군사 시뮬레이션 및 훈련 시장 보고서 : 동향, 예측, 경쟁 분석(-2035년)

The future of the global military simulation and training market looks promising with opportunities in the air force, army, and navy markets. The global military simulation and training market is expected to reach an estimated $22 billion by 2035 with a CAGR of 5.1% from 2026 to 2035. The major drivers for this market are the increasing need for realistic combat training, the rising adoption of virtual training platforms, and the growing demand for cost-effective simulation solutions.

• Lucintel forecasts that, within the type category, software is expected to witness higher growth over the forecast period.
• Within the application category, air force is expected to witness the highest growth.
• In terms of region, APAC is expected to witness the highest growth over the forecast period.

Emerging Trends in the Military Simulation and Training Market

The military simulation and training market is experiencing rapid evolution driven by technological advancements, changing defense strategies, and increasing demand for cost-effective, realistic training solutions. As nations seek to enhance their military preparedness while minimizing risks and expenses, innovative simulation technologies are becoming integral to defense programs worldwide. These developments are not only transforming traditional training methods but also expanding the scope and capabilities of military simulations. The following key trends highlight the major shifts shaping this dynamic market, reflecting its trajectory towards more sophisticated, integrated, and versatile training systems.

• Integration of Artificial Intelligence: AI is increasingly embedded in military simulations to create more realistic and adaptive training environments. AI-driven scenarios can respond dynamically to trainee actions, providing personalized feedback and enhancing decision-making skills. This integration allows for complex, unpredictable situations that better prepare personnel for real-world challenges. AI also facilitates automation of routine training tasks, reducing costs and increasing efficiency. As AI technology advances, its role in creating immersive, intelligent simulations will expand, making training more effective and engaging.
• Adoption of Virtual Reality and Augmented Reality: VR and AR technologies are revolutionizing military training by offering immersive, interactive experiences. VR provides fully simulated environments where soldiers can practice tactics without physical risks, while AR overlays digital information onto real-world settings for enhanced situational awareness. These technologies improve engagement, retention, and realism of training exercises. They also enable remote training and collaboration across different locations, reducing logistical costs. As hardware becomes more affordable and sophisticated, VR and AR are set to become standard tools in military education and readiness programs.
• Emphasis on Cost-Effective and Scalable Solutions: Budget constraints and the need for widespread training have driven the market toward scalable simulation systems that deliver high-quality training at lower costs. Modular and cloud-based platforms allow for flexible deployment across various units and locations. These solutions reduce the need for expensive live exercises and physical equipment, making training more accessible and frequent. The focus on cost-effectiveness also encourages innovation in software development, leading to more customizable and adaptable training modules that meet diverse operational needs.
• Increased Use of Networked and Live Virtual-Constructive Environments: The integration of live, virtual, and constructive simulations creates comprehensive, networked training ecosystems. These environments enable multiple units and platforms to train together in synchronized scenarios, enhancing interoperability and coordination. LVC systems support large-scale exercises that mimic real operational conditions, providing valuable insights into combat readiness. The connectivity and scalability of these environments facilitate joint training across different branches and allied forces, fostering stronger collaboration and strategic alignment in complex mission scenarios.
• Focus on Cyber and Electronic Warfare Training: As cyber threats and electronic warfare become central to modern military operations, specialized simulation training is gaining prominence. These programs prepare personnel to defend against cyber-attacks, conduct electronic warfare, and operate advanced communication systems. Simulations replicate cyber attack scenarios and electronic countermeasures, allowing trainees to develop critical skills in a controlled environment. This trend reflects the increasing importance of cyber resilience and electronic warfare capabilities in national defense strategies, ensuring forces are prepared for contemporary digital battlefield challenges.

These emerging trends are fundamentally reshaping the military simulation and training market by making training more realistic, accessible, and technologically advanced. They are enabling militaries worldwide to enhance readiness, improve operational efficiency, and adapt to evolving threats, ultimately leading to more effective defense capabilities in an increasingly complex global security landscape.

Recent Developments in the Military Simulation and Training Market

The military simulation and training market is experiencing rapid growth driven by technological advancements, increasing defense budgets, and the need for cost-effective training solutions. Governments worldwide are investing heavily in simulation technologies to enhance readiness and reduce operational risks. The integration of virtual reality, augmented reality, and artificial intelligence is transforming traditional training methods. These developments are creating new opportunities for defense contractors and technology providers, shaping the future landscape of military preparedness and strategic capabilities.

