Beidou-based multi-device fusion remote communication system for unmanned surface vehicle

Abstract

The invention provides a Beidou-based multi-device fusion remote communication system for an unmanned surface vehicle, and the system designs a conventional communication unit and an emergency communication unit, and the conventional communication unit selects a communication link corresponding to a most suitable communication mode in each period through employing a link selection algorithm based on multi-index weighted evaluation. A current application link is switched to the communication link, a data loss prevention strategy is designed in the communication link switching process, so that the communication unit communicates with a control center in emergency and non-emergency states, and the emergency communication unit communicates with the control center through a Beidou short message and communicates with the control center in the emergency state. Therefore, different types of navigation tasks are executed. Therefore, the communication task under the complex environment condition can be undertaken, the most suitable communication link can be quickly selected when the communication link fails, link switching is completed, and remote communication under the emergency state is achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of remote communication of water unmanned surface vehicle, and particularly relates to a Beidou-based multi-device fusion remote communication system for water unmanned surface vehicle. BACKGROUND

[0002] As a new intelligent water operation platform, the water unmanned surface vehicle performs various marine tasks through remote control or autonomous mode, and has significant technical advantages compared with traditional manual operation ships. The unmanned surface vehicle has become an important equipment in the field of modern marine technology due to its compact design, excellent maneuverability and outstanding economy. At present, the unmanned surface vehicle has shown a wide application prospect in many professional fields such as marine surveying, environmental monitoring, marine search and rescue, and marine pollution cleaning.

[0003] The remote communication capability is crucial for the navigation and operation of the unmanned surface vehicle. Through remote control of the unmanned surface vehicle, the manual operation in complex and high-risk waters is effectively replaced, which not only ensures the safety of human life, but also improves the operation efficiency. Therefore, a reliable remote communication mode needs to be established to enable the control center of the shore base or the mother ship to transmit accurate control instructions to the unmanned surface vehicle in real time, and receive the running state parameters and sensing data such as ship position returned by the unmanned surface vehicle. This two-way data interaction constitutes an important technical basis for the practical application of the unmanned surface vehicle.

[0004] At present, the unmanned surface vehicle generally adopts a single system communication architecture, that is, relies on a single communication technology to complete remote communication. This single system architecture has obvious defects: first, various radio remote communication technologies have advantages and disadvantages, and in the environment of more electromagnetic interference on the sea or bad weather conditions, the radio communication performance is prone to be abnormal; second, the single link lacks redundancy, and once the communication mode fails, it will lead to a major accident of the unmanned surface vehicle out of contact. SUMMARY

[0005] In order to solve the above problems in the prior art, the present application provides a Beidou-based multi-device fusion remote communication system for water unmanned surface vehicle. The technical problem to be solved by the present application is solved by the following technical scheme: In a first aspect, a Beidou-based multi-device fusion remote communication system for water unmanned surface vehicle is mounted on the unmanned surface vehicle, and the Beidou-based multi-device fusion remote communication system for water unmanned surface vehicle comprises: The conventional communication unit is configured to select a hardware communication device and a most suitable communication mode corresponding to the hardware communication device from a plurality of hardware communication devices according to a task requirement of the unmanned ship in each period, and switch from a current application link to the most suitable communication mode; and the most suitable communication mode is used to communicate with the control center and receive operation instructions sent by the control center in an emergency state and a non-emergency state and return basic state information of the unmanned ship to the control center. The emergency communication unit is configured to receive control instructions sent by the control center in an emergency state and return basic state information of the unmanned ship to the control center through a self communication mode.

[0006] Optionally, the conventional communication unit is provided with a plurality of hardware communication devices, each of which corresponds to a communication mode, and the communication mode includes a 4G communication mode, a self-organizing network communication mode, a Tianhong communication mode and a Iridium satellite communication mode.

[0007] Optionally, the conventional communication unit is specifically configured to: In each period, a multi-index weighted evaluation link selection algorithm is used to select a most suitable communication mode from the communication modes corresponding to the plurality of hardware communication devices according to a task requirement of the unmanned ship and an economic cost. The current application link is switched to a communication link corresponding to the selected most suitable communication mode.

