Space-Ground Integrated EM TwinStop leaving satellite signals "at the mercy of the sky" amid urban high-rises
Large-scale LEO constellations, direct-to-cell, NB-IoT NTN, and NR NTN are pushing the "satellite-to-ground" link into the 3GPP mainstream. But urban building blockage, low-elevation-angle shadowing, and multi-beam / multi-satellite handover make link assurance for NTN terminals a new challenge. With three product layers, MetaRadio delivers a complete toolchain spanning simulation, HIL, and EM twin for space-ground integrated scenarios.
The Real Dilemma from Satellite to Ground
"Satellite-to-ground" looks simple, but that last kilometer on the ground is the hardest
NTN link budgets are often approximated as "free space + shadow margin," yet in real deployments across cities, mountains, and indoors, multipath, penetration, shadowing, and multi-beam / multi-satellite handover make the link far more complex than the model.
Urban Building Shadowing
High-density buildings cause frequent shadow fading and multipath at low elevation angles, determining whether true "direct-to-cell" is possible.
Multi-Satellite / Multi-Beam Handover
Under LEO constellations, beam handovers are dense and inter-satellite handover latency is sensitive, easily causing dropped links and reconnection delays.
Indoor Penetration
Penetration loss models for terminals indoors, in vehicles, and aboard mass transit are highly empirical and lack deterministic prediction.
Deploying the Three Product Layers in NTN
Use ray tracing to precisely reconstruct "that last kilometer," then close the loop with HIL and twin validation
The three-layer solution covers the three stages of channel generation, terminal testing, and operations-grade EM situational awareness, making NTN business-level KPIs simulatable, testable, and continuously monitorable.
| Layer | Layer Name | Description |
|---|---|---|
| L1 | Ray Tracing / Lauraycs | Satellite trajectories + urban/mountain 3D + indoor penetration; outputs time-varying multipath and shadowing sequences for the space-ground link. |
| L2 | Virtual Drive Test / HIL | Real space-ground channels drive HIL testing and regression of NB-IoT NTN / NR NTN terminal modules. |
| L3 | EM Twin / EM-Twin | Integrates with NTN network management/scheduling to render constellation coverage, beam landing points, and terminal reachability in real time. |
End-to-End Workflow
Constellation + Ground Modeling
TLE ephemeris + multi-beam radiation patterns + urban/mountain/indoor 3D models.
Space-Ground Channel Generation
Generate time-varying CIR/PDP, Doppler, shadowing, and beam handover sequences along the trajectory.
NTN Terminal HIL
Channel emulator drives NB-IoT/NR NTN modules, regressing TTFF, handover, and packet loss.
Network Management Closed Loop
The EM twin outputs business-level coverage and reachability metrics, feeding back into scheduling strategy.
Industry-Specific Specs
| Orbit Types | LEO / MEO / GEO; supports custom ephemeris and constellation configurations |
|---|---|
| Standard Alignment | 3GPP NB-IoT NTN (Rel-17/18), NR NTN (Rel-17/18/19), ITU-R P.681 |
| Frequency Bands | L/S/C/Ku/Ka/Q/V; supports direct-to-cell (D2D) and broadband NTN |
| Multi-Beam | Configurable from tens to hundreds of beams; includes beam landing trajectories and power spectra |
| Terminal Types | Handheld terminals, IoT terminals, vehicular terminals, fixed VSAT, low-altitude/maritime terminals |
| Urban/Indoor | Includes building penetration, vehicle penetration, and indoor multipath models; calibratable against field measurements |
| Simulation Output | Link margin, reachability probability, handover risk, inter-satellite handover strategy evaluation |
| HIL Integration | Satellite channel emulator, 5G NTN gNB, terminal OTA chamber |
| Deployment | Private cloud, edge; supports integration with constellation operator network management |
Core Differentiation
Truly "end-to-end" NTN
Models both satellite trajectories and the urban/indoor ground side simultaneously, avoiding the traditional "write formulas in the sky, rely on experience on the ground."
Multi-satellite handover determinism
Repeatable evaluation and regression of beam/inter-satellite handover under LEO constellations.
Direct-to-cell simulation
Delivers deterministic conclusions on direct-to-cell link reachability under urban building shadowing.
Domestic and controllable
Forms joint HIL solutions with domestic NTN gNB and terminal module vendors.
Business-level KPIs
Beyond link margin, outputs business-level metrics such as TTFF, packet loss, and handover success rate.
Twin integration
Overlays NTN coverage onto urban/campus EM twins to form a space-ground integrated view.
Typical Scenarios
Direct-to-Cell
Coverage reachability and handover performance prediction for urban/suburban direct-to-cell.
NB-IoT NTN
Coverage and uplink reachability assessment for massive low-rate IoT terminals.
Vehicular NTN
Space-ground link stability and blind-spot assessment in high-speed mobility scenarios.
Maritime/Aviation
Reachability assessment and backup link design for deep-sea and low-altitude routes.
Emergency Communications
Temporary NTN coverage in disaster zones and service planning for urban re-entry.
Constellation Planning
Comparative end-to-end service capability simulation under different constellation configurations.
Turn satellite signals amid urban high-rises from empirical estimation into deterministic engineering.
乾径科技 MetaRadio · Satellite NTN Vertical Solution