A link switching method and apparatus

Abstract

The embodiment of the application provides a link switching method and device, and relates to the technical field of unmanned aerial vehicle communication. The link switching method comprises the following steps: acquiring parameter values of each communication link of an unmanned aerial vehicle; based on the acquired parameter values, respectively evaluating and analyzing each communication link to obtain signal strength evaluation values; determining a second communication link to be switched to according to the determined signal strength evaluation values; controlling the first communication link and the determined second communication link to simultaneously transmit video data; wherein the video data transmitted when the determined second communication link is turned on is the same as the first communication link; and if the determined second communication link has continuously transmitted for a preset time length, the first communication link is turned off. Through the scheme, the real-time performance and transmission reliability of the video data of the unmanned aerial vehicle can be effectively ensured.

Description

Technical Field

[0001] This invention relates to the field of unmanned aerial vehicle (UAV) communication technology, and in particular to a link switching method and apparatus. Background Technology

[0002] In video data transmission scenarios involving drones, a dual-link backup method is typically used to ensure the reliability and real-time performance of video data transmission.

[0003] In related technologies, communication link switching is typically based on threshold judgment, that is, switching is triggered by comparing a single communication quality parameter with a fixed threshold. However, threshold-based judgment considers only one factor, which can easily lead to inaccurate switching decisions. As a result, the quality of the communication link after switching is not effectively improved, and thus the reliability and real-time performance of video data transmission cannot be guaranteed.

[0004] Ensuring the real-time performance and reliable transmission of drone video data is an urgent problem to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide a link switching method and apparatus to effectively ensure the real-time performance and transmission reliability of UAV video data. The specific technical solution is as follows:

[0006] In a first aspect, embodiments of this application provide a link switching method, including:

[0007] Obtain the parameter values ​​of each communication link of the UAV; wherein each communication link includes the first communication link currently used in the video data transmission process and at least one second communication link that is not currently in use;

[0008] Based on the obtained parameter values, each communication link is evaluated and analyzed to obtain a signal strength evaluation value; wherein, the evaluation and analysis includes initial evaluation according to parameter values ​​of different parameter types, and fusion processing of the evaluation values ​​obtained from the initial evaluation to obtain a signal strength evaluation value;

[0009] Based on the determined signal strength assessment value, determine the second communication link to which to switch;

[0010] The system controls the first communication link and the determined second communication link to transmit video data simultaneously; wherein, when the determined second communication link is activated, the video data transmitted is the same as that transmitted through the first communication link.

[0011] If the determined second communication link has been transmitting continuously for a preset duration, then the first communication link is shut down.

[0012] Secondly, embodiments of this application provide a link switching device, including:

[0013] The parameter acquisition module is used to acquire the parameter values ​​of each communication link of the UAV; wherein each communication link includes the first communication link currently used in the video data transmission process and at least one second communication link that is not currently in use;

[0014] The evaluation value determination module is used to evaluate and analyze each communication link based on the acquired parameter values ​​to obtain a signal strength evaluation value; wherein, the evaluation and analysis includes performing an initial evaluation according to parameter values ​​of different parameter types, and fusing the evaluation values ​​obtained from the initial evaluation to obtain a signal strength evaluation value;

[0015] The link determination module is used to determine the second communication link to which to switch based on the determined signal strength evaluation value;

[0016] The first control module is used to control the first communication link and the determined second communication link to transmit video data simultaneously; wherein, the video data transmitted when the determined second communication link is activated is the same as that transmitted when the second communication link is activated.

[0017] The second control module is used to shut down the first communication link if the determined second communication link has been transmitting continuously for a preset time.

[0018] Beneficial effects of the embodiments of the present invention:

[0019] In the solution provided by this invention, the evaluation and analysis of each communication link of the UAV includes initial evaluation based on parameter values ​​of different parameter types, and the evaluation values ​​obtained from the initial evaluation are fused. Therefore, each communication link can be comprehensively and accurately evaluated. Based on the signal strength evaluation value obtained from the evaluation and analysis, the determined second communication link has high communication link quality, providing a foundation for ensuring the real-time performance and transmission reliability of video data. Furthermore, after determining the second communication link to switch to, the first communication link and the determined second communication link are controlled to transmit video data simultaneously. When the determined second communication link is activated, the video data transmitted is the same as that of the first communication link. If the determined second communication link has been transmitting continuously for a preset duration, the first communication link is shut down. This ensures smooth link switching and avoids interruption of video data transmission. Therefore, this solution can effectively guarantee the real-time performance and transmission reliability of the UAV's video data.

[0020] Of course, implementing any product or method of the present invention does not necessarily require achieving all of the advantages described above at the same time. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained based on these drawings.

[0022] Figure 1 A flowchart illustrating a link switching method provided in an embodiment of this application;

[0023] Figure 2 This is another flowchart of a link switching method provided in an embodiment of this application;

[0024] Figure 3 A schematic diagram illustrating the working process of a dual-link adaptive switching system for UAV video transmission provided in an embodiment of this application;

[0025] Figure 4 This is a schematic diagram illustrating the signal strength assessment and handover decision-making process provided in an embodiment of this application;

[0026] Figure 5 This is a schematic diagram of the video data processing process provided in the embodiments of this application;

[0027] Figure 6 This is a schematic diagram of the structure of a link switching device provided in an embodiment of this application;

[0028] Figure 7 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art based on this application are within the scope of protection of the present invention.

[0030] Video data transmission from drones can utilize a single communication link, such as a 4G link (i.e., a link based on a 4G network) for direct streaming, or a dedicated wireless transmission link. This wireless transmission link can be COFDM (Coded Orthogonal Frequency Division Multiplexing) transmission, WiFi transmission, or similar methods. While 4G links offer wide coverage and easy access to public networks, they suffer from signal instability and significant latency fluctuations in remote areas, densely populated urban areas, or mobile scenarios. Dedicated wireless transmission links, on the other hand, offer high bandwidth and low latency, but have limited transmission distance and typically require a ground station to receive the data before forwarding it to the public network, increasing deployment complexity and cost.

[0031] In order to ensure the real-time performance and reliable transmission of video data, a dual-link backup method has been developed for video data transmission.

[0032] For video data transmission using dual-link backup, related technologies typically employ manual switching or threshold-based switching methods. Regardless of the method, the inventors found that stuttering, black screens, or interruptions easily occur during link switching, failing to truly guarantee the real-time performance and transmission reliability of video data. Ultimately, this fails to meet the high real-time requirements of applications such as inspections and live streaming. Furthermore, related technologies often lack signal strength normalization and comprehensive evaluation, leading to inaccurate switching decisions and impacting the real-time performance and transmission reliability of video data. Specifically, threshold-based switching triggers switching based on a comparison of a single communication quality parameter with a fixed threshold. However, this method considers only a single factor, easily resulting in inaccurate switching decisions. Consequently, the quality of the communication link after switching is not effectively improved, thus failing to guarantee the real-time performance and transmission reliability of video data.

[0033] Based on this, this application provides a link switching method and apparatus to effectively ensure the real-time performance and transmission reliability of UAV video data.

[0034] The following section first introduces a link switching method provided in an embodiment of this application.

[0035] This link switching method can be applied to a link switching device (i.e., a device used to switch links for a drone), which can be a drone or a drone control device.

[0036] Specifically, the entity implementing this link switching method can be a link switching device. When the link switching method is applied to different types of devices, the link switching device can be adapted to the corresponding program type; that is, the program type of the link switching device can be different. For example, when the link switching method is applied to a drone, the link switching device is a terminal-side program running on the drone. When the link switching method is applied to a control device, the link switching device is a control-side program running on the control device. This control-side program can cooperate with the drone to achieve the switching of the drone's communication link.

[0037] Furthermore, this link switching method can be applied to scenarios requiring high-reliability video backhaul, such as drone inspection, security monitoring, and emergency command, but it is not limited to these scenarios. This application does not limit the specific scenarios.

[0038] One link switching method may include:

[0039] Obtain the parameter values ​​of each communication link of the UAV; wherein each communication link includes the first communication link currently used in the video data transmission process and at least one second communication link that is not currently in use;

[0040] Based on the obtained parameter values, each communication link is evaluated and analyzed to obtain a signal strength evaluation value; wherein, the evaluation and analysis includes initial evaluation according to parameter values ​​of different parameter types, and fusion processing of the evaluation values ​​obtained from the initial evaluation to obtain a signal strength evaluation value;

[0041] Based on the determined signal strength assessment value, determine the second communication link to which to switch;

[0042] The system controls the first communication link and the determined second communication link to transmit video data simultaneously; wherein, when the determined second communication link is activated, the video data transmitted is the same as that transmitted through the first communication link.