• Growing Adoption of Virtual Reality: The integration of VR in military training offers immersive, realistic scenarios that improve skill acquisition and decision-making. VR reduces training costs and risks associated with live exercises, enabling repeated practice in safe environments. This technology enhances engagement and retention among trainees, leading to better preparedness. As VR hardware becomes more affordable and sophisticated, its adoption is expected to accelerate, significantly impacting training efficiency and effectiveness.
• Increased Use of Artificial Intelligence: AI-driven simulations enable dynamic, adaptive training environments that respond to trainee actions in real-time. AI enhances scenario complexity and realism, providing personalized feedback and performance analysis. This technology reduces the need for extensive human instructors and allows for scalable training programs. The deployment of AI in military simulations is improving strategic decision-making and operational readiness, making training more efficient and tailored to evolving threats.
• Expansion of Networked and Distributed Simulations: The development of networked simulation systems allows multiple units to train simultaneously across different locations, fostering joint operations and interoperability. These distributed simulations support complex, large-scale exercises without logistical constraints. They enable real-time communication and coordination, crucial for modern warfare. This approach reduces costs and enhances the realism of multi-domain training, significantly impacting military preparedness and strategic collaboration.
• Rising Demand for Cost-Effective Training Solutions: Budget constraints and the need for efficient resource utilization are driving demand for simulation-based training. Virtual and augmented reality solutions offer scalable, repeatable, and safe training environments that reduce reliance on expensive live exercises. These solutions enable continuous training and skill maintenance, even in resource-limited settings. The focus on cost-effectiveness is encouraging innovation and adoption of advanced simulation technologies across defense sectors worldwide.
• Integration of Augmented Reality for Field Training: AR enhances real-world training by overlaying digital information onto physical environments, providing contextual and situational awareness. It allows soldiers to practice complex procedures and tactics in realistic settings with immediate feedback. AR applications improve training speed and accuracy, especially in field operations and maintenance tasks. As AR technology becomes more portable and user-friendly, its integration into military training is expected to grow, improving operational readiness and tactical proficiency.

These developments are revolutionizing the military simulation and training market by making training more immersive, cost-effective, and scalable. The adoption of VR, AI, networked simulations, and AR is enhancing strategic capabilities and operational readiness. As technology continues to evolve, the market is poised for significant growth, offering innovative solutions that improve training outcomes and reduce costs. These advancements are shaping the future of military preparedness globally.

Strategic Growth Opportunities in the Military Simulation and Training Market

The military simulation and training market is experiencing rapid growth driven by technological advancements, increasing defense budgets, and the need for cost-effective, realistic training solutions. As nations seek to enhance operational readiness and reduce risks, innovative simulation technologies are becoming integral to military preparedness. The market presents significant opportunities for vendors to develop advanced, immersive training systems that improve skill acquisition, operational efficiency, and strategic capabilities across various defense sectors worldwide.

• Enhanced Realism Through Immersive Technologies: The integration of virtual reality (VR), augmented reality (AR), and mixed reality (MR) is revolutionizing military training by providing highly realistic, immersive environments. These technologies enable soldiers to experience complex combat scenarios without physical risks, improving decision-making, coordination, and response times. As hardware becomes more affordable and software more sophisticated, demand for such advanced simulation systems is expected to surge, offering significant growth opportunities for industry players.
• Increasing Adoption of Network-Centric and Joint Training Solutions: Modern military operations rely heavily on network-centric warfare, requiring joint training across different branches and allied forces. The development of interoperable simulation platforms that facilitate joint exercises enhances operational cohesion and strategic planning. The market is witnessing a shift toward integrated training solutions that support multi-domain operations, creating opportunities for vendors to offer scalable, customizable systems that meet diverse military requirements and foster international collaboration.
• Rising Demand for Cost-Effective and Reusable Training Systems: Traditional live training exercises are costly, logistically complex, and sometimes limited in scope. Simulation-based training offers a cost-effective alternative by reducing the need for physical resources, personnel, and infrastructure. Reusable virtual environments allow repeated practice without additional expenses, making them attractive to defense budgets constrained by economic factors. This trend drives innovation in software development, cloud-based platforms, and modular training modules, opening avenues for market expansion.
• Growing Focus on Cyber and Electronic Warfare Training: As cyber threats and electronic warfare become central to modern conflicts, military forces are prioritizing specialized training in these domains. Simulation platforms are increasingly incorporating cyberattack scenarios, electronic countermeasures, and signal intelligence exercises. The market is expanding to include cyber warfare modules and electronic warfare simulators, providing realistic, risk-free environments for personnel to develop critical skills, thus representing a significant growth segment aligned with evolving warfare tactics.
• Expansion of Simulation Training for Special Operations and Urban Warfare: Special operations forces and urban combat scenarios demand highly specialized, adaptable training solutions. The market is witnessing growth in compact, portable simulators and scenario-based training modules tailored for these environments. These systems enable realistic training in confined, complex urban settings, enhancing tactical proficiency and safety. The increasing focus on asymmetric warfare and counter-terrorism operations fuels demand for such targeted simulation solutions, creating lucrative opportunities for vendors to innovate and customize offerings for elite units.

