHF maritime mobile service frequencies, and the communication range is basically equivalent to the line-of-sight range from the antenna, which is approximately 37 to 56 km.

Figure 2 shows the overall processing flow for the present invention. The receiver 201 receives international VHF communications from other ships. In international VHF communications, it is common to first call the other ship on a contact setup channel, and then switch to a call channel to make the call. For convenience, the receiver 201 is shown after switching to the call channel.

When the receiver 201 receives an international VHF communication from the other vessel, the voice signal is subjected to voice recognition by the voice recognition unit 203. The vocabulary recognized and extracted by this unit 203 is the ship's name. As will be described later, extraction methods include searching for the ship's name contained in the AIS received information from a voice string, or by recognizing words that indicate a ship's name, such as "~maru" or "~go." In this way, the name of the other vessel can be obtained from the communication voice using voice recognition.

Next, the display control unit 205 compares the acquired ship name with a list of ship names of surrounding ships obtained from AIS signals at any time, and searches for ships that match the ship name from the list. For ships with matching ship names, the display control unit 205 turns on a highlight flag for those ships.

The display unit 207 displays multiple ships sailing around the ship using the AIS device, and by emphasizing the color and brightness of ships with the highlight flag turned on, ships with the highlight flag turned on can be visually identified.

In this way, this invention makes it possible to display the symbol of the other vessel with which you are communicating via international VHF communications in a format that allows you to visually identify which symbol among the symbols of other vessels scattered across the ECDIS is the other vessel. This makes it possible to instantly and visually understand the relative position of the other vessel with which you are communicating.

Figure 3 shows the process flow for improving the recognition rate of a voice recognition device. The process of changing various parameters of a voice recognition device to improve the recognition rate is also called training.

As mentioned above, ships equipped with AIS automatically transmit AIS information as appropriate. This AIS information includes the ship's identification code, name, position, course, destination, etc.

AIS information from surrounding ships is received by the AIS receiver 301, and the AIS information acquisition unit 303 identifies each piece of AIS information. In this invention, ship name information is used from the AIS information. Meanwhile, crew members of both ships can exchange voice communications via international VHF communication. As shown in Figure 3, the international VHF receiver 305 receives signals from the other ship, and the voice recognition unit 307 recognizes the contents of the voice communication. In this invention, the name of the other ship is recognized.

When training the voice recognition unit 307 in this invention, the information obtained from the AIS information acquisition unit 303 is used as training data to adjust the voice recognition unit 307. Here, as an example, we will take up the case of learning ship names.

The AIS information acquisition unit 303 acquires the character strings of the names of surrounding ships and creates a ship name database consisting of the number of surrounding ships. Meanwhile, the voice recognition unit 307 acquires the voice signals of other ships communicating via international VHF communications, performs voice recognition on these signals, and converts them into character strings. However, since it is common for ships to state their names in voice signals at sea, the voices can be considered to contain the ship's name.

Therefore, by performing voice recognition on the voice signals of international VHF communications and linking them to a ship name selected from a ship name database made up of the AIS information, information can be added to the ECDIS, and various methods for this selection can be considered.

For example, each ship name database 309 is searched for the character string of the voice recognition result, and the ship name string with the smallest difference is used as the recognition result and linked to the corresponding AIS information.

As another method, since the ship name voice continues with phrases indicating the ship's name, such as "~maru" or "~go", the voice recognition unit 307 extracts these standard words from the voice string, then extracts the ship's name, converts it into a string, and then compares the ship's name string with the strings in the ship's name database, and the ship's name string with the smallest difference in the ship's name database is used as the recognition result, which is then linked to the corresponding AIS information.

Any of the methods described above can be used to link the voice recognition results with the AIS information, but by linking them in this way, the results can be used to improve the voice recognition rate. In other words, the voice recognition results linked with the AIS information are used as training data, and this is learned so that the recognition result by the voice recognition unit 307 becomes the above-mentioned character string, improving the recognition rate. In other words, as described above, the voice recognition result and the ship name database 309 do not perfectly match, and the result with the least error is used, but by repeating this process, the error will become smaller from the next process onwards.

The parameters used by the speech recognition unit 307 may simply be speech waveforms, but may also be any other parameters such as linear prediction coefficients (LPC coefficients), partial autocorrelation coefficients (PARCOR coefficients), or speech features (cepstrum coefficients), and are not limited to these in the present invention.

Furthermore, when comparing the voice recognition results with the ship name database, it is possible to simply compare the waveforms corresponding to the characters or the shapes of the speech formants. For example, it is possible to determine that there is little difference between "ta" and "cha" based on the plosive sounds and vowels that are close to sine waves obtained from the character information. However, the present invention does not limit the means of comparing such errors to this.

In addition, various methods can be considered for speech recognition, such as neural network methods, which use a method called backpropagation to modify the coefficients of a group of filters so that training data is output when training data is input to the group of filters, deep learning methods, which have seen remarkable development in recent years, and fuzzy inference methods, but these are not intended to be limiting within the scope of the present invention.

