CN119126079A - A side-scan sonar communication system - Google Patents

Abstract

The invention relates to a side-scan sonar communication system, which is applied to the technical field of sonar communication, and comprises: for a control instruction sent by an integrated control terminal, an SDK module receives, analyzes and sends the control instruction to an underwater processing terminal through an instruction communication link, the underwater processing terminal also receives the analyzed command sent by the SDK module through the instruction communication link, and sends it to a hardware terminal after secondary analysis, the sonar data collected by the hardware terminal is pre-processed through a data communication link and then sent to the data communication link of the SDK module, and the data communication link of the SDK module processes the pre-processed data to obtain sonar image data and sends it to the integrated control terminal; the application adopts the instruction communication link to realize the transmission of the control instruction and the data communication link to realize the transmission of the data respectively; and avoids the problem of low communication efficiency caused by using one communication link to simultaneously send and receive data and commands in the prior art.

Description

Side-scan sonar communication system

Technical Field

The invention relates to the technical field of sonar communication, in particular to a side-scan sonar communication system.

Background

The side-scan sonar is an important component of a product and is used for realizing the function of quickly searching a small side target under the condition of high navigational speed and is quite important for offshore navigation, and for sonar equipment, the working flow is that a control instruction of an upper computer is received, a sonar signal is sent according to the control instruction, and image data acquired by the sonar signal is returned to the upper computer;

In the prior art, a communication link is generally used to implement the transmission of a control command and the return of image data, and the simultaneous transmission of the command and the data on the same link results in resource contention, so that the command and the data interfere with each other during the transmission process, thereby reducing the overall communication efficiency, and in addition, the command generally has a higher priority, however, the transmission on the same link will cause the delay increase of the command, which affects the response speed of the system, because the command usually needs to respond quickly, while the data transmission will occupy a lot of time, which causes the delay of the command processing, and the transmission and reception of the command and data will be affected after the communication link fails, so the stability of the system is low.

Disclosure of Invention

Therefore, the present invention aims to provide a side scan sonar communication system, so as to solve the problems in the prior art that a communication link is adopted to implement transmission of a control command and return of image data, so that the command and the data interfere with each other in a transmission process, thereby reducing overall communication efficiency, and the data transmission occupies a lot of time, which results in delay of command processing, and the transmission and the reception of the command and the data are affected after the communication link fails, and the stability of the system is low.

According to a first aspect of an embodiment of the present invention, there is provided a side-scan sonar communication system, the system comprising:

The integrated control terminal is used for sending a control instruction to the SDK module, receiving sonar image data returned by the SDK module and displaying the sonar image data;

the SDK module is used for receiving a control instruction sent by the integrated control terminal through an instruction communication link, translating and analyzing the control instruction to obtain a sonar working parameter, packaging the sonar working parameter group into a sonar working command, and sending the sonar working command to an underwater processing end;

The system is also used for receiving the preprocessing data sent by the underwater processing end through a data communication link, carrying out image processing on the preprocessing data to obtain sonar image data, and sending the sonar image data to the comprehensive control terminal;

The underwater processing end is used for receiving a sonar working command sent by the SDK module through an instruction communication link, and obtaining a sonar transmitter driving instruction and a sonar receiver driving instruction after internal translation analysis is carried out on the sonar working command;

The system is also used for converting the echo signals into digital signals through a data communication link, performing orthogonal transformation and digital filtering processing on the digital signals to obtain preprocessing data, and sending the preprocessing data to the SDK module.

Preferably, the method comprises the steps of,

The SDK module comprises a first control command analysis module, a first communication module, a signal processing module and a protocol packaging output module;

The first control command analysis module is used for receiving a control command transmitted by the integrated control terminal in a SOCKET form, translating and analyzing the control command to obtain a sonar working parameter, packaging the sonar working parameter set into a sonar working command, and sending the sonar working command to the first communication module;

the first communication module is used for receiving the sonar operating command sent by the control command analysis module and sending the sonar operating command to the underwater processing end, and is also used for receiving the preprocessing data sent by the underwater processing end and sending the preprocessing data to the signal processing module;

the signal processing module is used for receiving the preprocessing data sent by the first communication module, and carrying out compression, denoising, beam forming and image correction processing on the preprocessing data to obtain the sonar image data;

and the protocol packaging output module is used for receiving the sonar image data sent by the signal processing module and sending the sonar image data to the comprehensive control terminal.