[0043] If the determined second communication link has been transmitting continuously for a preset duration, then the first communication link is shut down.

[0044] In the solution provided by this invention, the evaluation and analysis of each communication link of the UAV includes initial evaluation based on parameter values ​​of different parameter types, and the evaluation values ​​obtained from the initial evaluation are fused. Therefore, each communication link can be comprehensively and accurately evaluated. Based on the signal strength evaluation value obtained from the evaluation and analysis, the determined second communication link has high communication link quality, providing a foundation for ensuring the real-time performance and transmission reliability of video data. Furthermore, after determining the second communication link to switch to, the first communication link and the determined second communication link are controlled to transmit video data simultaneously. When the determined second communication link is activated, the video data transmitted is the same as that of the first communication link. If the determined second communication link has been transmitting continuously for a preset duration, the first communication link is shut down. This ensures smooth link switching and avoids interruption of video data transmission. Therefore, this solution can effectively guarantee the real-time performance and transmission reliability of the UAV's video data.

[0045] like Figure 1 As shown in the embodiments of this application, a link switching method may include:

[0046] S101, Obtain the parameter values ​​of each communication link of the UAV;

[0047] Each communication link includes a first communication link currently used in the video data transmission process and at least one second communication link that is not currently in use.

[0048] S102, Based on the obtained parameter values, each communication link is evaluated and analyzed to obtain a signal strength evaluation value;

[0049] The evaluation analysis includes performing an initial evaluation according to parameter values ​​of different parameter types, and fusing the evaluation values ​​obtained from the initial evaluation to obtain a signal strength evaluation value.

[0050] S103, Based on the determined signal strength evaluation value, determine the second communication link to which to switch;

[0051] S104, control the first communication link and the determined second communication link to transmit video data simultaneously;

[0052] The video data transmitted when the second communication link is activated is the same as that transmitted when the first communication link is activated.

[0053] S105, if the determined second communication link has been transmitting for a preset duration, then the first communication link is closed.

[0054] During the video data transmission process of the drone, the drone's video data is transmitted to a server (such as a server on the public network) via a communication link. This server then performs operations such as recording and distributing the video data. For example, the server can provide feedback to users who require video data preview, thereby distributing the video data to the user for real-time preview. Each communication link of the drone can be at least two communication links applicable to drone communication. The specific number of links can be set according to the actual scenario, and this application does not limit this. Furthermore, when there are two communication links for the drone, this link switching method can be understood as a dual-link adaptive switching method for video transmission based on these two communication links (such as a wireless image transmission link and a 4G link).

[0055] Furthermore, each communication link of the UAV may include a first communication link and at least one second communication link. The "first" in the first communication link and the "second" in the second communication link merely distinguishes, by naming, the communication link currently in use during the UAV's video data transmission process (which can be called the main streaming channel) and the unused communication link (which can be called the auxiliary streaming channel), and has no limiting meaning. It is understood that the first communication link is an established link that transmits video data, while the second communication link may be an established link that does not transmit video data. Therefore, for the first communication link, the parameter values ​​of the first communication link can be obtained based on the transmission status of video data transmitted through the first communication link. For the second communication link, the parameter values ​​of the second communication link can be obtained by sending test packets. It should be emphasized that any method capable of obtaining the parameter values ​​of each communication link of the UAV can be applied to the embodiments of this application; furthermore, for each communication link, at least one parameter value of a certain parameter type can be obtained.

[0056] Furthermore, for example, in one implementation, different communication links can obtain parameter values ​​of the same parameter type. For example, in other implementations, considering that each communication link has its own link characteristics (e.g., affected by the link type), for each communication link of the UAV, a parameter type specific to that communication link can be set for link evaluation. In this case, the parameter type of the obtained parameter values ​​for that communication link is the parameter type set for that communication link, thus providing a basis for further improving the accuracy of link evaluation. For example, if each communication link includes a wireless image transmission link and a cellular network-based communication link (such as a 4G link), then the obtained parameter values ​​for the wireless image transmission link can be selected from parameters such as MCS (Modulation and Coding Scheme), bit error rate, and round-trip delay. The obtained parameter values ​​for the cellular network-based communication link can be selected from parameters such as RSRP (Reference Signal Received Power), RSSI (Received Signal Strength Indicator), SNR (Signal-to-Noise Ratio), bandwidth, packet loss rate, and round-trip delay. It can be understood that different MCS values ​​correspond to different combinations of modulation schemes and coding strategies, representing different wireless transmission strategies; a larger value indicates a higher transmission rate but weaker anti-interference capability.

[0057] Furthermore, after enabling the link switching function, S101 can be executed upon meeting a predetermined trigger condition to enter the link switching analysis process. For example, in one implementation, link switching analysis can be performed periodically. In this case, the trigger condition can be entering a new cycle. At this time, the parameter values ​​of each communication link of the UAV are periodically acquired, thereby periodically performing link switching analysis. For example, in another implementation, S101 can be triggered when a predetermined object of interest is detected in the video data collected by the UAV. In this case, the trigger condition can be the detection of the object of interest in the video data. The description of the trigger condition in this application is merely an example and should not be construed as limiting the embodiments of this application.

[0058] After obtaining the parameter values ​​of each communication link, the quality of each communication link can be evaluated based on the obtained parameter values. That is, each communication link is evaluated and analyzed separately to obtain a signal strength evaluation value. In order to comprehensively and accurately evaluate each communication link, the evaluation analysis adopted in this application embodiment may include: performing an initial evaluation according to parameter values ​​of different parameter types, and fusing the evaluation values ​​obtained from the initial evaluation to obtain a signal strength evaluation value. That is, for each communication link, there are two processes: initial evaluation and fusion processing. The initial evaluation is an evaluation related to parameter types based on parameter values ​​of different parameter types (for example, parameter values ​​of different parameter types are evaluated and processed according to their respective initial evaluation methods). The fusion processing is used to merge the evaluation values ​​related to parameter types. Through this fusion processing, it is possible to unify each communication link to the same evaluation dimension to evaluate the communication link quality of each communication link. For example, through fusion processing, the signal strength evaluation value of each communication link can be a value within a set evaluation value range.

[0059] It should be emphasized that any method that can perform initial evaluation according to parameter values ​​of different parameter types can be applied to the embodiments of this application, and any method that can fuse the evaluation values ​​obtained from the initial evaluation can be applied to the embodiments of this application; for the sake of clarity and layout, other embodiments will be described in the following examples.

[0060] Furthermore, after obtaining the signal strength assessment values ​​of each communication link, the second communication link to be switched to can be determined based on the determined signal strength assessment values. And, after determining the second communication link to be switched to, the link switching can be performed according to a set method: controlling the first communication link and the determined second communication link to transmit video data simultaneously, and the video data transmitted when the determined second communication link is activated is the same as that transmitted through the first communication link; and, if the determined second communication link has been transmitting continuously for a preset duration, then the first communication link is shut down. It is understood that during the link switching process, dual-link transmission can be performed in this embodiment, and the duration of dual-link transmission is the preset duration.

[0061] It should be noted that the process of determining the second communication link to be switched to based on the determined signal strength assessment value is as follows: analyze whether there is a communication link that meets the switching requirements among the at least one second communication link. Therefore, if there is no such link, the second communication link to be switched to cannot be determined, and the first communication link will continue to be used for video data transmission; if there is such a link, the second communication link to be switched to can be determined.

[0062] There are several ways to determine the second communication link to be switched to based on the determined signal strength evaluation value. For example, one method is to analyze the relationship and difference between the signal strength evaluation value of at least one second communication link and the signal strength evaluation value of the first communication link, and then filter out second communication links whose signal strength evaluation value is greater than that of the first communication link and whose difference is greater than a set threshold. If a second communication link can be selected, it is chosen as the second communication link to be switched to. For clarity and layout, the specific implementation of determining the second communication link to be switched to based on the determined signal strength evaluation value will be described in conjunction with other embodiments.

[0063] Furthermore, in this embodiment of the application, the link switching is performed in this manner, which allows the new link and the original link to simultaneously send video data for a certain duration (i.e., a preset duration), and then the new link continues to send data while the original link is disconnected. Since the new link and the original link can have a certain duration of data overlap, the problem of data interruption caused by the original link being disconnected while the new link is transmitting data in time can be avoided during the switching process. This further makes the switching imperceptible to the video playback end (or preview end).