The overall impact of these opportunities is set to significantly enhance the capabilities, efficiency, and safety of military training programs worldwide, fostering technological innovation and strategic advantage in modern defense operations.

Military Simulation and Training Market Driver and Challenges

The military simulation and training market is influenced by a variety of technological, economic, and regulatory factors that shape its growth and development. Advances in simulation technology, increased defense budgets, and evolving training needs are key drivers. Conversely, challenges such as high implementation costs, regulatory hurdles, and technological obsolescence pose significant obstacles. Understanding these drivers and challenges is essential for stakeholders aiming to capitalize on opportunities and mitigate risks within this dynamic industry. The interplay of these factors determines the pace of innovation, market expansion, and overall competitiveness in the military simulation and training sector.

The factors responsible for driving the military simulation and training market include:

• Technological Advancements: The rapid development of virtual reality, augmented reality, and artificial intelligence has revolutionized military training. These innovations enable more realistic, immersive, and cost-effective training solutions, reducing the need for physical resources and live exercises. As technology continues to evolve, military organizations are increasingly adopting advanced simulation systems to enhance readiness and operational efficiency. This trend is expected to accelerate market growth, driven by the need for safer, scalable, and adaptable training environments that can simulate complex combat scenarios with high fidelity.
• Increasing Defense Budgets: Governments worldwide are allocating substantial funds toward modernizing their armed forces, with a focus on simulation-based training. Rising defense budgets reflect the strategic importance of preparedness and technological superiority. These investments facilitate the procurement of sophisticated simulation systems, software, and related infrastructure. As defense spending continues to grow, especially in emerging economies, the market for military simulation and training is poised for expansion, driven by the demand for cutting-edge training solutions that improve combat effectiveness and reduce operational costs.
• Geopolitical Tensions and Security Concerns: Heightened geopolitical tensions and regional conflicts have underscored the need for advanced military training. Countries are prioritizing preparedness to respond effectively to emerging threats, which fuels demand for realistic simulation environments. These scenarios allow military personnel to train for diverse combat situations without risking lives or resources. Consequently, the market benefits from increased procurement of simulation systems that support strategic readiness, interoperability, and rapid deployment capabilities, thereby reinforcing the importance of simulation-based training in modern defense strategies.
• Growing Adoption of Network-Centric Warfare: The shift toward network-centric warfare necessitates integrated training solutions that promote interoperability among various military units and platforms. Simulation systems now incorporate networked environments, enabling joint exercises and real-time data sharing. This integration enhances coordination, decision-making, and operational efficiency. As militaries worldwide adopt network-centric strategies, the demand for sophisticated, interconnected simulation platforms rises, driving market growth. The need for scalable, flexible, and secure simulation solutions that support complex, multi-domain operations is a key factor propelling this trend.