Preferably, the method comprises the steps of,

The underwater processing end comprises a second communication module, a second control command analysis module, a hardware control module, a signal acquisition module, a signal preprocessing module and a data packaging module;

The second communication module is used for receiving the sonar operating command sent by the first communication module and sending the sonar operating command to the second control command analysis module, and is also used for receiving the preprocessing data sent by the data packaging module and sending the preprocessing data to the first communication module;

The second control command analysis module is used for receiving the sonar operating command sent by the second communication module, carrying out internal translation analysis on the sonar operating command to obtain a sonar transmitter driving command and a sonar receiver driving command, and sending the sonar transmitter driving command and the sonar receiver driving command to the hardware control module;

the hardware control module is used for receiving the sonar transmitter driving instruction and the sonar receiver driving instruction sent by the second control command analysis module, and controlling the sonar transmitter to transmit a sonar signal according to the sonar transmitter driving instruction;

the signal acquisition module is used for acquiring echo signals of the sonar receiver, converting the echo signals into digital signals and then sending the digital signals to the signal preprocessing module;

the signal preprocessing module is used for performing orthogonal transformation and digital filtering processing on the received digital signals to obtain preprocessed data, and sending the preprocessed data to the data packaging module;

The data packaging module is used for packaging the received preprocessed data into single-frame data and sending the single-frame data to the second communication module in a blocking mode.

Preferably, the method comprises the steps of,

After receiving the control instruction transmitted by the integrated control terminal in the form of SOCKET, the first control command analysis module performs definition domain inspection on the control instruction, and if the control instruction does not accord with the corresponding definition domain, error reporting processing is performed.

Preferably, the method comprises the steps of,

And the first control command analysis module receives the control command transmitted by the integrated control terminal in the form of SOCKET, performs definition domain inspection, aligns the control command through a command head and performs command length judgment operation if the control command accords with the corresponding definition domain, and does not perform subsequent translation analysis operation if the command length of the control command does not accord with a preset command length standard.

Preferably, the method further comprises:

A temperature sensor is arranged in the sonar transmitter, the internal temperature of the sonar transmitter is detected through the temperature sensor, and temperature data are sent to the hardware control module;

the hardware control module is also used for comparing the temperature data with a preset temperature threshold after receiving the temperature data, and sending a power supply driving instruction to a transmitting power supply of the sonar transmitter to control the transmitting power supply to be closed if the temperature data is larger than or equal to the preset temperature threshold;

And the hardware control module is also used for sending a power driving instruction to the transmitting power supply of the sonar transmitter again after the transmitting power supply is turned off and controlling the transmitting power supply to be turned on when the received temperature data is lower than a preset temperature threshold value.

Preferably, the method comprises the steps of,

When the sonar transmitter transmits a sonar signal, an array transmission channel is utilized to transmit a multichannel sonar signal;

when the sonar receiver receives the echo signals, the array receiving channel is utilized to receive the echo signals returned after the multichannel sonar signals meet the target.

Preferably, the method comprises the steps of,

The first control command analysis module and the protocol packaging output module are respectively connected with the integrated control terminal by SOCKET;

And the first communication module and the second communication module are used for receiving and transmitting data or commands by establishing a TCP/IP communication link.

The technical scheme provided by the embodiment of the invention can comprise the following beneficial effects:

The application receives, analyzes and transmits the control command sent by the integrated control terminal to the underwater processing terminal through the command communication link, the underwater processing terminal receives the analyzed command sent by the SDK module through the command communication link, carries out secondary analysis and then sends the command to the hardware terminal, carries out preprocessing on sonar data acquired by the hardware terminal through the data communication link and then sends the data to the data communication link of the SDK module, and the data communication link of the SDK module processes the preprocessed data to obtain sonar image data and sends the sonar image data to the integrated control terminal.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.

