Research on Time Slots Aggregation and Topology Aggregation Model for Unmanned Aerial Vehicle Swarm Overall Time Synchronization

WANG Zhenling; TAO Haihong; WEI Haitao; WANG Zhengyong

doi:10.11999/JEIT251274

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WANG Zhenling, TAO Haihong, WEI Haitao, WANG Zhengyong. Research on Time Slots Aggregation and Topology Aggregation Model for Unmanned Aerial Vehicle Swarm Overall Time Synchronization[J]. Journal of Electronics & Information Technology. doi: 10.11999/JEIT251274

Citation:

WANG Zhenling, TAO Haihong, WEI Haitao, WANG Zhengyong. Research on Time Slots Aggregation and Topology Aggregation Model for Unmanned Aerial Vehicle Swarm Overall Time Synchronization[J]. Journal of Electronics & Information Technology. doi: 10.11999/JEIT251274

Citation:

WANG Zhenling, TAO Haihong, WEI Haitao, WANG Zhengyong. Research on Time Slots Aggregation and Topology Aggregation Model for Unmanned Aerial Vehicle Swarm Overall Time Synchronization[J]. Journal of Electronics & Information Technology. doi: 10.11999/JEIT251274

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Research on Time Slots Aggregation and Topology Aggregation Model for Unmanned Aerial Vehicle Swarm Overall Time Synchronization

doi: 10.11999/JEIT251274 cstr: 32379.14.JEIT251274

1.
National Key Laboratory of Radar Signal Processing, Xidian University, Xi’an 710071, China
2.
The 54th Research Institute of China Electronics Technology Group Corporation, Shijiazhuang 050081, China
3.
General Institute of China Electronics Technology Group Corporation, Beijing 100041, China

Received Date: 2025-12-01
Accepted Date: 2026-01-27
Rev Recd Date: 2026-01-27

Available Online: 2026-02-12

Abstract

Abstract

Objective Unmanned Aerial Vehicle (UAV) swarm are capable of overcoming the technical and performance constraints inherent to individual UAVs and enabling the execution of complex missions that are beyond the reach of single-platform systems. High-precision time synchronization across swarm nodes serves as a critical foundational requirement for core swarm operations, including resource scheduling, cooperative positioning, and multi-node data fusion. However, existing research on time synchronization for UAVs is predominantly confined to optimizing the accuracy of fundamental time synchronization approaches, and there are certain limitations in adapting to the topological changes during UAV swarm formation flights and achieving global synchronization among multiple nodes. As the scale of UAV swarm continues to expand, the connectivity of time comparison links between nodes during the formation flight of UAV swarm exhibits obvious time-varying characteristics, thereby posing challenges to the achievement of continuous, reliable, and precise overall time synchronization. For the scenarios of stable formation flight and formation transformation in different mission phases of UAV swarm, the Observation Time Slot Aggregation (OTSA) model and the Time-Varying Topology Aggregation (TVTA) model have been introduced for effectively enhance the robustness of global time synchronization among UAV swarm nodes and improve the Time Synchronization Accuracy (TSA) to a certain extent. This research aims to provide an effective solution for the Leader-Following Consistency Time Synchronization (LFCTS) of UAV swarm, and offer valuable references for other applications of time synchronization in heterogeneous and distributed systems. Methods Compared with the traditional Quasi Real-time Bidirectional Time Comparison (QRBTC) scheme, the time synchronization method based on OTSA model makes full use of all the synchronization signal transmission and reception link resources within every time-slot of the system synchronization period. Based on the "one transmission and multiple receptions" mechanism of all nodes, the Follower Node (FN) can achieve direct synchronization or single-hop indirect synchronization towards Leader Node (LN) in each time slot according to the OTSA model, thereby obtaining tens of times more clock skew observation samples than the traditional QRBTC scheme. The OTSA method not only enhances the robustness of global time synchronization, but also can further conduct secondary data processing through multiple time-slot synchronization samples and achieve a higher TSA than the QRBTC method. Based on the results of LFCTS for the signal synchronization period of system, the TVTA model achieves an expansion from the direct comparison and single-hop indirect comparison of the OTSA model to the cross-period multi-hop comparison, and thereby being able to solve the problem of overall time synchronization instability caused by the time-varying characteristics of the synchronization link relationship during the process of takeoff, assembly and formation transformation of the UAV swarm. Results and Discussions All of the time comparison link resources of total time-slot were fully utilized during the synchronization period in the OTSA method (Figure 2). Through the construction of the error model and simulated analysis, in the case of a UAV swarm configuration with 50 nodes and a time slot allocation of 20ms, the time synchronization based on the OTSA model can achieve a single time slot TSA of 4.10 to 4.27ns (Figure 6) and an overall TSA of 2.46 to 2.56 ns within a complete time synchronization period, which is superior to the QRBTC scheme under the same conditions (Figure 5(a)). The TVTA method fully utilizes the cross-period time synchronization comparison relationship to construct a time comparison link for multi-hop paths (Figures 3 and Figure 4). When the FN obtains the external comparison relationships of other nodes through aggregation processing, it can further utilize the one-way or two-way Dijkstra's algorithm to obtain the multi-hop comparison link with optimal connectivity, and complete the time tracing and comparison for LN through edge computing. The error calculation indicates that during the processes of takeoff, assembly, and the transition of triangle formation or rhombus formation, the time synchronization based on the TVTA model can achieve an overall TSA of better than 8.6ns, and which can provide stronger overall time synchronization capabilities. Conclusions This paper aims to address the robustness issue of time synchronization in the formation flight of UAV swarm. For the stable formation flight of UAV swarm and the formation transformation scenarios in different mission stages, the OTSA model and TVTA model were proposed, and the error model was constructed as well as the performance was analyzed. The results show that: (1) The OTSA model enhances the robustness of overall time synchronization with directly comparing and single-hop indirect comparison of multiple time slots within a time synchronization period. It can achieve an overall TSA of better than 2.5ns, which performance is outperforming the traditional QRBTC method; (2) The TVTA model achieves overall time synchronization of UAV swarm through multi-hop relay between nodes. Even when the time comparison link is subject to changes, it can still achieve a global time synchronization accuracy of better than 8.6ns. (3) These two methods fully take into account the time-varying characteristics of the comparison links between the nodes of the UAV swarm and which have been confirmed through a small-scale UAV swarm flight tests. These two methods can ensure the robustness and performance and providing necessary guarantees for the close coordination tasks of the UAV swarm. Subsequent research will further proceed with work aimed at practical flight verification, adaptation capabilities in complex scenarios, and improvement of overall accuracy.
- UAV Swarm,
- Time Synchronization,
- Time-Varying Topology Aggregation (TVTA),
- Observation Time Slots Aggregation (OTSA),
- Bidirectional Time Comparison

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References(17)

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