[0064] The aforementioned preset duration (also known as preset retention duration) can be set according to actual conditions. It is understood that, to prevent the waste of data resources caused by excessive redundant data, the preset duration can, for example, be 2 seconds, 3 seconds, etc. Furthermore, the server can receive two copies of the video data of the preset duration and can merge the received video data of the preset duration to form usable video data ready for distribution.

[0065] Furthermore, it is understandable that if the link switching device is a drone, S101 and S105 can be executed locally by the drone to achieve the corresponding process; if the link switching device is a control device, then S101 and S105 can be executed separately by the link switching device and the drone to achieve the corresponding process.

[0066] In the solution provided by this invention, the evaluation and analysis of each communication link of the UAV includes initial evaluation according to parameter values ​​of different parameter types, and the evaluation values ​​obtained from the initial evaluation are fused. Therefore, each communication link can be comprehensively and accurately evaluated. Based on the signal strength evaluation value obtained from the evaluation and analysis, the determined second communication link has high communication link quality, providing a foundation for ensuring the real-time performance and transmission reliability of video data. Furthermore, after determining the second communication link to switch to, the first communication link and the determined second communication link are controlled to transmit video data simultaneously. When the determined second communication link is activated, the video data transmitted is the same as that of the first communication link. If the determined second communication link has been transmitting continuously for a preset duration, the first communication link is shut down. This ensures smooth link switching and avoids interruption of video data transmission. Therefore, this solution can effectively guarantee the real-time performance and transmission reliability of the UAV's video data.

[0067] In one possible embodiment, determining the second communication link to be switched to based on the determined signal strength assessment value includes:

[0068] Based on the determined signal strength assessment value, a second communication link that meets the target handover conditions is selected as the second communication link to be handed over to; wherein,

[0069] The conditions for the target switching include:

[0070] The signal strength assessment value is greater than that of the first communication link and the switchable auxiliary condition is met;

[0071] or,

[0072] When the anti-interference capability of the first communication link is not higher than that of the second communication link, the conditions for the target switching include:

[0073] The signal strength assessment value is greater than that of the first communication link.

[0074] In this embodiment, the determination of the second communication link to which the user is to switch can be based on the set target switching conditions.

[0075] In one implementation, the target switching condition may include: the signal strength assessment value is greater than the first communication link and the switchable auxiliary condition is met.

[0076] Considering the uncertainty in the relationship between the anti-interference capability (link stability) of the first communication link and the at least one second communication link—that is, the anti-interference capability of the first communication link may be higher or lower than that of the second communication link—this implementation, to adapt to this uncertainty and ensure that the link quality of the switched-off communication link is higher than that of the communication link before the switch (i.e., the link quality after the switch is effectively improved), uses a signal strength evaluation value greater than that of the first communication link and the satisfaction of the switchable auxiliary condition as the target switch condition. Ensuring that the quality of the switched-off communication link is improved from multiple dimensions helps to improve the accuracy of the switch decision. The switchable auxiliary condition can be set according to the actual situation; any condition that can further characterize the switchability of the second communication link (i.e., the communication link quality after the switch is improved relative to before the switch) can be used as a switchable auxiliary condition.

[0077] In another implementation, if the anti-interference capability of the first communication link is not higher than that of the second communication link, the condition for target switching may include: the signal strength assessment value is greater than that of the first communication link.

[0078] In this implementation, during the process of determining the second communication link to be switched to, anti-interference capability and signal strength assessment values ​​can be used as a basis to ensure that the link quality of the switched communication link is higher than that of the original communication link (i.e., the link quality after the switch is effectively improved), which helps to improve the accuracy of the switching decision. It should be noted that the relationship between the anti-interference capabilities of the various communication links of the UAV (e.g., the anti-interference capability of the wireless image transmission link is higher than that of the 4G link) can be predetermined and stored. Therefore, during the link switching process, the relationship between the anti-interference capabilities of the various communication links of the UAV can be obtained to determine the second communication link to be switched to.

[0079] It should be noted that, if there are multiple second communication links that meet the target switching conditions, one of them can be selected as the second communication link to be switched to, according to a predetermined selection rule. For example, the predetermined selection rule may include random selection, prioritizing the selection of links with high anti-interference capability, prioritizing the selection of links with lower cost, etc. The specific selection rule can be set according to the actual situation, and this application does not make specific limitations.

[0080] In this embodiment, based on the determined signal strength evaluation value and the target switching conditions, the second communication link to be switched to is determined. Furthermore, the target switching conditions are all set to ensure that the link quality of the switched communication link is effectively improved. Therefore, this embodiment ensures that the determined second communication link to be switched to has high communication link quality, thus providing a basis for more accurate link switching (i.e., switching decisions), and ultimately further guaranteeing the real-time performance and transmission reliability of the UAV's video data.

[0081] In one possible embodiment, the method for determining whether the second communication link meets the switchable auxiliary conditions may include:

[0082] The first evaluation index corresponding to the second communication link is greater than the preset first index threshold; wherein, the first evaluation index corresponding to the second communication link represents the difference between the signal strength evaluation value of the second communication link and the signal strength evaluation value of the first communication link;

[0083] or,

[0084] The target parameter value of the second communication link is greater than the target parameter value of the first communication link, and the second evaluation index is greater than the preset second index threshold; wherein, the target parameter value of the second communication link and the target parameter value of the first communication link are both parameter values ​​characterizing the link network environment, and the second evaluation index characterizes the difference between the target parameter value of the second communication link and the target parameter value of the first communication link.

[0085] Among them, the factors to be considered for the second communication link to meet the switchable auxiliary conditions can be one or two. For example, it is reasonable to consider only the first evaluation index mentioned above, only the target parameter value, or to combine the first evaluation index and the target parameter value at the same time.

[0086] The difference between the signal strength assessment value of the second communication link and the signal strength assessment value of the first communication link can be characterized by the difference or the ratio of the signal strength assessment values. In other words, the first assessment index can be characterized by either a difference or a ratio. For example, if the first assessment index is characterized by the difference in signal strength assessment values, then the first assessment index being greater than a preset first index threshold can be defined as the first assessment index being greater than a predetermined difference in signal strength assessment values, i.e., the difference threshold. If the first assessment index is characterized by the ratio of signal strength assessment values, then the first assessment index being greater than a preset first index threshold can be defined as the first assessment index being greater than a predetermined ratio threshold, where the ratio threshold is a value greater than 1, for example, 1.2 or 1.3, etc.

[0087] Additionally, for example, the target parameter value can be a parameter that characterizes the network environment, such as bandwidth or round-trip time, and is not limited here. A second evaluation metric used to characterize the magnitude of the difference in the target parameter values ​​can also be used to characterize them using differences or ratios of the target parameter values.

[0088] Taking the communication links of a drone, including the wireless image transmission link and the 4G link, as an example, if the wireless image transmission link is the first communication link and the 4G link is the second communication link, the target switching conditions to be met include: the signal strength evaluation value of the 4G link is greater than the signal strength evaluation value of the wireless image transmission link, and the ratio of the signal strength evaluation value of the 4G link to the signal strength evaluation value of the wireless image transmission link is greater than 1.2. Then, after obtaining the signal strength evaluation value S_VT of the wireless image transmission link and the signal strength evaluation value S_4G of the 4G link, if it is detected that the target switching conditions required to switch from the wireless image transmission link to the 4G link are met: S_4G>S_VT and S_4G / S_VT>1.2, then it can be triggered to control the drone to switch from the wireless image transmission link to the 4G link, that is, the 4G link is the second communication link to be switched to; otherwise, the wireless image transmission link is maintained.

[0089] Taking the communication links of the drone, including the wireless image transmission link and the 4G link, as an example, if the 4G link is the first communication link and the wireless image transmission link is the second communication link, the target switching conditions to be met include: the signal strength evaluation value of the wireless image transmission link is greater than the signal strength evaluation value of the 4G link. Then, after obtaining the signal strength evaluation value S_VT of the wireless image transmission link and the signal strength evaluation value S_4G of the 4G link, if it is detected that the target switching condition required to switch from the 4G link to the wireless image transmission link is met: S_VT>S_4G, then it can be triggered to control the drone to switch from the 4G link to the wireless image transmission link, that is, the wireless image transmission link is the second communication link to be switched to; otherwise, the 4G link is maintained.