[0008] Optionally, the multi-index weighted evaluation link selection algorithm used in each period to select the most suitable communication mode from the communication modes corresponding to the plurality of hardware communication devices according to the task requirement of the unmanned ship and the economic cost includes: In each period, a comprehensive score of a communication link corresponding to each communication mode is calculated according to a task type of the unmanned ship and an economic cost. The communication mode corresponding to the communication link with the highest comprehensive score is selected as the most suitable communication mode.

[0009] Optionally, the comprehensive score is calculated according to the following formula:

[0010] In the formula, S represents the comprehensive score of the i-th communication link, B represents a measured value of a current communication bandwidth, T represents a measured value of a current communication time delay, C represents a communication cost of the communication link, and W B and W T represent weights of B and T respectively. i and​​​​​​​​​​ a weight of a communication link performance and a communication cost respectively, .

[0011] Optionally, the switching from the current application link to the communication link corresponding to the most suitable communication mode comprises: determining whether the comprehensive score of the communication link corresponding to the most suitable communication mode exceeds the comprehensive score of the current application link by a hysteresis margin, and if so, triggering the switching; before triggering the switching, storing data to be returned by the unmanned ship locally and pre-connecting and authenticating with the most suitable communication mode to complete the switching preparation; after waiting for the switching preparation to be completed, switching from the current application link to the communication link corresponding to the most suitable communication mode.

[0012] Optionally, in the process of switching from the current application link to the communication link corresponding to the most suitable communication mode, the control center sends the control instruction twice if it detects that the communication link is switching.

[0013] Optionally, the emergency communication unit uses Beidou short message communication as the communication link.

[0014] Optionally, the control instruction comprises an instruction number, and the basic state information comprises a ship position, a ship speed and a heading.

[0015] In a second aspect, the application provides a Beidou-based multi-system fusion remote communication method for a water surface unmanned ship, which is used in a Beidou-based multi-device fusion remote communication system for a water surface unmanned ship, so as to realize the mutual communication between the unmanned ship and the control center in an emergency state and a non-emergency state and execute a task.

[0016] Advantages: The application provides a Beidou-based multi-device fusion remote communication system for a water surface unmanned ship, which designs a conventional communication unit and an emergency communication unit, wherein the conventional communication unit selects a communication link corresponding to the most suitable communication mode in each period by using a link selection algorithm based on multi-index weighted evaluation, and switches from a current application link to the communication link, and a data loss prevention strategy is designed in the communication link switching process, so as to communicate with the control center in an emergency state and a non-emergency state, and the emergency communication unit communicates with the control center through Beidou short message, so as to communicate with the control center in an emergency state and complete the execution of different types of navigation tasks. Therefore, the application can undertake a communication task under complex environmental conditions, and can quickly select the most suitable communication link when the communication link fails, complete the link switching and realize the remote communication in an emergency state.

[0017] The application will be described in further detail below with reference to the drawings and embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a structural schematic diagram of a Beidou-based multi-device fusion remote communication system for a water unmanned surface vehicle provided by the application; Figure 2 is a schematic diagram of selecting the most suitable hardware communication device provided by the application; Figure 3 is a communication schematic diagram of the Beidou-based multi-device fusion remote communication system for a water unmanned surface vehicle provided by the application in an emergency situation; Figure 4 is a schematic diagram of screening a communication link corresponding to the most suitable communication mode provided by the application. DETAILED DESCRIPTION

[0019] The application will be described in further detail below with reference to the drawings and embodiments, but the embodiments of the application are not limited thereto.

[0020] As shown in Figure 1 , the application provides a Beidou-based multi-device fusion remote communication system for a water unmanned surface vehicle, which is carried on the unmanned surface vehicle, and the Beidou-based multi-device fusion remote communication system for the water unmanned surface vehicle comprises: a conventional communication unit, which is used for selecting a carried hardware communication device and a corresponding most suitable communication mode from a plurality of hardware communication devices according to a task demand of the unmanned surface vehicle in each period, and switching from a current application link to the most suitable communication mode; and is used for communicating with a control center by using the most suitable communication mode, and receiving operation instructions sent by the control center in an emergency state and a non-emergency state and returning basic state information of the unmanned surface vehicle to the control center; Referring to Figure 1 , the conventional communication unit carries a plurality of hardware communication devices, each hardware communication device corresponds to a communication mode, and the plurality of communication modes comprise a 4G communication mode, a self-organizing network communication mode, a Tianhong communication mode and a Iridium satellite communication mode.

