[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"doc-detail-84680-en":3,"doc-seo-84680-105":29,"detail-sidebar-cat-0-en-105":90},{"code":4,"msg":5,"data":6},0,"success",{"doc_id":7,"user_id":8,"nickname":9,"user_avatar":10,"doc_module":4,"category_id":11,"category_name":12,"doc_title":13,"doc_description":14,"doc_content":15,"file_id":16,"file_url":17,"file_type":18,"file_size":19,"view_count":20,"is_deleted":4,"is_public":21,"is_downloadable":21,"audit_status":21,"page_count":11,"language":22,"language_code":23,"site_id":24,"html_lang":23,"table_of_contents":25,"faqs":26,"seo_title":13,"seo_description":14,"update_tm":27,"read_time":28},84680,4810365810221,"Aurora","https://ap-avatar.wpscdn.com/davatar_155a257f0dc6eb9ab79c44ca47cae57d",8,"Research & Report","LOTUSim Multi Domain Simulator for Marine Robotics","Simulation is critical for maritime robotics, enabling operator training, mission rehearsal, and realistic human–vehicle interaction where live testing is costly or dangerous. Existing tools mostly target autonomous behavior and often lack native human-in-the-loop interaction and realistic environmental physics. LOTUSim presents an open-source real-time, multi-user simulator coordinating aerial, surface, and underwater robotic systems, with validated scalability and strict real-time execution, plus an Ekman-inspired layered underwater current model validated against ocean reanalysis data.","LOTUSim: Multi-Domain Simulator for Marine Robotics  \nCdric Buche 1 ,3 , Juliette Grosset 1 ,2 , Hlne Lechne2 , Marie Dubromel 1 ,2 , Pierig Havez-Bodivit2 , Malcom Neo2 , Julien Prodhon2  \n1CROSSING IRL 2010, CNRS; 2Naval Group, France; 3IMT Atlantique  \narXiv :2607 .03072v 1 [ cs .MA] 3 Jul 2026  \nAbstract—Simulation is essential for maritime robotics, supporting operator training, mission rehearsal, and human–vehicle interaction in environments where real-world testing is costly or hazardous. Existing simulators focus primarily on autonomy systems and often lack human-in-the-loop interaction and realistic environmental physics. This paper introduces LOTUSim, an open-source, real-time maritime simulator supporting multi-user interaction across aerial, surface, and underwater robotic systems for coordinated naval-style operations. The first contribution of this work is enabling real-time interactive performance for users while ensuring scalability to large fleets operating within a shared interactive simulation environment. Validation demonstrates robust human-in-the-loop performance, maintaining strict real-time execution and high visual fidelity while scaling to large heterogeneous maritime drone swarms. The second contribution is a computationally efficient, Ekman-inspired layered, underwater current model that captures wind-driven, depth-dependent flow dynamics with sufficient physical fidelity for large-scale simulations. Validation against ocean reanalysis data demonstrates substantially improved accuracy compared to commonly used stochastic Gauss–Markov current models. These results confirm LOTUSim’s suitability as a simulation platform for operatorin-the-loop maritime robotics research.  \nI. INTRODUCTION  \nFor naval operations, human-in-the-loop (HITL) simulation is essential. Maritime missions are conducted under strong environmental forcing, limited sensing capabilities, and high cognitive workload, where operator decisions influence mission success and safety. Interactive simulation interfaces can significantly improve situational awareness, skill acquisition, and crew coordination by allowing operators to interact naturally with vehicles and their environment [1] .  \nDespite recent advances, existing marine robotic simulators are designed primarily for autonomous systems and sensor simulation, with limited consideration for real-time operator-centric interaction and collaborative mission execution. Even simulators actively maintained and updated in 2025, such as OceanSim [2], MarineGym [3], Stonefish [4] and HoloOcean [5], [6], do not yet provide native support for immersive, interactive operation or multi-user mission rehearsal involving human operators in the loop.  \nEnvironmental modelling represents a second major barrier to operational realism in existing marine robotic simulators. Many simulators neglect underwater currents or use simplified models: USVsim [7] relies on Computational Fluid Dynamics (CFD)-based precomputed fields, LRAUVSim [8] and MarineGym [3] uses a constant unidirectional current, and StoneFish [4] allows arbitrary profiles without physical realism. HoloOcean [6] plans to implement  \nmore realistic volumetric currents, though currently only user-defined vector fields (vortex fields) are supported. The Gauss–Markov process, implemented in UUVSim [9] and stratified in DAVE [10], provides a real-time, computationally efficient baseline. While practical, these approaches are insufficient for naval operations, where depth-dependent, wind-driven currents strongly affect vehicle behaviour, sensor performance, and operator decision-making.  \nThis paper presents LOTUSim 1 , 2 , an open-source multidomain maritime simulator (Figure 1), designed to support naval-style operations and involving both human operators and robotic systems. LOTUSim targets training, mission rehearsal in complex maritime environments, where environmental forcing, limited observability, and operator workload play a central ro","cbCairRtxlovvhuS","https://ap.wps.com/l/cbCairRtxlovvhuS","pdf",4930871,3,1,"English","en",105,"# Introduction\n## Human-in-the-loop simulation need\n## Gaps in existing marine robotic simulators\n## Environmental modeling challenges\n## LOTUSim overview and contributions\n# Review of Marine Robotic Simulators","[{\"question\":\"Why is human-in-the-loop (HITL) simulation important for maritime robotics?\",\"answer\":\"Maritime missions face strong environmental forcing, limited sensing, and high cognitive workload, and operator decisions directly affect mission success and safety. HITL simulation improves situational awareness, skill acquisition, and crew coordination through natural interaction with vehicles and environment.\"},{\"question\":\"What are the main contributions of LOTUSim?\",\"answer\":\"LOTUSim provides a framework for real-time interactive performance and scalability for large heterogeneous fleets, a high-fidelity Ekman-inspired layered underwater current model validated against ocean reanalysis data, and an integrated suite of robotic and immersive features including multiple onboard sensors and human-centric interfaces.\"},{\"question\":\"How does LOTUSim model underwater currents, and how is it validated?\",\"answer\":\"It uses a computationally efficient Ekman-inspired layered model capturing wind-driven, depth-dependent flow dynamics. Validation against ocean reanalysis data shows substantially improved accuracy versus commonly used stochastic Gauss–Markov current models.\"}]",1784197624,20,{"code":4,"msg":30,"data":31},"ok",{"site_id":24,"language":23,"slug":32,"title":13,"keywords":33,"description":14,"schema_data":34,"social_meta":85,"head_meta":87,"extra_data":89,"updated_unix":27},"lotusim-multi-domain-simulator-for-marine-robotics","",{"@graph":35,"@context":84},[36,52,67],{"@type":37,"itemListElement":38},"BreadcrumbList",[39,43,47,49],{"item":40,"name":41,"@type":42,"position":21},"https://docshare.wps.com","Home","ListItem",{"item":44,"name":45,"@type":42,"position":46},"https://docshare.wps.com/document/","Document",2,{"item":48,"name":12,"@type":42,"position":20},"https://docshare.wps.com/document/research-report/",{"item":50,"name":13,"@type":42,"position":51},"https://docshare.wps.com/document/lotusim-multi-domain-simulator-for-marine-robotics/84680/",4,{"url":50,"name":13,"@type":53,"author":54,"headline":13,"publisher":56,"fileFormat":59,"inLanguage":23,"description":14,"dateModified":60,"datePublished":61,"encodingFormat":59,"isAccessibleForFree":62,"interactionStatistic":63},"DigitalDocument",{"name":9,"@type":55},"Person",{"url":40,"name":57,"@type":58},"DocShare","Organization","application/pdf","2026-07-22","2026-07-16",true,{"@type":64,"interactionType":65,"userInteractionCount":20},"InteractionCounter",{"@type":66},"ViewAction",{"@type":68,"mainEntity":69},"FAQPage",[70,76,80],{"name":71,"@type":72,"acceptedAnswer":73},"Why is human-in-the-loop (HITL) simulation important for maritime robotics?","Question",{"text":74,"@type":75},"Maritime missions face strong environmental forcing, limited sensing, and high cognitive workload, and operator decisions directly affect mission success and safety. HITL simulation improves situational awareness, skill acquisition, and crew coordination through natural interaction with vehicles and environment.","Answer",{"name":77,"@type":72,"acceptedAnswer":78},"What are the main contributions of LOTUSim?",{"text":79,"@type":75},"LOTUSim provides a framework for real-time interactive performance and scalability for large heterogeneous fleets, a high-fidelity Ekman-inspired layered underwater current model validated against ocean reanalysis data, and an integrated suite of robotic and immersive features including multiple onboard sensors and human-centric interfaces.",{"name":81,"@type":72,"acceptedAnswer":82},"How does LOTUSim model underwater currents, and how is it validated?",{"text":83,"@type":75},"It uses a computationally efficient Ekman-inspired layered model capturing wind-driven, depth-dependent flow dynamics. 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