The challenges facing the military simulation and training market include:

• High Implementation and Maintenance Costs: Deploying advanced simulation systems requires significant capital investment in hardware, software, and infrastructure. Ongoing maintenance, updates, and training further add to operational expenses. These costs can be prohibitive, especially for smaller or budget-constrained defense organizations, limiting widespread adoption. The high financial barrier may slow market growth and restrict access to cutting-edge simulation technologies, thereby impacting the overall competitiveness and innovation within the industry.
• Regulatory and Certification Barriers: Stringent government regulations, export controls, and certification requirements pose hurdles for market players. Compliance with military standards and obtaining necessary approvals can be time-consuming and costly. These regulatory complexities can delay product deployment, restrict international trade, and increase development costs. Navigating diverse regulatory landscapes across countries adds to the challenge, potentially hindering market expansion and the adoption of innovative simulation solutions.
• Rapid Technological Obsolescence: The fast-paced evolution of simulation technologies creates a risk of products becoming outdated quickly. Military organizations seek the latest features and capabilities, but rapid technological changes can render existing systems obsolete, necessitating frequent upgrades or replacements. This cycle increases costs and complicates long-term planning. Companies must continuously innovate to stay competitive, which can strain resources and impact profitability, while users face challenges in maintaining up-to-date training environments.

The military simulation and training market is driven by technological innovation, increased defense spending, geopolitical tensions, and the adoption of network-centric warfare. However, high costs, regulatory hurdles, and rapid technological obsolescence present significant challenges. These factors collectively influence the pace of market growth, shaping strategic decisions for industry stakeholders. While opportunities for expansion are substantial, addressing these challenges is crucial for sustainable development and technological advancement in military simulation and training solutions.

List of Military Simulation and Training Companies

Companies in the market compete on the basis of product quality offered. Major players in this market focus on expanding their manufacturing facilities, R&D investments, infrastructural development, and leverage integration opportunities across the value chain. With these strategies military simulation and training companies cater increasing demand, ensure competitive effectiveness, develop innovative products & technologies, reduce production costs, and expand their customer base. Some of the military simulation and training companies profiled in this report include-

• Addsino
• China North Industries Group Corporation
• Nanjing Research Institute on Simulation Technique
• Huaru Technology
• VIRE Technologies
• Haige Communications Group
• Nanjing Ruichenxinchuang Network Technology
• Beijing Shenzhou Zhihui Technology
• Aviation Industry Corporation of China
• Beijing Shenzhou Huipu Technology

Military Simulation and Training Market by Segment

The study includes a forecast for the global military simulation and training market by type, application, and region.

Military Simulation and Training Market by Type [Value from 2019 to 2035]:

• Hardware
• Software

Military Simulation and Training Market by Application [Value from 2019 to 2035]:

• Air Force
• Army
• Navy

Military Simulation and Training Market by Region [Value from 2019 to 2035]:

• North America
• Europe
• Asia Pacific
• The Rest of the World

Country Wise Outlook for the Military Simulation and Training Market

The military simulation and training market has experienced significant growth driven by technological advancements, increased defense budgets, and the need for cost-effective training solutions. Countries are investing heavily in simulation technologies to enhance military readiness, reduce training costs, and improve safety. Innovations such as virtual reality, augmented reality, and artificial intelligence are transforming training methodologies. The market is also influenced by geopolitical tensions and the modernization of armed forces worldwide. As nations seek to maintain strategic advantages, the development and adoption of advanced simulation systems are accelerating, shaping the future landscape of military preparedness globally.

• United States: The United States leads in military simulation and training, with substantial investments in virtual reality and AI-driven systems. The Department of Defense has expanded its use of immersive training platforms to enhance readiness and reduce costs. Recent developments include the integration of augmented reality for combat simulations and increased collaboration with private tech firms to develop cutting-edge solutions. The U.S. military also focuses on cybersecurity training and joint multinational exercises using simulation technologies, ensuring interoperability and strategic advantage.
• China: China has rapidly advanced its military simulation capabilities, emphasizing modernization and self-reliance. The Chinese military has invested heavily in virtual and augmented reality systems for pilot and infantry training. Recent developments include the deployment of large-scale simulation centers and the integration of AI to create more realistic scenarios. China aims to develop indigenous technologies to reduce dependence on foreign systems and enhance its strategic deterrence through sophisticated simulation-based training programs.
• Germany: Germany has focused on enhancing its military simulation infrastructure to support NATO operations and national defense. Recent advancements include the adoption of networked simulation systems for joint exercises and the integration of cyber and electronic warfare training modules. Germany emphasizes interoperability with allied forces and has invested in high-fidelity simulators for land, air, and naval forces. The country also explores the use of virtual reality to improve pilot training and battlefield preparedness.
• India: India is rapidly expanding its military simulation and training capabilities to modernize its armed forces. Recent developments include the procurement of advanced simulators for aircraft, naval vessels, and ground forces. India is also investing in indigenous simulation technologies to reduce reliance on foreign systems. The focus is on creating comprehensive training ecosystems that incorporate virtual reality, AI, and networked simulations to enhance operational readiness and strategic capabilities.
• Japan: Japan has prioritized the modernization of its military simulation systems amid regional security concerns. Recent advancements include the deployment of advanced flight simulators for the Japan Self-Defense Forces and the integration of AI for tactical training. Japan is also enhancing its cyber and electronic warfare training modules through simulation platforms. The country aims to improve joint operational capabilities and ensure readiness against evolving threats in the Asia-Pacific region.