[0021] Referring to Figure 2 , the selected hardware communication device needs to consider the following four factors: (1) the size and weight of the communication device match the carrying capacity of the unmanned surface vehicle; (2) the reliability of the communication device hardware matches the operating environment of the unmanned surface vehicle; (3) the bandwidth of the communication mode matches the task of the unmanned surface vehicle; and (4) the consideration of redundancy configuration.

[0022] The present application is directed to (1) the matching of the size and weight of the communication equipment with the carrying capacity of the unmanned ship. Considering that the carrying capacity of the unmanned ship is limited, its own size and weight will directly affect the key indicators such as navigation performance and endurance. Therefore, the hardware communication equipment (such as antennas, communication modules, etc.) in the remote communication system needs to match the carrying capacity of the unmanned ship in size and weight, and cannot adversely affect the normal operation of the unmanned ship due to the excessive size and weight of the communication equipment. On the premise of meeting the communication function, small and light equipment should be selected as much as possible.

[0023] The present application is directed to (2) the matching of the reliability of the communication equipment hardware with the operating environment of the unmanned ship. Considering that the unmanned ship usually operates in a complex and variable water environment, it may face wind and waves, electromagnetic interference, salt spray corrosion and other adverse factors, therefore the communication architecture needs to have high reliability. On the one hand, the communication equipment needs to have strong environmental adaptability and be resistant to the influence of harsh environments and not easily damaged. On the other hand, the unmanned ship needs to use mature communication technology to ensure the stability of data transmission and maintain effective communication quality even in complex environments.

[0024] The present application is directed to (3) the matching of the bandwidth of the communication mode with the task of the unmanned ship. Considering the bandwidth of the remote communication of the unmanned ship, it needs to match its task. When the unmanned ship performs tasks such as high-definition image acquisition and real-time video transmission, it needs higher bandwidth to support real-time transmission of a large amount of data. When remotely controlling the unmanned ship to navigate or operate, sufficient bandwidth is also needed to ensure the timeliness of control. If only simple state reporting and instruction receiving tasks are performed, the demand for bandwidth is relatively low. Therefore, the bandwidth needs to be reasonably allocated and dynamically adjusted according to the type of task, both to meet the communication needs of the task and to avoid waste of bandwidth resources.

[0025] The present application is directed to (4) the consideration of redundancy configuration. Redundant design is one of the important foundations to ensure uninterrupted remote communication of the unmanned ship. Redundancy needs to be set in terms of communication mode, equipment, etc. For example, multiple different types of communication modes (such as satellite communication, radio communication, etc.) are deployed at the same time. When a link or device fails, the redundant part can quickly take over the work to avoid communication failure due to single point failure and ensure continuous connection of the unmanned ship with the shore base or other nodes.

[0026] The conventional communication unit of the present application is responsible for providing reliable communication mode for the unmanned ship to perform navigation and operation tasks. At least two communication technologies are carried in the conventional communication unit to ensure redundancy. According to the type of task of the unmanned ship, the communication technology that needs to be carried in the conventional communication unit can be flexibly selected. The conventional communication unit can determine the most suitable communication technology and switch to that link, thereby ensuring the stability of the communication of the unmanned ship.

[0027] For example, unmanned surface vessels (USVs) performing near-shore surveillance missions need to choose communication methods with high bandwidth and low latency, such as 4G and ad hoc network communication. USVs performing offshore hydrological monitoring missions need to choose satellite communication with wide coverage. USVs accompanying their mother ships on offshore scientific research missions can choose a combination of ad hoc network communication and satellite communication.

[0028] The emergency communication unit is used to receive control commands sent by the control center in emergency situations and to return basic status information of the unmanned surface vessel to the control center through its own communication methods.

[0029] The emergency communication unit in this application uses BeiDou short message communication as the communication link. Control commands include command numbers, and basic status information includes ship position, ship speed, and heading.