[0090] In other words, the switching logic between the wireless image transmission link and the 4G link is as follows: it does not wait until the 4G or image transmission signal is very weak before switching. Instead, if the signal strength of the 4G link is slightly stronger than that of the wireless image transmission link (the first communication link is the wireless image transmission link and the second communication link is the 4G link), the wireless image transmission link can still be maintained. However, if the signal strength of the wireless image transmission link is slightly stronger than that of the 4G link (the first communication link is the 4G link and the second communication link is the wireless image transmission link), it directly switches to the wireless image transmission link. This switching logic effectively prevents black screens, stuttering, and other issues during switching.

[0091] In this embodiment, the specific implementation of the second communication link satisfying the switchable auxiliary conditions can better verify whether it is possible to switch from the first communication link to the second communication link. This provides a basis for more accurate link switching (i.e., switching decision) and can ultimately further ensure the real-time performance and transmission reliability of the UAV's video data.

[0092] In one possible embodiment, the predetermined parameters of each communication link include: at least one primary parameter value and at least one secondary parameter value; the primary parameter values ​​are different for different communication links;

[0093] exist Figure 1 On the basis of, such as Figure 2 As shown, step S102 above may include S1021-S1023:

[0094] S1021, based on the acquired at least one main parameter value and the evaluation method set for the at least one main parameter value, determine a first evaluation value for each of the communication links;

[0095] S1022, based on the acquired at least one auxiliary parameter value, and according to the evaluation method set for each auxiliary parameter value, determine at least one second evaluation value for each communication link.

[0096] S1023, based on the determined first evaluation value and second evaluation value, calculate the signal strength evaluation value for each of the communication links.

[0097] Based on the characteristics of each communication link, the parameter values ​​of each communication link can have multiple parameter types. Correspondingly, based on the parameter type, the parameter values ​​of each communication link can include primary parameter values ​​and secondary parameter values, and the number of primary parameter values ​​and secondary parameter values ​​can be one or more. Moreover, the primary parameter values ​​are different for different communication links. That is to say, the primary parameter values ​​are the parameter values ​​that are more adapted to the link characteristics and can better reflect the link characteristics (or the parameter values ​​that have a greater impact on the quality of the communication link).

[0098] For example, in one optional implementation, each communication link includes a wireless image transmission link and a cellular network-based communication link (such as a 4G link, a 5G link, etc.); the at least one primary parameter value of the wireless image transmission link may include: MCS (Modulation and Coding Scheme), and correspondingly, the at least one secondary parameter value of the wireless image transmission link may include: bit error rate and / or round-trip delay; and the at least one primary parameter value of the cellular network-based communication link may include: Reference Received Power (RSRP) and / or Signal-to-Noise Ratio (SNR), and correspondingly, the at least one secondary parameter value of the cellular network-based communication link may include: Received Signal Strength Indication (RSSI), bandwidth, packet loss rate, and round-trip delay.

[0099] After setting the primary and secondary parameter values ​​for each communication link, in the process of determining the signal strength evaluation value, two types of signal strength evaluation values ​​can be calculated for each communication link: a first evaluation value determined based on the primary parameter value and a second evaluation value determined based on the secondary parameter value. Furthermore, for the at least one primary parameter value of the communication link, there can be a corresponding first evaluation value, which is a signal strength reflected by combining the at least one primary parameter value. For the at least one secondary parameter value of the communication link, each secondary parameter value can correspond to a second evaluation value, that is, each second evaluation value is a signal strength reflected by the corresponding secondary parameter value alone.

[0100] It should be noted that the joint calculation of the main parameter values ​​of the communication link integrates the synergistic effect of the core evaluation dimensions to form a first evaluation value reflecting the core link performance, ensuring the dominant position of the main parameter values. Each auxiliary parameter value is calculated independently to obtain a second evaluation value, which can supplement and correct for subdivided scenarios not covered by the main parameter values, avoiding mutual interference between the core evaluation and the detailed evaluation. This design ensures both the comprehensiveness and robustness of the signal strength evaluation of the communication link, and clearly defines the functional boundaries of the main / auxiliary parameter values, making the evaluation logic more in line with actual application needs. In addition, the design of "jointly forming the first evaluation value" integrates the synergistic effect of at least one main parameter value into a core indicator, avoiding the one-sidedness of a single main parameter value, while ensuring that its impact on the final evaluation result is far greater than that of a single auxiliary parameter value (a single auxiliary parameter value corresponds to only an independent second evaluation value).

[0101] After determining the first and second evaluation values, the signal strength evaluation value of the communication link can be calculated based on these values ​​using a predetermined calculation method, such as a weighted method. It is understood that the weight of the first evaluation value can be greater than the weight of the second evaluation value during the weighted calculation. This allows the evaluation result determined based on the primary parameter value to play a more dominant role in the fusion process compared to the evaluation result determined based on the secondary parameter value, thus ensuring that the signal strength evaluation process is adapted to the link characteristics.

[0102] For a communication link, there can be multiple ways to determine the first evaluation value, such as normalizing the at least one main parameter value and then weighting it based on the normalization result. Similarly, there can be multiple ways to determine the second evaluation value, such as analyzing the parameter value range in which each auxiliary parameter value lies, and then using the value corresponding to the analyzed parameter value range as the second evaluation value corresponding to the auxiliary parameter value. For clarity and layout, other methods for determining the first and second evaluation values ​​will be described in subsequent embodiments.

[0103] In this embodiment, by setting primary and secondary parameter values ​​for each communication link, and performing signal strength evaluation based on these values ​​to obtain a first evaluation value and a second evaluation value, the signal strength evaluation value for each communication link is determined by combining the first and second evaluation values. This ensures that the calculation of the signal strength evaluation value more closely reflects the characteristics of the communication link, guaranteeing its accuracy. This provides a data foundation for more accurate link switching (i.e., switching decisions), ultimately further ensuring the real-time performance and transmission reliability of the UAV's video data.

[0104] In one possible embodiment, determining the first evaluation value of each communication link (i.e., the step described in S1021 above) based on the acquired at least one main parameter value and the evaluation method set for the at least one main parameter value may include the following steps:

[0105] Step A1: For each communication link, if the value of at least one main parameter of the communication link satisfies the corresponding value condition, then the maximum value within the range of evaluation values ​​is selected as the first evaluation value of the communication link.

[0106] Step A2: If there is a main parameter value among the at least one main parameter value of the communication link that does not meet the corresponding value condition, then the minimum value within the range of the evaluation value is selected as the first evaluation value of the communication link.

[0107] The condition for each main parameter value is that the signal strength meets the preset reliability strength range.

[0108] In this embodiment, each of the at least one primary parameter value of the communication link can be assigned a value condition (characterizing that the signal strength meets the reliable transmission requirements). Thus, when each primary parameter value of the communication link satisfies its corresponding value condition, from the perspective of the evaluation dimension corresponding to each primary parameter value, it indicates that the communication link meets the reliable transmission requirements. Therefore, the maximum value within the evaluation value range can be selected as the first evaluation value of the communication link; otherwise, the minimum value within the evaluation value range can be selected as the first evaluation value of the communication link. This method of selecting the first evaluation value allows the at least one primary parameter value of the communication link to play a dominant role, ensuring a significant impact on the evaluation of signal strength. It should be noted that when there are multiple primary parameter values, each primary parameter value satisfies its corresponding value condition.

[0109] Taking the various communication links of a drone, including the wireless image transmission link and the cellular network-based communication link, as an example, the process of determining the above-mentioned first evaluation value is introduced:

[0110] When the evaluation value ranges from [0,4], assuming that the at least one main parameter of the wireless image transmission link includes a first parameter value and a second parameter value, if the first parameter value satisfies the corresponding value condition and the second parameter value satisfies the corresponding value condition, then the first evaluation value of the wireless image transmission link can be set to 4; and assuming that the at least one main parameter of the cellular network-based communication link includes a third parameter value, if the third parameter value does not satisfy the corresponding value condition, then the first evaluation value of the 4G link can be set to 0.

[0111] Using the various communication links of a drone, including the wireless image transmission link and the 4G link, as specific examples, the method for determining the first evaluation value is introduced:

[0112] When the evaluation value range is [0,4], if the at least one main parameter of the 4G link includes RSRP and SNR, the parameter values ​​of RSRP and SNR of the 4G link and the conditions for taking the values ​​can be assigned based on the empirical range of the two types of parameters. For example, RSRP>-85 and SNR>20 means the signal is excellent. In this case, the first evaluation value of the 4G link can be 4; otherwise, it can be 0.

[0113] If the at least one main parameter of the wireless image transmission link may include: MCS, and the specific value and value conditions of MCS can be assigned based on an empirical range, for example, if the specific value of MCS is greater than or equal to a certain set value, the first evaluation value of the wireless image transmission link can be 4; otherwise, the first evaluation value of the wireless image transmission link corresponding to each main parameter can be 0.