Features of the Global Military Simulation and Training Market

• Market Size Estimates: Military simulation and training market size estimation in terms of value ($B).
• Trend and Forecast Analysis: Market trends (2019 to 2025) and forecast (2026 to 2035) by various segments and regions.
• Segmentation Analysis: Military simulation and training market size by type, application, and region in terms of value ($B).
• Regional Analysis: Military simulation and training market breakdown by North America, Europe, Asia Pacific, and Rest of the World.
• Growth Opportunities: Analysis of growth opportunities in different types, applications, and regions for the military simulation and training market.
• Strategic Analysis: This includes M&A, new product development, and competitive landscape of the military simulation and training market.

Analysis of competitive intensity of the industry based on Porter's Five Forces model.

This report answers following 11 key questions:

• Q.1. What are some of the most promising, high-growth opportunities for the military simulation and training market by type (hardware and software), application (air force, army, and navy), and region (North America, Europe, Asia Pacific, and the Rest of the World)?
• Q.2. Which segments will grow at a faster pace and why?
• Q.3. Which region will grow at a faster pace and why?
• Q.4. What are the key factors affecting market dynamics? What are the key challenges and business risks in this market?
• Q.5. What are the business risks and competitive threats in this market?
• Q.6. What are the emerging trends in this market and the reasons behind them?
• Q.7. What are some of the changing demands of customers in the market?
• Q.8. What are the new developments in the market? Which companies are leading these developments?
• Q.9. Who are the major players in this market? What strategic initiatives are key players pursuing for business growth?
• Q.10. What are some of the competing products in this market and how big of a threat do they pose for loss of market share by material or product substitution?
• Q.11. What M&A activity has occurred in the last 7 years and what has its impact been on the industry?

Table of Contents

1. Executive Summary

2. Market Overview

• 2.1 Background and Classifications
• 2.2 Supply Chain

3. Market Trends & Forecast Analysis

• 3.1 Macroeconomic Trends and Forecasts
• 3.2 Industry Drivers and Challenges
• 3.3 PESTLE Analysis
• 3.4 Patent Analysis
• 3.5 Regulatory Environment

4. Global Military Simulation and Training Market by Type

• 4.1 Overview
• 4.2 Attractiveness Analysis by Type
• 4.3 Hardware : Trends and Forecast (2019-2035)
• 4.4 Software : Trends and Forecast (2019-2035)

5. Global Military Simulation and Training Market by Application

• 5.1 Overview
• 5.2 Attractiveness Analysis by Application
• 5.3 Air Force : Trends and Forecast (2019-2035)
• 5.4 Army : Trends and Forecast (2019-2035)
• 5.5 Navy : Trends and Forecast (2019-2035)

6. Regional Analysis

• 6.1 Overview
• 6.2 Global Military Simulation and Training Market by Region

7. North American Military Simulation and Training Market

• 7.1 Overview
• 7.2 North American Military Simulation and Training Market by Type
• 7.3 North American Military Simulation and Training Market by Application
• 7.4 The United States Military Simulation and Training Market
• 7.5 Canadian Military Simulation and Training Market
• 7.6 Mexican Military Simulation and Training Market

8. European Military Simulation and Training Market

• 8.1 Overview
• 8.2 European Military Simulation and Training Market by Type
• 8.3 European Military Simulation and Training Market by Application
• 8.4 German Military Simulation and Training Market
• 8.5 French Military Simulation and Training Market
• 8.6 Italian Military Simulation and Training Market
• 8.7 Spanish Military Simulation and Training Market
• 8.8 The United Kingdom Military Simulation and Training Market