FIG. 1 is an overall system schematic diagram of a side-scan sonar communication system, shown in accordance with an example embodiment;

FIG. 2 is a system diagram of an SDK module shown according to another exemplary embodiment;

FIG. 3 is a system schematic diagram of an underwater processing end shown according to another exemplary embodiment;

FIG. 4 is a system diagram illustrating an instruction communication link of an SDK module according to another example embodiment;

FIG. 5 is a system diagram illustrating a data communication link of an SDK module according to another exemplary embodiment;

FIG. 6 is a system diagram illustrating an instruction communication link of an underwater processing end according to another exemplary embodiment;

FIG. 7 is a system diagram illustrating a data communication link of an underwater processing end according to another exemplary embodiment;

FIG. 8 is a system diagram illustrating a communication connection of an SDK module with an underwater processing side according to another exemplary embodiment;

in the drawing, a 1-comprehensive control terminal, a 2-SDK module, a 3-underwater processing end, a 201-first control command analysis module, a 202-first communication module, a 203-signal processing module, a 204-protocol packaging output module, a 301-second communication module, a 302-second control command analysis module, a 303-hardware control module, a 304-signal acquisition module, a 305-signal preprocessing module and a 306-data packaging module are arranged.

Detailed Description

Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numbers in different drawings refer to the same or similar elements, unless otherwise indicated. The implementations described in the following exemplary examples do not represent all implementations consistent with the invention. Rather, they are merely examples of apparatus and methods consistent with aspects of the invention as detailed in the accompanying claims.

Example 1

FIG. 1 is an overall system schematic diagram of a side-scan sonar communication system, as shown in FIG. 1, according to an example embodiment, the system comprising:

the integrated control terminal 1 is used for sending a control instruction to the SDK module 2, receiving sonar image data returned by the SDK module 2 and displaying the sonar image data;

The SDK module 2 is used for receiving a control instruction sent by the integrated control terminal 1 through an instruction communication link, translating and analyzing the control instruction to obtain a sonar working parameter, packaging the sonar working parameter set into a sonar working command, and sending the sonar working command to the underwater processing terminal 3;

The system is also used for receiving the preprocessing data sent by the underwater processing end 3 through a data communication link, carrying out image processing on the preprocessing data to obtain sonar image data, and sending the sonar image data to the comprehensive control terminal 1;

The underwater processing end 3 is used for receiving a sonar working command sent by the SDK module 2 through an instruction communication link, carrying out internal translation analysis on the sonar working command to obtain a sonar transmitter driving instruction and a sonar receiver driving instruction, controlling the sonar transmitter to transmit a sonar signal according to the sonar transmitter driving instruction, and controlling the sonar receiver to receive an echo signal returned after the sonar signal meets a target according to the sonar receiver driving instruction;

The system is also used for converting the echo signal into a digital signal through a data communication link, performing orthogonal transformation and digital filtering processing on the digital signal to obtain preprocessing data, and transmitting the preprocessing data to the SDK module 2;

It can be understood that, in this embodiment, for the control instruction sent by the integrated control terminal 1, the SDK module 2 receives, parses and sends the control instruction to the underwater processing terminal 3 through the instruction communication link, the underwater processing terminal 3 receives, and sends the parsed command sent by the SDK module 2 to the hardware terminal after performing secondary parsing, the sonar data collected by the hardware terminal is preprocessed through the data communication link and then sent to the data communication link of the SDK module 2, and the data communication link of the SDK module 2 processes the preprocessed data to obtain the sonar image data and then sends the sonar image data to the integrated control terminal 1.