[0030] Emergency communication requires a communication method with strong anti-interference capabilities to ensure a high success rate. Simultaneously, communication latency should not be excessive to ensure timely control. Therefore, this application selects BeiDou short message communication, which boasts excellent anti-interference performance, as the communication link for the emergency communication unit. In addition to sending emergency operation commands from the control center to the unmanned surface vessel (USV), the emergency communication unit can also be used for the USV to periodically transmit basic status information such as position, speed, and heading back to the control center. This fully utilizes the low cost advantage of BeiDou short message communication, saving data transmission volume on other links. Furthermore, it leverages the strong anti-interference capability of BeiDou short message communication to maintain continuous monitoring of the USV's status. To further ensure the success rate of emergency control, emergency control commands are sent to the USV simultaneously through both the conventional communication unit and the emergency communication unit. Each control command includes a command number; the USV executes a command with the same number only once. The data transmission topology under emergency communication conditions is described in [reference needed]. Figure 3 .

[0031] In one specific embodiment of this application, the conventional communication unit is specifically used for: In each cycle, considering the mission requirements and economic costs of the unmanned surface vessel, a link selection algorithm with multi-index weighted evaluation is used to select the most suitable communication method from various hardware communication devices; and the current application link is switched to the communication link corresponding to the selected most suitable communication method.

[0032] In multi-device integrated remote communication systems, the appropriate selection of communication methods is a core prerequisite for ensuring the efficient and stable execution of missions by unmanned surface vessels (USVs). This can be discussed from two perspectives: mission priority and economic cost. (See [link to relevant documentation]). Figure 4 : 1) Task Priority. The choice of communication method must first ensure the smooth execution of the unmanned surface vessel's (USV) mission. USV missions are diverse, and different missions have significantly different communication requirements, directly determining the initial direction of the communication method selection. When the USV is performing tasks such as real-time acquisition of on-site images and videos, a communication method with sufficient bandwidth should be prioritized. When the USV is performing tasks such as collecting environmental parameters (e.g., water temperature, salinity, air pressure), a communication method with lower bandwidth and lower power consumption can be selected. Simultaneously, the communication status needs to be dynamically monitored during communication, and the most suitable communication method should be determined through algorithms, triggering a channel switching mechanism when necessary.

[0033] 2) Economic cost factors. The deployment, operation and maintenance costs of different communication methods vary significantly. It is necessary to combine the task scenario and communication requirements to select the more cost-effective solution while meeting the task performance requirements.

[0034] In each cycle, considering the mission type and economic cost of the unmanned surface vessel, a comprehensive score is calculated for the communication link corresponding to each communication method; the communication method corresponding to the communication link with the highest comprehensive score is selected as the most suitable communication method.

[0035] The formula used to calculate the overall score is as follows:

[0036] In the formula, Indicates the first i The overall score of each communication link. This represents the measured value of the current communication bandwidth, calculated using the Min-Max normalization formula, with a normalized score of 0-10. Min represents the minimum bandwidth required for the task, and Max represents the maximum value among all nominal bandwidths of the links. This represents the measured value of the current communication latency, calculated using the Min-Max standardization formula, resulting in a standardized score of 0-10. In this case, Min=0, and Max can be configured according to requirements. The communication cost of the communication link is represented by the Min-Max normalization formula, which calculates a normalized score of 0-10, where Min=0 and Max=100. and They are respectively and The weight, , and These are the weights for communication link performance and communication cost, respectively. .

[0037] The "Min-Max Standardization" formula is calculated as follows: Positive metrics are those whose scores are positively correlated with performance, such as coverage and communication bandwidth. The calculation formula is: Standardized Score = 10 * (Original Data - Min) / (Max - Min).

[0038] Negative metrics are those whose scores are negatively correlated with performance, such as transmission latency and communication cost. The calculation formula is: Standardized Score = 10 * (Max - Original Data) / (Max - Min).

[0039] Depending on the operational requirements of the unmanned surface vessel (USV), some parameters in the above algorithm can be configured specifically: Minimum score requirements can be set for communication bandwidth and latency based on the USV's mission needs. For example, when performing a video transmission task, transmitting 720p@25fps video typically requires at least 2Mbps. If the real-time link value is lower than this, the link will be considered unavailable.