9. APAC Military Simulation and Training Market

• 9.1 Overview
• 9.2 APAC Military Simulation and Training Market by Type
• 9.3 APAC Military Simulation and Training Market by Application
• 9.4 Chinese Military Simulation and Training Market
• 9.5 Indian Military Simulation and Training Market
• 9.6 Japanese Military Simulation and Training Market
• 9.7 South Korean Military Simulation and Training Market
• 9.8 Indonesian Military Simulation and Training Market

10. ROW Military Simulation and Training Market

• 10.1 Overview
• 10.2 ROW Military Simulation and Training Market by Type
• 10.3 ROW Military Simulation and Training Market by Application
• 10.4 Middle Eastern Military Simulation and Training Market
• 10.5 South American Military Simulation and Training Market
• 10.6 African Military Simulation and Training Market

11. Competitor Analysis

• 11.1 Product Portfolio Analysis
• 11.2 Operational Integration
• 11.3 Porter's Five Forces Analysis
  • Competitive Rivalry
  • Bargaining Power of Buyers
  • Bargaining Power of Suppliers
  • Threat of Substitutes
  • Threat of New Entrants
• 11.4 Market Share Analysis

12. Opportunities & Strategic Analysis

• 12.1 Value Chain Analysis
• 12.2 Growth Opportunity Analysis
  • 12.2.1 Growth Opportunity by Type
  • 12.2.2 Growth Opportunity by Application
  • 12.2.3 Growth Opportunity by Region
• 12.3 Emerging Trends in the Global Military Simulation and Training Market
• 12.4 Strategic Analysis
  • 12.4.1 New Product Development
  • 12.4.2 Certification and Licensing
  • 12.4.3 Mergers, Acquisitions, Agreements, Collaborations, and Joint Ventures

13. Company Profiles of the Leading Players Across the Value Chain

• 13.1 Competitive Analysis Overview
• 13.2 Addsino
  • Company Overview
  • Military Simulation and Training Market Business Overview
  • New Product Development
  • Merger, Acquisition, and Collaboration
  • Certification and Licensing
• 13.3 China North Industries Group Corporation
  • Company Overview
  • Military Simulation and Training Market Business Overview
  • New Product Development
  • Merger, Acquisition, and Collaboration
  • Certification and Licensing
• 13.4 Nanjing Research Institute on Simulation Technique
  • Company Overview
  • Military Simulation and Training Market Business Overview
  • New Product Development
  • Merger, Acquisition, and Collaboration
  • Certification and Licensing
• 13.5 Huaru Technology
  • Company Overview
  • Military Simulation and Training Market Business Overview
  • New Product Development
  • Merger, Acquisition, and Collaboration
  • Certification and Licensing
• 13.6 VIRE Technologies
  • Company Overview
  • Military Simulation and Training Market Business Overview
  • New Product Development
  • Merger, Acquisition, and Collaboration
  • Certification and Licensing
• 13.7 Haige Communications Group
  • Company Overview
  • Military Simulation and Training Market Business Overview
  • New Product Development
  • Merger, Acquisition, and Collaboration
  • Certification and Licensing
• 13.8 Nanjing Ruichenxinchuang Network Technology
  • Company Overview
  • Military Simulation and Training Market Business Overview
  • New Product Development
  • Merger, Acquisition, and Collaboration
  • Certification and Licensing
• 13.9 Beijing Shenzhou Zhihui Technology
  • Company Overview
  • Military Simulation and Training Market Business Overview
  • New Product Development
  • Merger, Acquisition, and Collaboration
  • Certification and Licensing
• 13.10 Aviation Industry Corporation of China
  • Company Overview
  • Military Simulation and Training Market Business Overview
  • New Product Development
  • Merger, Acquisition, and Collaboration
  • Certification and Licensing
• 13.11 Beijing Shenzhou Huipu Technology
  • Company Overview
  • Military Simulation and Training Market Business Overview
  • New Product Development
  • Merger, Acquisition, and Collaboration
  • Certification and Licensing

14. Appendix

• 14.1 List of Figures
• 14.2 List of Tables
• 14.3 Research Methodology
• 14.4 Disclaimer
• 14.5 Copyright
• 14.6 Abbreviations and Technical Units
• 14.7 About Us
• 14.8 Contact Us