In this way, in the present invention, the voice recognition unit 307 performs voice recognition on the ship name to obtain a string of ship name characters, and the ship name with the smallest error compared to the voice recognition result is extracted from the ship name database created by the AIS information acquisition unit 303. This is then used as training data to train the voice recognition unit 307, making it possible to maintain high voice recognition accuracy even when there is increased noise due to factors such as weather around the ship, making misrecognition more likely to occur.

Figure 4 shows the flow for saving the parameters calculated above to enable the speech recognition unit 403 to recognize the international VHF speech signal received by the receiver 401. In other words, the speech waveform itself, as well as the linear prediction coefficients and partial autocorrelation coefficients generated during the speech recognition process, are saved in the storage device 405. The saved speech recognition results are also saved in association with the ship name.

When the voice parameters of the other vessel with which communication has been previously made are stored in the storage device 405 and a currently received voice signal is input to the voice recognition unit 403, the voice recognition unit first converts the voice signal into a parameter string for voice recognition as described above.

The parameter sequence is then compared with the parameter sequence stored in the memory device 405. If a parameter sequence with a difference amount below the error threshold set as the initial value is found in the memory device 405, the ship name of the voice recognition result stored in association with the found parameter sequence is used as the voice recognition result.

This process means that when communicating again with a ship with which communication has been previously conducted, if similar parameters exist in the storage device 405, it is possible to obtain the name of the other ship without having to perform subsequent recognition processing to calculate the voice parameters.

Here, if the difference is less than the error threshold, the present invention does not limit whether to perform voice recognition processing again to update the data stored in the storage device 405, or to output the voice recognition results without performing voice recognition processing.

Figure 5 is a flow chart explaining the case where the communication partner does not have an AIS device. As described above, when comparing the voice recognition result with the ship name database 513 consisting of AIS information obtained from the AIS receiver 511, if no matching ship name is found within a predetermined error threshold, it can be determined that the communication partner does not have an AIS. The AIS presence/absence determination unit 501 stores the predetermined error threshold and calculates whether all errors between the voice recognition result and the ship name database 513 are above the error threshold.

In this case, the display control unit 507 transmits a string of characters indicating that the communication partner is not equipped with AIS to the display unit 509, and the string of characters is displayed on the display unit 509. Note that the string of characters can be displayed in any area on the display, by flashing a warning lamp, or by opening a separate window, but this is not a limitation of the present invention. Furthermore, the displayed content is not limited to stating that the communication partner is not equipped with AIS; it is also possible to display a string of characters that is the result of voice recognition, and is not a limitation of the present invention.

As described above, according to the present invention, when international VHF communications are conducted between ships, the name of the ship included in the communication partner can be recognized by voice, and the user can be informed of the other ship on a display device such as ECDIS.If the communication partner is a ship that does not have AIS and is not displayed on the display device, a warning can be displayed.This improves the problem that, in the past, it was not possible to instantly determine which of the surrounding ships displayed on the display device was the communication partner, and ultimately contributes to safe navigation.

101...communication partner ship, 103...own ship,
105...Ground station, 107...ECDIS,
201...receiving unit, 203...speech recognition unit,
205...display control unit, 207...display unit,
301...AIS receiving unit, 303...AIS information acquiring unit,
305...International VHF receiving unit, 307...Voice recognition unit,
309...Ship name database,
401: Receiving unit; 403: Speech recognition unit;
405...Storage device,
501...AIS presence/absence determination unit, 503...International VHF receiving unit,
505...speech recognition unit, 507...display control unit,
509...display unit, 511...AIS receiving unit,
513...Ship name database

Claims (5)

This device realizes safe navigation using ship-to-ship communications via international VHF radio.
The ship name information obtained by recognizing the voice information in the international VHF communication by the learning voice recognition unit is designated as ship name information 1,
The ship name information included in the AIS information transmitted by the AIS devices of multiple ships received by the ship is defined as a ship name information group,
When the result of searching the ship name information group for the ship name information that is equal to or smaller than a predetermined threshold and has the smallest error with the ship name information 1 is set as ship name information 2,
The system is characterized by having a ship name extraction unit that links the ship name information 2 with the ship name information 1.
How to display other ships using international VHF communications an electronic chart information display unit that displays ship information obtained from AIS information;
an information superimposing unit that superimposes the linking result of the ship name extraction unit on the electronic chart information display unit;
2. The method for displaying other ships using international VHF communications according to claim 1, comprising: The learning-type speech recognition unit
a learning data setting unit that sets the ship name voice signal in the international VHF communication as learning data;
a teacher data setting unit that sets, as teacher data, a character string that has the smallest difference from the learning data from among the ship name information included in the AIS information;
3. The method for displaying other ships using international VHF communications according to claim 1 or 2, comprising: The learning-type speech recognition unit
a voice storage unit for storing feature data of input voice;
a stored voice determination unit that determines whether the currently input voice is feature data already stored in the voice storage unit;
The method for displaying other ships using international VHF communications according to any one of claims 1 to 3, characterized in that: The method for displaying other ships using international VHF communication according to claims 2 and 3,
The learning-type voice recognition unit determines that the input ship name voice signal is a ship name not displayed on the electronic chart information display unit when a difference between the learning data set by the learning data setting unit and the teacher data set by the teacher data setting unit is equal to or greater than a predetermined threshold, and warns the electronic chart information display unit that the ship is not equipped with AIS.