[0114] In this embodiment, the first evaluation value is set based on the maximum and minimum values ​​in the range of evaluation values, and in combination with whether the at least one main parameter value of the communication link meets the corresponding value conditions. This allows the at least one main parameter value of the communication link to play a leading role in the signal strength evaluation process, thereby obtaining a more accurate signal strength evaluation value.

[0115] In one possible embodiment, determining at least one second evaluation value for each communication link based on the acquired at least one auxiliary parameter value and according to the evaluation method set for each auxiliary parameter value (i.e., the step described in S1022 above) may include the following steps:

[0116] Step B1: Obtain the target mapping relationship corresponding to each auxiliary parameter value of each of the communication links; wherein, the target mapping relationship corresponding to each auxiliary parameter value is: a mapping relationship that represents the auxiliary parameter value and the evaluation value in the range of the evaluation value;

[0117] Step B2: Based on the obtained target mapping relationship, map each auxiliary parameter value of each communication link to the range of the evaluation value to obtain at least one second evaluation value for each communication link.

[0118] For each communication link, each auxiliary parameter value can be associated with a target mapping relationship. This target mapping relationship can be represented by a function (input is an auxiliary parameter value, output is an evaluation value) or by a relation table. Thus, after obtaining the auxiliary parameter value, the corresponding evaluation value can be determined based on the target mapping relationship. It is understood that the target mapping relationship is used to map auxiliary parameter values ​​to the range of evaluation values. The target mapping relationship for each auxiliary parameter value can be a mapping relationship for the target parameter type to which the auxiliary parameter value belongs. That is, any auxiliary parameter value belonging to the target parameter type and having any value can be mapped through this target mapping relationship; the specific form is not specifically limited.

[0119] Understandably, for each auxiliary parameter value, if the larger the value, the better the signal strength of the communication link, then the target mapping relationship corresponding to that auxiliary parameter value is positively correlated; conversely, if the larger the value, the worse the signal strength of the communication link, then the target mapping relationship corresponding to that auxiliary parameter value is negatively correlated.

[0120] It should be noted that for each auxiliary parameter value, the range of the auxiliary parameter value is based on the value in its corresponding empirical range segment, and the corresponding target mapping relationship is used to process the auxiliary parameter value into the same evaluation value range, such as [0,4] as mentioned above.

[0121] Assuming the evaluation value ranges from [0,4], taking a 4G link as an example, assuming the at least one auxiliary parameter value includes: bandwidth, packet loss rate, and round-trip delay, with the empirical range of bandwidth being (0-10Mbps), the empirical range of packet loss rate being (0%-100%), and the empirical range of round-trip delay being (30-200ms); through the corresponding target mapping relationship, the bandwidth, packet loss rate, and round-trip delay are respectively processed into the range of [0,4]. Taking a wireless image transmission link as an example, assuming the auxiliary parameters of the wireless image transmission link include bit error rate and delay, then through the corresponding target mapping relationship, the bit error rate and round-trip delay are processed into the range of [0,4].

[0122] In this embodiment, for the at least one auxiliary parameter value of any communication link, a respective target mapping relationship is set. In this way, at least one second evaluation value of each communication link is calculated through the respective target mapping relationship, thereby making the accuracy of the calculated second evaluation value of each communication link higher.

[0123] In one possible embodiment, calculating the signal strength evaluation value for each communication link based on the determined first and second evaluation values ​​(i.e., the step described in S1023 above) may include the following steps:

[0124] Step C1: Determine a weighted calculation method that matches the range of the evaluation value; wherein the weighted calculation method is used to ensure that the value obtained by the weighted calculation is within the range of the evaluation value.

[0125] Step C2: Based on the weighted calculation method, the determined first evaluation value and second evaluation value are weighted to obtain the signal strength evaluation value of each communication link; wherein the signal strength evaluation value is within the range of the evaluation value.

[0126] For each communication link of the UAV, after obtaining a first evaluation value and at least one second evaluation value for that communication link, a weighted calculation can be performed based on the two types of signal strength evaluation values ​​according to a weighted algorithm to obtain a signal strength evaluation value for that communication link that falls within the range of evaluation value values. In other words, for each communication link, signal strength normalization processing is performed based on the corresponding first and second evaluation values, i.e., normalized to the range of evaluation value values, thereby obtaining comparable signal strength evaluation values ​​for each communication link.

[0127] Understandably, in practical applications, during weighted calculations, the weight of the first evaluation value can be higher than that of the second evaluation value to enhance the proactive role of the main parameter value in signal strength evaluation. The specific weight values ​​can be set according to the specific application and are not limited here.

[0128] In this embodiment, for each communication link, based on the calculated first evaluation value and the second evaluation value, a weighted method is used to normalize them to the same evaluation value range, thereby calculating a comparable and accurate signal strength evaluation value for each communication link.

[0129] In one possible embodiment, the video data transmission process may include the following steps:

[0130] Step D1: Based on the first plugin element in the multimedia processing framework GStreamer, acquire the video data collected by the drone;

[0131] Step D2: Decode the video data to obtain decoded data;

[0132] Step D3: The decoded data is transmitted to the second plugin element in the GStreamer; wherein the second plugin element is used to encode and encapsulate the decoded data.

[0133] Step D4: Control the current communication link to transmit the encapsulated video data.

[0134] In this embodiment, a first plug-in element in the multimedia processing framework GStreamer is controlled to obtain video data from the acquisition module of the drone and decode the obtained video data to obtain decoded data. The decoded data is then transmitted to a second plug-in element in GStreamer so that the second plug-in element encodes and encapsulates the decoded data and transmits the encapsulated video data through the currently used communication link. For example, the second plug-in element is a plug-in element that applies the WebRTC protocol.

[0135] GStreamer is a cross-platform multimedia processing framework (developed in C, supporting Python / Go bindings; Python is an interpreted, dynamically typed, weakly typed high-level programming language, and Go, also known as Golang, is a compiled, statically typed, strongly typed programming language). Its core function is to handle the entire process of audio and video acquisition, encoding, decoding, transmission, and rendering. Key features include a "plugin + pipeline" architecture, with a large number of built-in audio and video codecs and protocol plugins, allowing for flexible assembly into any audio and video processing flow. Applications include audio and video player development, live streaming push / pull, video conferencing, and audio and video transcoding. The protocols upon which the plugins are based can include, but are not limited to, RTP (Real-time Transport Protocol), RTSP (Real-Time Streaming Protocol), RTMP (Real-Time Messaging Protocol), and WebRTC (Web Real-Time Communication).

[0136] Specifically, WebRTC is a real-time audio and video communication standard (including protocols and APIs). Its core features include native support for low-latency P2P (Peer-to-Peer) audio and video transmission, and built-in capabilities such as NAT (Network Address Translation) traversal, audio and video encoding, and encryption. Its application scenarios can include web-based video calls, real-time interactive live streaming, online education, and remote control. Among these, NAT traversal is a network communication technology used to resolve the issue of two peer nodes located on different internal networks passing through NAT devices.

[0137] In this embodiment, the GStreamer+WebRTC framework can be used to decouple encoding / decoding, transmission, and control. Furthermore, the GStreamer+WebRTC standardized streaming media processing workflow offers strong compatibility and good scalability. It is understood that by combining GStreamer and WebRTC, audio and video acquisition, encoding, decoding, and rendering can be processed based on GStreamer, while low-latency real-time transmission can be achieved based on the WebRTC protocol (replacing traditional RTSP / RTP, etc.). Moreover, GStreamer has built-in second plugin elements (such as the webrtcbin plugin) specifically for interfacing with the WebRTC protocol, eliminating the need to manually implement complex ICE (Interactive Connectivity Establishment) / STUN (SessionTraversal Utilities for NAT) / TURN logic (using relays for NAT traversal).

[0138] Specifically, the multimedia processing framework GStreamer can deploy at least a first plugin element and a second plugin element. The first plugin element obtains video data from the drone's acquisition module, decodes the obtained video data to obtain decoded data, and transmits the decoded data to the second plugin element in GStreamer. Correspondingly, the second plugin element encodes and encapsulates the decoded data, and then transmits the encapsulated video data through the currently used communication link. The second plugin element is a plugin element that applies the WebRTC protocol. The first and second plugin elements can each implement their respective functions. Changing the function of either the first or second plugin element does not affect the function of the other plugin element; that is, the first and second plugin elements do not need to be coupled together.