It will be understood that, as shown in fig. 2, the SDK module 2 includes a first control command parsing module 201, a first communication module 202, a signal processing module 203, and a protocol packaging output module 204;

the first control command analysis module 201 and the first communication module 202 form an instruction communication link of the SDK module 2, the first control command analysis module 201 establishes a socketconnection with the integrated control terminal 1, the integrated control terminal 1 sends a control instruction to the first control command analysis module 201, the first control command analysis module 201 receives the control instruction sent by the integrated control terminal 1 in a socketform, and then translates and analyzes the control instruction to obtain a sonar operating parameter, and meanwhile, the sonar operating parameter group is packaged into a sonar operating command, the packaged sonar operating command is sent to the first communication module 202, and the first communication module 202 sends the sonar operating command to the instruction communication link of the underwater processing end 3;

The first communication module 202 receives the pre-processed data sent by the data communication link of the underwater processing end 3 and sends the pre-processed data to the signal processing module 203, the signal processing module 203 compresses, denoises, forms a beam and corrects the image to obtain sonar image data, sends the sonar image data to the protocol packaging output module 204, the protocol packaging output module 204 establishes SOCKET connection with the comprehensive control terminal 1, the protocol packaging output module 204 packages the processed sonar image data into a user data packet according to a user data protocol, and the user data packet is transmitted to the comprehensive control terminal 1, and the comprehensive control terminal 1 further processes the received image data and directly displays the user data on a screen;

it can be understood that, as shown in fig. 3, the underwater processing end 3 includes a second communication module 301, a second control command analysis module 302, a hardware control module 303, a signal acquisition module 304, a signal preprocessing module 305, and a data packaging module 306;

As shown in fig. 8, the connection between the SDK module 2 and the underwater processing end 3 is implemented through a first communication module 202 and a second communication module 301, and the first communication module 202 and the second communication module 301 perform data or command receiving and sending by establishing a TCP/IP communication link;

As shown in fig. 6, the second communication module 301, the second control command analysis module 302 and the hardware control module 303 form an instruction communication link of the underwater processing end 3, after receiving a sonar operation command sent by the first communication module 202, the second communication module 301 forwards the sonar operation command to the second control command analysis module 302, after receiving the sonar operation command sent by the second communication module 301, the second control command analysis module 302 performs internal translation analysis on the sonar operation command to obtain a sonar transmitter driving instruction and a sonar receiver driving instruction, and meanwhile, sends the sonar transmitter driving instruction and the sonar receiver driving instruction to the hardware control module 303, and after receiving the sonar transmitter driving instruction and the sonar receiver driving instruction, the hardware control module 303 respectively controls the sonar transmitter to transmit a sonar signal and controls the sonar receiver to receive an echo signal;

As shown in fig. 7, the second communication module 301, the signal acquisition module 304, the signal preprocessing module 305 and the data packaging module 306 form a data communication link of the underwater processing end 3, the data acquisition module 304 acquires an echo signal of the sonar receiver, converts the echo signal into a digital signal and sends the digital signal to the signal preprocessing module 305, the signal preprocessing module 305 performs orthogonal transformation and digital filtering processing on the digital signal, and then transmits the digital signal to the data packaging module 306, the data packaging module 306 packages the transmitted data and control parameters jointly into single-frame data, and then transmits the single-frame data to the second communication module 301 in a blocking manner, and then the second communication module 301 returns the single-frame data to the first communication module 202 of the SDK module 2 to realize data return.

It can be understood that in this embodiment, in order to achieve the purposes of transmitting a broad beam once and forming a plurality of parallel beams simultaneously for the beam forming processing of the multichannel received signals, the objective of performing full coverage scanning on the underwater small target under the high navigational speed condition can be achieved.