[0040] weight value and , The communication link can be adjusted according to the actual project requirements to select the most suitable link. For example, if the unmanned surface vessel is intended to navigate in remote waters with less surrounding radio interference, the frequency can be appropriately reduced. Value; if the unmanned surface vessel is to operate near a busy waterway with a poor electromagnetic environment, the value should be appropriately increased. Value. When unmanned surface vessels (USVs) are performing critical missions, the focus is on communication link performance; therefore, the weight of communication costs in this context is... It can be lower than when unmanned surface vessels perform routine monitoring tasks, or even zero.

[0041] In one specific embodiment of this application, switching from the current application link to the selected most suitable communication method includes: The system determines whether the overall score of the communication link corresponding to the most suitable communication method exceeds the overall score of the current application link by a lag margin. If so, a switch is triggered. Before triggering the switch, the data that the UAV needs to transmit is stored locally, and pre-connection and authentication are performed with the most suitable communication method to complete the switch preparation. After the switch preparation is complete, the system switches from the current application link to the communication link corresponding to the most suitable communication method. During the switch from the current application link to the communication link corresponding to the most suitable communication method, if the control center detects that the communication link is switching, it sends the control command twice.

[0042] In the multi-system converged communication system of this application, a periodic evaluation strategy is adopted. Every certain period of time T is set, and the comprehensive score of the communication link corresponding to each communication method is calculated in each period. .

[0043] Simultaneously, a hysteresis handover strategy is adopted, introducing a hysteresis margin of 10% to prevent frequent ping-pong handovers caused by slight channel fluctuations. When there exists a link i with a comprehensive score... This is higher than the overall score of the links in the current application. If a certain hysteresis margin is exceeded, a handover is triggered. During the link handover process, brief communication interruptions (handover delay) are unavoidable, posing a potential risk to the continuous monitoring of the unmanned surface vessel. To mitigate this risk, this application designs the following strategy: Data caching and retransmission: Before the switchover starts, the data that the unmanned surface vessel needs to transmit will be cached locally. After the new link is established, the cached data will be retransmitted first to ensure the integrity of the transmitted data.

[0044] Parallel handshake: When a switch is required, a pre-connection and authentication process is first performed with the candidate node of the new link (parallel operation). Once ready, a rapid switch is performed to minimize the service interruption time.

[0045] Repeated transmission of control commands: When the control center sends control commands to the unmanned surface vessel (USV), if the USV is performing a link switch, the command may fail to be transmitted. To avoid this, the control commands will be transmitted twice, with a 1-second interval between them. Each control command contains a unique command number; the USV will only execute a command with the same number once.

[0046] This application provides a BeiDou-based multi-device fusion remote communication system for unmanned surface vessels. The system includes a conventional communication unit and an emergency communication unit. In each cycle, the conventional communication unit uses a link selection algorithm based on multi-index weighted evaluation to select the most suitable communication link and switches from the current application link to this link. A data loss prevention strategy is implemented during the link switching process, enabling communication with the control center in both emergency and non-emergency states. The emergency communication unit communicates with the control center via BeiDou short message service, enabling communication with the control center in emergency situations and facilitating the execution of different types of navigation missions. Therefore, this application can undertake communication tasks under complex environmental conditions and can quickly select the most suitable communication link and switch links in case of communication link failure, thus achieving remote communication in emergency situations.

[0047] This application also provides a BeiDou-based multi-system fusion remote communication method for unmanned surface vessels (USVs). By utilizing a BeiDou-based multi-device fusion remote communication system for USVs, the USV and the control center can communicate with each other and perform tasks in both emergency and non-emergency situations.

[0048] This application provides a BeiDou-based multi-system fusion remote communication method for unmanned surface vessels (USVs). This method utilizes a BeiDou-based multi-device fusion remote communication system for USVs to achieve remote communication. The communication system is designed with conventional and emergency communication units. The conventional communication unit selects the most suitable communication link for the communication mode in each cycle using a link selection algorithm based on multi-index weighted evaluation, and switches from the current application link to this link. A data loss prevention strategy is designed during the communication link switching process, enabling communication with the control center in both emergency and non-emergency states. The emergency communication unit communicates with the control center via BeiDou short message service, enabling communication with the control center in emergency situations, thus completing different types of navigation tasks. Therefore, the method proposed in this application can undertake communication tasks under complex environmental conditions and can quickly select the most suitable communication link and complete link switching when a communication link fails, thereby achieving remote communication in emergency situations.