[0139] Additionally, it should be noted that, for example, the second plug-in element based on the WebRTC protocol can encode the decoded data transmitted by the first plug-in element into an H.264 / H.265 video stream; and the encoded video data can be directly encapsulated into a real-time stream in WebRTC format and transmitted end-to-end via RTP / SRTP.

[0140] Alternatively, in an optional implementation, the link switching device may issue a switching command to the second plug-in element, so that the second plug-in element responds to the switching command to execute the above-described S104-S105.

[0141] In this implementation, since the second plug-in element is used to transmit encapsulated video data, when controlling the drone to switch links, a switching command can be sent to the second plug-in element so that the second plug-in element responds to the switching command and performs link switching.

[0142] In this embodiment, during video data transmission, the GStreamer+WebRTC framework (also known as a standardized framework) is used to decouple encoding / decoding, transmission, and control; and by combining WebRTC's NACK (Negative Acknowledgment) and FEC (Forward Error Correction) anti-packet loss mechanisms, the video is ensured to be continuous and uninterrupted during switching.

[0143] To better understand the link switching method provided in the embodiments of this application, the following uses the communication links of a UAV, including 4G links and wireless image transmission links, as an example, and introduces the solution provided in this application in conjunction with the stages of data acquisition, link switching, and data transmission.

[0144] The link switching method provided in this application embodiment can be applied to a drone in a dual-link adaptive switching system for drone video transmission; the following is in conjunction with... Figure 3 The working process of this system is illustrated by example:

[0145] like Figure 3 As shown, the system includes: a drone 310, a hangar 320, and a public network server 330;

[0146] The UAV 310 may include a video acquisition and processing unit ( Figure 3 (Not shown in the image), signal strength monitoring and normalization unit, link decision and handover execution unit;

[0147] The video acquisition and processing unit in UAV 310 is used for:

[0148] The GStreamer processing pipeline (i.e., the GStreamer with the first and second plugin elements built-in) pulls the H.264 (a video coding standard) video stream from the drone's pod using the RTSP protocol. Figure 3The H.264 source of the pod shown); after decoding the retrieved H.264 video stream, it is sent to the WebRTC encoder (such as the second plug-in element mentioned above) for real-time encoding, and the encoded data is encapsulated to obtain the encapsulated video stream (such as a WebRTC stream or an RTMP stream, where WebRTC stream is a video stream transmitted based on the WebRTC protocol, and RTMP stream is a video stream transmitted based on the RTMP protocol); that is, the video acquisition and processing unit can be used to implement: Figure 3 The process shown is the RTSP streaming → decoding → WebRTC encoding process performed by the GStreamer processing pipeline.

[0149] Furthermore, the UAV 310 is equipped with dual-link transmission channels: a 4G link (also known as a 4G direct transmission link) and a wireless image transmission link (also known as an image transmission relay link).

[0150] For 4G links, the transmission process may include: the drone 310 pushes the video stream directly to the public network server 330 through the 4G module (such as WebRTC stream / RTMP stream).

[0151] For the wireless video transmission link, the transmission process may include: the drone 310 sending the video stream to the hangar 320 via a dedicated video transmission module; correspondingly, the hangar 320 receives the video stream (WebRTC or RTMP stream) via a video transmission receiver, processes the video stream accordingly, and forwards it to the public network: the video stream is forwarded through an Nginx server (a high-performance open-source HTTP reverse proxy server), and finally mapped to the same public network server (i.e., the public network server used for the 4G link), that is... Figure 3 As shown, Nginx server stream forwarding and public network mapping: forwarding to the public network via image transmission relay link and uplink.

[0152] as well as,

[0153] The signal strength monitoring and normalization unit in UAV 310 is used for:

[0154] The process of collecting (e.g., real-time or periodic) reference signal received power (RSRP), signal-to-noise ratio (SNR), received signal strength indicator (RSSI), bandwidth, packet loss rate, and round-trip delay) for the 4G link; and collecting (e.g., real-time or periodic) modulation and coding scheme (MCS), bit error rate, and round-trip delay for the wireless image transmission link—in other words, the process of collecting signal strength for both the 4G module and the image transmission module; and...

[0155] Based on the collected parameter values, the signal strength evaluation value S_4G of the 4G link and the signal strength evaluation value S_VT of the wireless image transmission link are calculated in accordance with the method described in the above embodiments. The signal strength of the two communication links is then normalized to the same evaluation value range to obtain the normalized results S_4G and S_VT.

[0156] The link decision and switching execution unit in UAV 310 is used for:

[0157] Compare the normalized S_4G and S_VT;

[0158] If the current communication link is a wireless image transmission link, and S_4G>S_VT and S_4G / S_VT is greater than 1.2, then the target switching conditions required to switch from the wireless image transmission link to the 4G link are met. The drone is then controlled to switch to the 4G link by issuing a switching control command (i.e., the switching command mentioned above); otherwise, the wireless image transmission link is maintained.

[0159] If the current communication link is a 4G link, and S_VT > S_4G, then the switching conditions required to switch from the 4G link to the wireless image transmission link are met. The drone is then controlled to switch to the wireless image transmission link by issuing a switching control command (i.e., the switching command mentioned above). Otherwise, the 4G link is maintained.

[0160] Specifically, during the process of controlling the drone to switch links, the switching control command is sent from the drone's link decision and switching execution unit to the WebRTC streaming media P2P module (also known as the WebRTC P2P module, which is the module located in the second plugin element. Specifically, it refers to an end-to-end connection engine that can automatically penetrate NAT, negotiate media, and encrypt transmission, allowing the browser / device to transmit real-time streams as if in a "direct conversation," and is the core of WebRTC's low latency).

[0161] Furthermore, when transmitting video streams via the communication link, the P2P module can use UDP (User Datagram Protocol) for stateless transmission (i.e., it does not maintain connection state or wait for the receiving end to acknowledge the transmission of video streams, but directly sends data packets in real time, thereby reducing transmission latency and meeting the needs of real-time audio and video communication). Moreover, by optimizing the P2P transmission method (i.e., sending according to predetermined switching rules), when the switching control command is issued to the P2P module, the new link and the original link simultaneously send a certain duration of video data (e.g., 2 seconds of video data). Then the new link continues to send data, and the original link is disconnected. Here, there will be a certain duration of data overlap between the original link and the new link (e.g., 2 seconds). During this switching, the playback end will be unaware of the process.

[0162] as well as,

[0163] Public server 330 is used for:

[0164] In the event of a link switch, the system provides video streaming services, including aggregation, recording, and distribution. In other words, it receives and aggregates video streams from both links, provides a unified WebRTC / RTMP streaming interface, and records link switch logs and signal quality data for later analysis and optimization.

[0165] To further understand the solution, in conjunction with Figure 4 This section describes the signal strength assessment and handover decision-making process in this link handover method:

[0166] like Figure 4 As shown, the signal strength assessment and handover decision-making process may include:

[0167] S401: Determine if the monitoring cycle has been reached. If yes, trigger S403; otherwise, only execute S402.

[0168] In this case, S402 can continue to be executed while S403 is being triggered.

[0169] S402 controls the continuous transmission of the video stream; that is, based on the currently used communication link (video transmission relay link), the video stream is continuously transmitted.

[0170] S403, Real-time signal monitoring;

[0171] Specifically, for 4G links, 4G parameters are collected: RSSI, SNR, and packet loss rate; for image transmission relay links, image transmission parameters are collected: MCS, bit error rate, and round-trip delay.

[0172] S404, signal strength normalization;

[0173] Based on the collected parameters, signal strength assessment values ​​are calculated for both 4G links and image transmission relay links. Specifically, for 4G links, a weighted calculation is performed based on 4G parameters (i.e.,...). Figure 4 The 4G parameter weighting calculation in the image transmission relay link is performed based on the image transmission parameters (i.e., weighting calculation). Figure 4 The image transmission parameters are weighted and calculated to map to one of the levels from 0 to 4 (i.e., Figure 4 The mapping in the model is from 0 to 4, and the final output is S_4G, and the output is S_VT.

[0174] S405, make a decision to determine whether S_4G>S_VT and whether the ratio is greater than a predetermined threshold. If yes, trigger S406; otherwise, trigger S407.

[0175] This ratio is obtained by dividing S_4G by S_VT.

[0176] S406 selects the 4G direct transmission link as the main push stream channel;

[0177] In the case where the image transmission relay link is the currently used communication link, if S405 is met, the 4G direct transmission link is selected as the main push channel, and it is necessary to switch from the image transmission relay link to the 4G direct transmission link through S408.