It can be understood that when the network of the system is abnormally disconnected, the software is automatically reconnected to support the automatic communication recovery after the hardware equipment is reset, and the user data protocol contains sonar working information besides sonar data, so that the working state of the equipment can be conveniently known;

it can be understood that the system adopts the bottom layer driving encapsulation, the receiving and sending command and the data processing are automatically completed in the driving, the user only needs to access the corresponding control command interface and the data interface, the control command and the data receiving adopt independent interfaces and data protocols, the interface protocols are concise, and the user can conveniently use the system;

It can be understood that, the first control command analysis module 201 performs domain checking and control on various input instructions, if the input instructions do not conform to the corresponding domain, the first control command analysis module reports errors and performs corresponding processing, so as to avoid that incorrect data input from the outside affects the normal operation of the system;

it can be understood that, after performing the domain checking, the first control command parsing module 201 does not respond to incorrect data and commands through command header alignment, length judgment and data verification;

It can be understood that, a temperature sensor is arranged in the sonar transmitter, the temperature sensor is in communication connection with the hardware control module 303, the temperature sensor sends the detected real-time temperature in the sonar transmitter to the hardware control module 303, a temperature threshold (generally between 80 ℃ and 90 ℃) is preset in the hardware control module 303, after the hardware control module 3 receives the real-time temperature, the real-time temperature is compared with the preset temperature threshold, if the real-time temperature is greater than or equal to the preset temperature threshold, the temperature in the sonar transmitter is too high, an over-temperature protection mode is required to be entered, the hardware control module 303 transmits an analog/digital circuit power signal, so that the power supply of the sonar transmitter is turned off, and after the temperature is normal, the power supply is restored, and the system can restore to normal operation.

It is to be understood that the same or similar parts in the above embodiments may be referred to each other, and that in some embodiments, the same or similar parts in other embodiments may be referred to.

It should be noted that in the description of the present invention, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Furthermore, in the description of the present invention, unless otherwise indicated, the meaning of "plurality" means at least two.

Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and further implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present invention.

It is to be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above-described embodiments, the various steps or methods may be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, may be implemented using any one or combination of techniques known in the art, discrete logic circuits with logic gates for implementing logic functions on data signals, application specific integrated circuits with appropriate combinational logic gates, programmable Gate Arrays (PGAs), field Programmable Gate Arrays (FPGAs), and the like.

Those of ordinary skill in the art will appreciate that all or a portion of the steps carried out in the method of the above-described embodiments may be implemented by a program to instruct related hardware, where the program may be stored in a computer readable storage medium, and where the program, when executed, includes one or a combination of the steps of the method embodiments.

In addition, each functional unit in the embodiments of the present invention may be integrated in one processing module, or each unit may exist alone physically, or two or more units may be integrated in one module. The integrated modules may be implemented in hardware or in software functional modules. The integrated modules may also be stored in a computer readable storage medium if implemented in the form of software functional modules and sold or used as a stand-alone product.

The above-mentioned storage medium may be a read-only memory, a magnetic disk or an optical disk, or the like.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.

Claims (8)

1. A side-scan sonar communication system, the system comprising:

The integrated control terminal is used for sending a control instruction to the SDK module, receiving sonar image data returned by the SDK module and displaying the sonar image data;

the SDK module is used for receiving a control instruction sent by the integrated control terminal through an instruction communication link, translating and analyzing the control instruction to obtain a sonar working parameter, packaging the sonar working parameter group into a sonar working command, and sending the sonar working command to an underwater processing end;

The system is also used for receiving the preprocessing data sent by the underwater processing end through a data communication link, carrying out image processing on the preprocessing data to obtain sonar image data, and sending the sonar image data to the comprehensive control terminal;

The underwater processing end is used for receiving a sonar working command sent by the SDK module through an instruction communication link, and obtaining a sonar transmitter driving instruction and a sonar receiver driving instruction after internal translation analysis is carried out on the sonar working command;

The system is also used for converting the echo signals into digital signals through a data communication link, performing orthogonal transformation and digital filtering processing on the digital signals to obtain preprocessing data, and sending the preprocessing data to the SDK module.