[0049] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A Beidou-based multi-device fusion remote communication system for a water unmanned surface vehicle, characterized in that, The Beidou-based multi-device fusion remote communication system for the unmanned surface vehicle comprises: a conventional communication unit, configured to select a hardware communication device and a corresponding most suitable communication mode from a plurality of hardware communication devices according to a task requirement of the unmanned surface vehicle in each period, and switch from a current application link to the most suitable communication mode; communicate with a control center by using the most suitable communication mode, and receive operation instructions sent by the control center in an emergency state and a non-emergency state and return basic state information of the unmanned surface vehicle to the control center; an emergency communication unit, configured to receive control instructions sent by the control center in the emergency state and return the basic state information of the unmanned surface vehicle to the control center by using a communication mode of the emergency communication unit.

2. The Beidou-based multi-device fusion remote communication system for the unmanned surface vehicle according to claim 1, characterized in that, The conventional communication unit is loaded with a plurality of hardware communication devices, each of which corresponds to a communication mode, and the communication mode includes a 4G communication mode, a self-organizing network communication mode, a Tianhong communication mode and an Iridium communication mode. 3.The Beidou-based multi-device fusion remote communication system for the unmanned surface vehicle according to claim 2, characterized in that, The conventional communication unit is specifically configured to: select a most suitable communication mode from the communication modes corresponding to the plurality of hardware communication devices by using a multi-index weighted evaluation link selection algorithm in each period, considering a task requirement of the unmanned surface vehicle and an economic cost; switch from the current application link to a communication link corresponding to the selected most suitable communication mode.

4. The Beidou-based multi-device fusion remote communication system for the unmanned surface vehicle according to claim 3, characterized in that, The selecting the most suitable communication mode from the communication modes corresponding to the plurality of hardware communication devices by using the multi-index weighted evaluation link selection algorithm in each period, considering the task requirement of the unmanned surface vehicle and the economic cost, comprises: calculating a comprehensive score of each communication link corresponding to each communication mode in each period, considering a task type of the unmanned surface vehicle and the economic cost; selecting a communication mode corresponding to a communication link with the highest comprehensive score as the most suitable communication mode.

5. The Beidou-based multi-device fusion remote communication system for the unmanned surface vehicle according to claim 4, characterized in that, The comprehensive score is calculated according to a formula: wherein denotes the overall score of the i th communication link, denotes the measured value of the current communication bandwidth, denotes the measured value of the current communication latency, denotes the communication cost of the communication link, and are the weights of and respectively, , and are the weights of the communication link performance and the communication cost respectively, .

6. The Beidou-based multi-device fusion remote communication system for the unmanned surface vehicle according to claim 3, characterized in that, The switching from the current application link to the communication link corresponding to the selected most suitable communication mode comprises: judging whether a comprehensive score of the communication link corresponding to the most suitable communication mode exceeds a comprehensive score of the current application link by a hysteresis margin, and triggering the switching if yes; storing data to be returned by the unmanned surface vehicle locally and pre-connecting and authenticating with the most suitable communication mode before triggering the switching, to complete switching preparation; switching from the current application link to the communication link corresponding to the most suitable communication mode after waiting for the switching preparation to be completed.

7. The Beidou-based multi-device fusion remote communication system for the unmanned surface vehicle according to claim 6, characterized in that, In the process of switching from the current application link to the communication link corresponding to the most suitable communication mode, the control center sends the control instructions twice if it detects that the communication link is switching. 8.The Beidou-based multi-device fusion remote communication system for the unmanned surface vehicle of claim 1, wherein, The emergency communication unit uses Beidou short message communication as a communication link. 9.The Beidou-based multi-device fusion remote communication system for the unmanned surface vehicle of claim 1, wherein, The control instructions include an instruction number, and the basic state information includes a ship position, a ship speed and a heading.

10. A Beidou-based multi-system fusion remote communication method for a water surface unmanned ship, characterized in that, The Beidou-based multi-device fusion remote communication system for the unmanned surface vehicle is used to realize mutual communication between the unmanned surface vehicle and the control center in the emergency state and the non-emergency state, and execute a task.

Images