[0178] S407, select the image transmission relay link as the main push stream channel;

[0179] If the image transmission relay link is the currently used communication link and does not meet S405, then the image transmission relay link is selected as the main push channel, and video stream transmission continues to be carried out through the image transmission relay link.

[0180] S408, Execute switch: Control GStreamer to process pipeline output routing;

[0181] The so-called output routing refers to the switching control of communication links.

[0182] To better understand the video data processing process, combined with Figure 5 To introduce it. For example... Figure 5 As shown, the following processes can be performed sequentially through the GStreamer processing pipeline:

[0183] Pulling streams from pods (e.g., pulling H.264 video streams from a drone's pod using the RTSP protocol).

[0184] The data obtained from the pull stream is decoded to obtain the original video frames (also known as RAW Video). For example, it can be decoded using an H.264 Decoder to obtain the original video frames.

[0185] The data is re-encoded based on the WebRTC protocol and then encapsulated to obtain a video stream for transmission. For example, it is re-encoded based on the WebRTC Video Encoder and then encapsulated through the WebRTC transport (i.e., the transport layer / WebRTC transport channel based on the WebRTC protocol).

[0186] The link decision and switching execution unit can send switching control commands (i.e., switching commands) to the link switcher (such as the P2P module mentioned above). Thus, the link switcher (such as the P2P module mentioned above) is controlled by the link decision and switching execution unit to perform link switching, so as to send the video stream to the 4G module (also known as 4G Sender) or to the image transmission module (also known as VT Sender), that is, to the processing module corresponding to the communication link after the link switching, so as to finally transmit it to the public network server.

[0187] The solution provided in this specific embodiment proposes a dual-link signal strength normalization model to unify heterogeneous link indicators to a comparable range (0-4); it designs a hot-switching mechanism based on real-time strength comparison to avoid frequent switching caused by fixed thresholds, achieving highly reliable and low-latency UAV video transmission with a smooth and imperceptible switching process; it adopts the GStreamer+WebRTC standardized framework to achieve decoupling of encoding / decoding, transmission, and control, resulting in strong compatibility and good scalability; it constructs a hangar as an intelligent relay node, supporting integrated local storage, edge analysis, and forwarding, as well as remote deployment and edge computing expansion; and it achieves full public network accessibility, supporting remote monitoring and command across regions and network environments.

[0188] The solution provided in this specific embodiment can have the following beneficial effects:

[0189] Transmission reliability is greatly improved: the dual links serve as backups for each other, and the optimal path is automatically selected based on signal quality, effectively avoiding single points of failure;

[0190] Smooth and seamless switching: The decision-making mechanism based on real-time signal strength comparison, combined with WebRTC's NACK (Negative Acknowledgment) and FEC (Forward Error Correction) anti-packet loss mechanisms, ensures continuous and uninterrupted video during switching.

[0191] Adapting to complex environments: In areas with weak 4G signals but stable image transmission (such as remote mountainous areas), prioritize the use of wireless image transmission links; in areas with strong 4G signals but interference with wireless image transmission links (such as urban areas), prioritize the use of 4G links to improve overall coverage.

[0192] Flexible deployment and easy expansion: The hangar can serve as an edge computing node, supporting local AI (Artificial Intelligence) analysis, storage and playback, and other functions; unified access to public network servers facilitates the management of multiple drones;

[0193] Strong standardization and compatibility: Adopting mainstream protocols such as RTSP and WebRTC, it can be adapted to various pods, 4G modules and image transmission equipment, reducing integration costs.

[0194] Corresponding to the above method embodiments, this application also provides a link switching device, such as... Figure 6 As shown, the link switching device may include:

[0195] The parameter acquisition module 610 is used to acquire the parameter values ​​of each communication link of the UAV; wherein each communication link includes the first communication link currently used in the video data transmission process and at least one second communication link that is not currently in use;

[0196] The evaluation value determination module 620 is used to evaluate and analyze each communication link based on the acquired parameter values ​​to obtain a signal strength evaluation value; wherein, the evaluation and analysis includes performing an initial evaluation according to parameter values ​​of different parameter types, and fusing the evaluation values ​​obtained from the initial evaluation to obtain a signal strength evaluation value;

[0197] The link determination module 630 is used to determine the second communication link to be switched to based on the determined signal strength evaluation value;

[0198] The first control module 640 is used to control the first communication link and the determined second communication link to transmit video data simultaneously; wherein, the video data transmitted when the determined second communication link is activated is the same as that transmitted when the second communication link is activated.

[0199] The second control module 650 is used to shut down the first communication link if the determined second communication link has been transmitting for a preset time.

[0200] Optionally, the link determination module is specifically used for:

[0201] Based on the determined signal strength evaluation value, select a second communication link that meets the target handover conditions as the second communication link to be handed over to;

[0202] The conditions for the target switching include:

[0203] The signal strength assessment value is greater than that of the first communication link and the switchable auxiliary condition is met;

[0204] or,

[0205] When the anti-interference capability of the first communication link is not higher than that of the second communication link, the conditions for the target switching include:

[0206] The signal strength assessment value is greater than that of the first communication link.

[0207] Optionally, the determination method for the second communication link to satisfy the switchable auxiliary conditions includes:

[0208] The first evaluation index corresponding to the second communication link is greater than the preset first index threshold; wherein, the first evaluation index corresponding to the second communication link represents the difference between the signal strength evaluation value of the second communication link and the signal strength evaluation value of the first communication link;

[0209] or,

[0210] The target parameter value of the second communication link is greater than the target parameter value of the first communication link, and the second evaluation index is greater than the preset second index threshold; wherein, the target parameter value of the second communication link and the target parameter value of the first communication link are both parameter values ​​characterizing the link network environment, and the second evaluation index characterizes the difference between the target parameter value of the second communication link and the target parameter value of the first communication link.

[0211] Optionally, the parameter values ​​of each communication link include: at least one primary parameter value and at least one secondary parameter value; the primary parameter values ​​are different for different communication links;

[0212] The evaluation value determination module includes:

[0213] The first determining unit is configured to determine a first evaluation value for each of the communication links based on the acquired at least one main parameter value and the evaluation method set for the at least one main parameter value.

[0214] The second determining unit is used to determine at least one second evaluation value for each communication link based on the acquired at least one auxiliary parameter value and according to the evaluation method set for each auxiliary parameter value.

[0215] The third determining unit is used to calculate the signal strength evaluation value of each of the communication links based on the determined first evaluation value and second evaluation value.

[0216] Optionally, the first determining unit is specifically used for:

[0217] For each of the communication links, if the at least one main parameter value of the communication link satisfies the corresponding value condition, then the maximum value within the range of evaluation values ​​is selected as the first evaluation value of the communication link.

[0218] If any of the at least one main parameter values ​​of the communication link does not meet the corresponding value selection condition, then the minimum value within the range of the evaluation value is selected as the first evaluation value of the communication link; wherein, the value selection condition corresponding to each main parameter value is to characterize that the signal strength meets the preset reliability strength range.

[0219] Optionally, the second determining unit is used to:

[0220] Obtain the target mapping relationship corresponding to each auxiliary parameter value of each of the communication links; wherein, the target mapping relationship corresponding to each auxiliary parameter value is: a mapping relationship representing the auxiliary parameter value and the evaluation value in the range of the evaluation value;

[0221] Based on the obtained target mapping relationship, each auxiliary parameter value of each communication link is mapped to the range of the evaluation value to obtain at least one second evaluation value for each communication link.

[0222] Optionally, the third determining unit is used to:

[0223] Determine a weighted calculation method that matches the range of the evaluation value; wherein the weighted calculation method is used to ensure that the value obtained by the weighted calculation is within the range of the evaluation value;

[0224] Based on the weighted calculation method, the determined first evaluation value and second evaluation value are weighted to obtain the signal strength evaluation value of each communication link; wherein the signal strength evaluation value is within the range of the evaluation value.

[0225] Optionally, each communication link includes a wireless image transmission link and a cellular network-based communication link;

[0226] The at least one primary parameter value of the wireless image transmission link includes: modulation and coding strategy; correspondingly, the at least one secondary parameter value of the wireless image transmission link includes: bit error rate and / or round-trip delay.

[0227] The at least one primary parameter value of the cellular network-based communication link includes: reference signal received power and / or signal-to-noise ratio; correspondingly, the at least one secondary parameter value of the cellular network-based communication link includes one or more of: received signal strength indication, bandwidth, packet loss rate, and round-trip delay.

[0228] Optionally, the video data transmission process includes:

[0229] Based on the first plugin element in the multimedia processing framework GStreamer, the video data collected by the drone is obtained.

