As smart city construction and low-altitude airspace development accelerate globally, urban airspace digitalization has become a key infrastructure focus. From uncoordinated drone flights to precise low-altitude traffic management, the low altitude digital twin (LADT) serves as the core platform for digital airspace management. Its development relies heavily on radar airspace sensing technologies. Millimeter-wave radar, with its high precision, all-weather capability, and real-time responsiveness, bridges physical low-altitude airspace and digital twin systems, advancing cities worldwide from a “can fly” stage to a “schedulable” stage, providing robust technical support for flight service providers and urban digital planners.
Technical Foundation: Millimeter-Wave Radar as the Core of Radar Airspace Sensing
The essence of low-altitude digital twins is to replicate physical airspace with high fidelity in real time. Millimeter-wave radar addresses the limitations of traditional sensing methods in complex urban environments, serving as the “digital eye” for LADTs worldwide.
4D Full-Dimensional Sensing for Centimeter-Level Airspace Mapping
Traditional 3D radar captures distance, speed, and horizontal angle. 4D millimeter-wave radar adds vertical height measurement, enabling four-dimensional data collection: speed, distance, horizontal angle, and vertical height. With angular resolution up to 0.5° and effective detection range exceeding 150 meters, it precisely tracks drones, eVTOLs, and static obstacles such as buildings, bridges, and power lines.
Global deployments in Europe, North America, and Asia demonstrate the technology’s capacity for real-time monitoring and trajectory prediction in urban airspace, supporting advanced LADT modeling.
All-Weather Capability for Continuous Airspace Awareness
Urban low-altitude airspace often faces weather changes, lighting variations, building obstructions, and electromagnetic interference. Millimeter-wave radar can operate reliably in rain, snow, fog, or low-light conditions, and penetrate certain dielectric materials. AI-assisted processing reduces false detection rates, ensuring continuous airspace awareness for LADTs and supporting safe, reliable, all-weather operations.
From “Can Fly” to “Schedulable”: Digital Airspace Intelligence
Early-stage low-altitude operations focus on safe flight. Advanced stages require intelligent airspace resource scheduling. Millimeter-wave radar enables LADTs to evolve from static replication to dynamic decision-making, forming the core of global digital airspace intelligence.
Real-Time Data Capture for Synchronized Airspace Replication
With refresh rates of 50–500 Hz and centimeter-level accuracy, millimeter-wave radar provides millisecond-level updates on low-altitude targets. In logistics, urban air mobility, and emergency response scenarios, radar captures position, speed, and surrounding obstacles of aerial vehicles, allowing LADTs to dynamically adjust flight paths and reduce collision risk.
Dynamic Trajectory Prediction for Intelligent Scheduling
AI-driven signal processing enables millimeter-wave radar to predict flight trajectories, providing early warnings of potential conflicts. International standards and regulations increasingly require autonomous obstacle avoidance for drones. Radar-based trajectory prediction supplies LADT scheduling modules with actionable data. For example, trials in the Yangtze River Delta and European smart airspace initiatives reduced drone flight approval times from hours to seconds, dramatically improving airspace management efficiency.
Multi-Source Data Integration for a Global LADT Ecosystem
Millimeter-wave radar can integrate with 5G-A, GNSS/Beidou, ADS-B, and other sensing technologies to form heterogeneous perception architectures. Low-latency communication ensures radar data is synchronized to city-level or cross-regional LADT platforms, supporting coordinated scheduling and making radar airspace sensing a core element of the global digital twin ecosystem.
Global Applications: Enabling Service Providers and Urban Planners
Empowering Low-Altitude Flight Service Providers
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Intelligent Drone Management: Real-time monitoring and trajectory prediction enable autonomous obstacle avoidance and path optimization, improving efficiency in logistics and urban air mobility.
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Operational Optimization: LADTs allow operators to simulate airspace and plan flight paths and contingency scenarios, supporting safe and efficient operations.
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Value-Added Services: Accumulated airspace traffic data can enable dynamic airspace resource allocation and other innovative service models.
Supporting Urban Digital Twin Construction
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Integrated Air-Ground-Space Awareness: Radar networks fill the low-altitude gap in traditional urban digital twins, enabling unified monitoring of aerial vehicles.
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Standardized Infrastructure Deployment: Global pilot projects demonstrate that radar combined with intelligent scheduling terminals enables unattended, automated operations, improving site utilization and airspace management efficiency.
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Regulatory Compliance: Radar data supports the standardization of urban low-altitude management, aligning with international smart city airspace regulations.
Future Outlook: Towards a Globally Connected Low-Altitude Digital Twin
With the expansion of global low-altitude communication and navigation networks, smart airspace management systems, and unmanned aerial vehicle applications, millimeter-wave radar will integrate deeply with cloud computing and AI. This will enable LADTs to achieve full-domain awareness, real-time mapping, and intelligent scheduling. Over the next decade, high-performance millimeter-wave radar-equipped drones are expected to become increasingly prevalent, forming a technological backbone for the global low-altitude economy.
From “can fly” to “schedulable,” millimeter-wave radar enables precise digital control of low-altitude airspace, forming the core support for LADTs worldwide. Cities and operators are poised to leverage this technological evolution, integrating physical airspace with digital twins to enable safe, efficient, and scalable low-altitude operations.
FAQ (Global Perspective)
Q1: What is a low-altitude digital twin (LADT)?
A1: LADT is a real-time, high-fidelity digital representation of urban low-altitude airspace, used for drone and eVTOL traffic management.
Q2: What role does millimeter-wave radar play in LADTs?
A2: It provides centimeter-level accuracy and all-weather sensing, capturing aerial vehicle trajectories and obstacles to support real-time synchronization and trajectory prediction.
Q3: How does millimeter-wave radar compare to traditional sensors?
A3: It offers all-weather, high-precision, real-time capabilities and can integrate with AI for enhanced perception and predictive control, suitable for complex urban environments globally.
Q4: How do LADTs integrate with other technologies?
A4: They can be combined with 5G-A, GNSS/Beidou, ADS-B, and other systems to enable cross-regional coordination and multi-source data fusion.