NTNLocalization | 衛星経由3GPP Rel-17/18ユーザー端末（UE）高精度位置測位システム

NTNLocalizationは非地上ネットワーク向けの3GPP標準測位を規定し、タイミングアドバンス（TA）、RTT、衛星ビームを活用してGPS非搭載の5G端末を測位します。

NTNLocalization 3GPP Location Management Function (LMF) Pipeline

Cellular positioning over satellite radio access: Multi-RTT and downlink PRS ranging

Central System: Unmodified 5G NR Smartphone - Standard 3GPP Rel-17 baseband modem

Network Nodes

Unmodified 5G NR Smartphone
LEO Spaceborne gNodeB
Location Management Function (LMF)
E911 Emergency Response (PSAP)

Architectural Protocol Layers

Spaceborne PHY/MAC Layer (3GPP Rel-17 TS 38.300): Doppler compensation, HARQ disabling, and timing advance extension.
Orbital Mesh Routing (CCSDS / Delay-Tolerant Networking): Dynamic topology routing over intermittent laser crosslinks.
Regenerative Core Processing (OpenRAN / 3GPP CU-DU Split): Onboard user plane function (UPF) local breakout.

Key Metrics: < 18ms (LEO Orbit-to-Ground Roundtrip) | 100 Gbps (Optical Crosslink Throughput) | ±48 kHz (Doppler Shift Compensation) | 99.999% (Orbital Constellation Availability)

3GPP Rel-17/18衛星端末測位、タイミングアドバンス測距およびNR-NTN

Core Engineering Areas

Extended Timing Advance (TA) Ranging — Overcoming large satellite propagation delays by expanding Timing Advance range to hundreds of milliseconds to calculate exact slant ranges.
Positioning Reference Signals (PRS) over Satellite — Standardized 3GPP downlink reference signals allowing smartphones to calculate hyperbolic time difference fixes across passing satellites.
Satellite E911 Emergency Compliance — Meeting mandatory federal public safety requirements by providing verified caller locations when dialing SOS over direct-to-cell satellites.

Technical Articles

Related Cluster Architecture Specifications

NonTerrestrialNetwork — 3GPP 5G/6G NTN Satellite Architecture, Direct-to-Cell & Non-Terrestrial Infrastructure
NonTerrestrialNetworks — Multi-Orbit Heterogeneous Constellation Interworking (LEO / MEO / GEO / HAPS)
AirspaceSync — Doppler Compensation, Relativistic Timing & Airspace-Space Synchronization
FSOComm — Free Space Optics, High-Bandwidth Space Laser Communications & Atmospheric Mitigation