[0230] The video data is decoded to obtain decoded data;

[0231] The decoded data is transmitted to a second plugin element in the GStreamer; wherein the second plugin element is used to encode and encapsulate the decoded data.

[0232] Control the transmission of encapsulated video data through the current communication link.

[0233] Corresponding to the above method embodiments, this invention also provides an electronic device, such as... Figure 7 As shown, it includes a processor 701, a communication interface 702, a memory 703, and a communication bus 704, wherein the processor 701, the communication interface 702, and the memory 703 communicate with each other through the communication bus 704.

[0234] Memory 703 is used to store computer programs;

[0235] When the processor 701 executes the program stored in the memory 703, it implements the steps of any link switching method provided in the embodiments of this application.

[0236] The communication bus mentioned in the above electronic devices can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. This communication bus can be divided into address bus, data bus, control bus, etc. For ease of illustration, only one thick line is used to represent it in the diagram, but this does not mean that there is only one bus or one type of bus.

[0237] The communication interface is used for communication between the aforementioned electronic devices and other devices.

[0238] The memory may include random access memory (RAM) or non-volatile memory (NVM), such as at least one disk storage device. Optionally, the memory may also be at least one storage device located remotely from the aforementioned processor.

[0239] The processors mentioned above can be general-purpose processors, including central processing units (CPUs), network processors (NPs), etc.; they can also be digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0240] In another embodiment of the present invention, an aircraft is also provided, including an aircraft body and a controller. The controller is disposed on the aircraft body and is used to execute the above-described link switching method.

[0241] In another embodiment of the present invention, a computer-readable storage medium is also provided, which stores a computer program that, when executed by a processor, implements the steps of any of the above-described link switching methods.

[0242] In another embodiment of the present invention, a computer program product containing instructions is also provided, which, when run on a computer, causes the computer to execute any of the link switching methods described above.

[0243] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid-state disk (SSD)).

[0244] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0245] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for embodiments such as apparatus and devices, since they are basically similar to the method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0246] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A link switching method, characterized in that, include: The parameter values ​​of each communication link of the UAV are periodically acquired; wherein each communication link includes a first communication link currently used in the video data transmission process and at least one second communication link that is not currently in use, and each communication link includes a wireless image transmission link and a cellular network-based communication link; Based on the obtained parameter values, each communication link is evaluated and analyzed to obtain a signal strength evaluation value; Based on the determined signal strength assessment value, determine the second communication link to which to switch; The system controls the first communication link and the determined second communication link to transmit video data simultaneously; wherein, when the determined second communication link is activated, the video data transmitted is the same as that transmitted through the first communication link. If the determined second communication link has been transmitting continuously for a preset time, then the first communication link is closed; The parameter values ​​of each communication link include: at least one primary parameter value and at least one secondary parameter value; the primary parameter values ​​are different for different communication links. Based on the acquired parameter values, each communication link is evaluated and analyzed to obtain a signal strength evaluation value, including: For each of the communication links, if the at least one main parameter value of the communication link satisfies the corresponding value condition, then the maximum value within the range of evaluation values ​​is selected as the first evaluation value of the communication link; if there is a main parameter value among the at least one main parameter value of the communication link that does not satisfy the corresponding value condition, then the minimum value within the range of evaluation values ​​is selected as the first evaluation value of the communication link; wherein, the value condition corresponding to each main parameter value is to characterize that the signal strength satisfies a preset reliability strength range; Based on the acquired at least one auxiliary parameter value, at least one second evaluation value is determined for each of the communication links according to the evaluation method set for each auxiliary parameter value. Based on the determined first and second evaluation values, a signal strength evaluation value is calculated for each of the communication links.

2. The method according to claim 1, characterized in that, The step of determining the second communication link to be switched to based on the determined signal strength evaluation value includes: Based on the determined signal strength evaluation value, select a second communication link that meets the target handover conditions as the second communication link to be handed over to; The conditions for the target switching include: The signal strength assessment value is greater than that of the first communication link and the switchable auxiliary condition is met; or, When the anti-interference capability of the first communication link is not higher than that of the second communication link, the conditions for the target switching include: The signal strength assessment value is greater than that of the first communication link.

3. The method according to claim 2, characterized in that, The methods for determining whether the second communication link meets the switchable auxiliary conditions include: The first evaluation index corresponding to the second communication link is greater than the preset first index threshold; wherein, the first evaluation index corresponding to the second communication link represents the difference between the signal strength evaluation value of the second communication link and the signal strength evaluation value of the first communication link; or, The target parameter value of the second communication link is greater than the target parameter value of the first communication link, and the second evaluation index is greater than the preset second index threshold; wherein, the target parameter value of the second communication link and the target parameter value of the first communication link are both parameter values ​​characterizing the link network environment, and the second evaluation index characterizes the difference between the target parameter value of the second communication link and the target parameter value of the first communication link.

4. The method according to claim 1, characterized in that, The step of determining at least one second evaluation value for each communication link based on the acquired at least one auxiliary parameter value and according to the evaluation method set for each auxiliary parameter value includes: Obtain the target mapping relationship corresponding to each auxiliary parameter value of each of the communication links; wherein, the target mapping relationship corresponding to each auxiliary parameter value is: a mapping relationship representing the auxiliary parameter value and the evaluation value in the range of the evaluation value; Based on the obtained target mapping relationship, each auxiliary parameter value of each communication link is mapped to the range of the evaluation value to obtain at least one second evaluation value for each communication link.

5. The method according to claim 1, characterized in that, The calculation of the signal strength evaluation value for each communication link based on the determined first and second evaluation values ​​includes: Determine a weighted calculation method that matches the range of the evaluation value; wherein the weighted calculation method is used to ensure that the value obtained by the weighted calculation is within the range of the evaluation value; Based on the weighted calculation method, the determined first evaluation value and second evaluation value are weighted to obtain the signal strength evaluation value of each communication link; wherein the signal strength evaluation value is within the range of the evaluation value.

6. The method according to claim 1, characterized in that, The at least one primary parameter value of the wireless image transmission link includes: modulation and coding strategy; correspondingly, the at least one secondary parameter value of the wireless image transmission link includes: bit error rate and / or round-trip delay. The at least one primary parameter value of the cellular network-based communication link includes: reference signal received power and / or signal-to-noise ratio; correspondingly, the at least one secondary parameter value of the cellular network-based communication link includes one or more of: received signal strength indication, bandwidth, packet loss rate, and round-trip delay.

7. The method according to any one of claims 1-3, characterized in that, The video data transmission process includes: Based on the first plugin element in the multimedia processing framework GStreamer, the video data collected by the drone is obtained. The video data is decoded to obtain decoded data; The decoded data is transmitted to a second plugin element in the GStreamer; wherein the second plugin element is used to encode and encapsulate the decoded data. Control the transmission of encapsulated video data through the current communication link.

8. A link switching device, characterized in that, include: The parameter acquisition module is used to periodically acquire the parameter values ​​of each communication link of the UAV; wherein each communication link includes a first communication link currently used in the video data transmission process and at least one second communication link that is not currently in use, and each communication link includes a wireless image transmission link and a cellular network-based communication link; The evaluation value determination module is used to evaluate and analyze each communication link based on the acquired parameter values ​​to obtain the signal strength evaluation value; The link determination module is used to determine the second communication link to which to switch based on the determined signal strength evaluation value; The first control module is used to control the first communication link and the determined second communication link to transmit video data simultaneously; wherein, the video data transmitted when the determined second communication link is activated is the same as that transmitted when the second communication link is activated. The second control module is used to shut down the first communication link if the determined second communication link has been transmitting continuously for a preset time. The parameter values ​​of each communication link include: at least one primary parameter value and at least one secondary parameter value; the primary parameter values ​​are different for different communication links. Based on the acquired parameter values, each communication link is evaluated and analyzed to obtain a signal strength evaluation value, including: For each of the communication links, if the at least one main parameter value of the communication link satisfies the corresponding value condition, then the maximum value within the range of evaluation values ​​is selected as the first evaluation value of the communication link; if there is a main parameter value among the at least one main parameter value of the communication link that does not satisfy the corresponding value condition, then the minimum value within the range of evaluation values ​​is selected as the first evaluation value of the communication link; wherein, the value condition corresponding to each main parameter value is to characterize that the signal strength satisfies a preset reliability strength range; Based on the acquired at least one auxiliary parameter value, at least one second evaluation value is determined for each of the communication links according to the evaluation method set for each auxiliary parameter value. Based on the determined first and second evaluation values, a signal strength evaluation value is calculated for each of the communication links.

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