2. The system of claim 1, wherein the system further comprises a controller configured to control the controller,

The SDK module comprises a first control command analysis module, a first communication module, a signal processing module and a protocol packaging output module;

The first control command analysis module is used for receiving a control command transmitted by the integrated control terminal in a SOCKET form, translating and analyzing the control command to obtain a sonar working parameter, packaging the sonar working parameter set into a sonar working command, and sending the sonar working command to the first communication module;

the first communication module is used for receiving the sonar operating command sent by the control command analysis module and sending the sonar operating command to the underwater processing end, and is also used for receiving the preprocessing data sent by the underwater processing end and sending the preprocessing data to the signal processing module;

the signal processing module is used for receiving the preprocessing data sent by the first communication module, and carrying out compression, denoising, beam forming and image correction processing on the preprocessing data to obtain the sonar image data;

and the protocol packaging output module is used for receiving the sonar image data sent by the signal processing module and sending the sonar image data to the comprehensive control terminal.

3. The system of claim 2, wherein the system further comprises a controller configured to control the controller,

The underwater processing end comprises a second communication module, a second control command analysis module, a hardware control module, a signal acquisition module, a signal preprocessing module and a data packaging module;

The second communication module is used for receiving the sonar operating command sent by the first communication module and sending the sonar operating command to the second control command analysis module, and is also used for receiving the preprocessing data sent by the data packaging module and sending the preprocessing data to the first communication module;

The second control command analysis module is used for receiving the sonar operating command sent by the second communication module, carrying out internal translation analysis on the sonar operating command to obtain a sonar transmitter driving command and a sonar receiver driving command, and sending the sonar transmitter driving command and the sonar receiver driving command to the hardware control module;

the hardware control module is used for receiving the sonar transmitter driving instruction and the sonar receiver driving instruction sent by the second control command analysis module, and controlling the sonar transmitter to transmit a sonar signal according to the sonar transmitter driving instruction;

the signal acquisition module is used for acquiring echo signals of the sonar receiver, converting the echo signals into digital signals and then sending the digital signals to the signal preprocessing module;

the signal preprocessing module is used for performing orthogonal transformation and digital filtering processing on the received digital signals to obtain preprocessed data, and sending the preprocessed data to the data packaging module;

The data packaging module is used for packaging the received preprocessed data into single-frame data and sending the single-frame data to the second communication module in a blocking mode.

4. The system of claim 2, wherein the system further comprises a controller configured to control the controller,

After receiving the control instruction transmitted by the integrated control terminal in the form of SOCKET, the first control command analysis module performs definition domain inspection on the control instruction, and if the control instruction does not accord with the corresponding definition domain, error reporting processing is performed.

5. The system of claim 4, wherein the system further comprises a controller configured to control the controller,

And the first control command analysis module receives the control command transmitted by the integrated control terminal in the form of SOCKET, performs definition domain inspection, aligns the control command through a command head and performs command length judgment operation if the control command accords with the corresponding definition domain, and does not perform subsequent translation analysis operation if the command length of the control command does not accord with a preset command length standard.

6. A system according to claim 3, further comprising:

A temperature sensor is arranged in the sonar transmitter, the internal temperature of the sonar transmitter is detected through the temperature sensor, and temperature data are sent to the hardware control module;

the hardware control module is also used for comparing the temperature data with a preset temperature threshold after receiving the temperature data, and sending a power supply driving instruction to a transmitting power supply of the sonar transmitter to control the transmitting power supply to be closed if the temperature data is larger than or equal to the preset temperature threshold;

And the hardware control module is also used for sending a power driving instruction to the transmitting power supply of the sonar transmitter again after the transmitting power supply is turned off and controlling the transmitting power supply to be turned on when the received temperature data is lower than a preset temperature threshold value.

7. The system of claim 3, wherein the system further comprises a controller configured to control the controller,

When the sonar transmitter transmits a sonar signal, an array transmission channel is utilized to transmit a multichannel sonar signal;

when the sonar receiver receives the echo signals, the array receiving channel is utilized to receive the echo signals returned after the multichannel sonar signals meet the target.

8. The system of claim 3, wherein the system further comprises a controller configured to control the controller,

The first control command analysis module and the protocol packaging output module are respectively connected with the integrated control terminal by SOCKET;

And the first communication module and the second communication module are used for receiving and transmitting data or commands by establishing a TCP/IP communication link.