Description
The BeiDou Navigation Satellite System (BDS) is a satellite-based radio navigation system owned and operated by China. Within the 3GPP framework, BDS is standardized as a Global Navigation Satellite System (GNSS) for user equipment (UE) positioning. The system architecture comprises three segments: the space segment (satellites), the ground control segment (master control stations, upload stations, monitoring stations), and the user segment (receivers in UEs). The space segment includes a constellation of satellites in geostationary Earth orbit (GEO), inclined geosynchronous orbit (IGSO), and medium Earth orbit (MEO), providing global coverage with enhanced regional service over Asia-Pacific.
BDS operates by transmitting precise timing signals and navigation messages from its satellites. A UE with a BDS receiver measures the time of arrival of signals from multiple visible satellites. Using these measurements and the known satellite positions (ephemeris data from navigation messages), the UE calculates its position via trilateration. The system provides multiple service signals across different frequency bands (e.g., B1, B2, B3), offering open (civilian) and authorized (military/secure) services. The signals use Code Division Multiple Access (CDMA) modulation with specific pseudo-random noise (PRN) codes for satellite identification.
In the 3GPP architecture, BDS is integrated through control plane and user plane positioning protocols defined in specifications such as TS 36.355 (LTE Positioning Protocol - LPP) and TS 38.455 (NR Positioning Protocol A - NRPPa). The network can assist the UE by providing assistance data like satellite ephemeris, almanac, and timing information via the LTE Positioning Protocol (LPP) or NRPPa, which reduces Time To First Fix (TTFF) and improves power efficiency. The Location Management Function (LMF) in the 5G core network or the Enhanced Serving Mobile Location Centre (E-SMLC) in LTE manages these positioning sessions, requesting BDS measurements from the UE or gNB/ng-eNB.
BDS's role is critical for fulfilling regulatory requirements (e.g., emergency caller location), enabling location-based services (LBS), and supporting applications like vehicle tracking, IoT asset monitoring, and navigation. Its integration allows hybrid positioning with other GNSS (like GPS, Galileo) and terrestrial methods (OTDOA, E-CID), enhancing accuracy, availability, and reliability. Performance is characterized by parameters such as accuracy (meter-level for open service), integrity, and continuity, specified in test requirements documents like TS 37.571.
Purpose & Motivation
BDS was created to provide China with an independent, global satellite navigation capability, reducing reliance on foreign systems like GPS (USA) and GLONASS (Russia). Its integration into 3GPP standards addresses the need for diversified and resilient Positioning, Navigation, and Timing (PNT) sources in mobile networks. Prior to its inclusion, cellular positioning primarily depended on GPS, which posed risks related to availability, sovereignty, and service continuity in certain regions or during conflicts.
The motivation for standardizing BDS in 3GPP, starting from Release 8, was to enable worldwide interoperability and support for Chinese satellite signals in commercial mobile devices. This allows network operators and device manufacturers to leverage BDS for improved positioning performance, especially in the Asia-Pacific region where its signals are stronger due to regional satellite augmentation. It solves problems of single-point failure in PNT services and enhances location accuracy in urban canyons or challenging environments through multi-constellation GNSS receivers.
Historically, early cellular positioning methods like Cell-ID offered low accuracy, while later techniques like Assisted-GPS (A-GPS) improved precision but were tied to specific GNSS constellations. BDS integration, alongside other GNSS, provides a more robust and accurate solution, supporting emerging demands from autonomous vehicles, drone navigation, and precise timing for network synchronization. It also fulfills Chinese regulatory mandates for emergency services and national security, ensuring domestic control over critical infrastructure.
Classification
Detected Changes Across Releases
from 3GPP Change RequestsSpecific changes extracted from the „Change history“ tables of 3GPP specifications (61 CRs across 5 releases). Complements the general historical overview above with the evidence-based evolution of this function.
Studied in Rel-8, normative work from Rel-15.
In Release 15, support for the BeiDou Navigation Satellite System (BDS) was formally introduced under the broader framework of A-GNSS (Assisted Global Navigation Satellite System). This extended the existing assisted positioning capabilities, which previously included systems like GPS and Galileo, to now incorporate the Chinese BeiDou constellation. The update standardized BDS support within the OTDOA (Observed Time Difference of Arrival) assistance data procedures for NR (New Radio).
- Introduction of IMU support for OTDOA TS 36.355CR0204
- Update of the Note 1 in the Power level and satellite allocation table for the Sensitivity Coarse time assistance requirements TS 36.171CR0018
- OTDOA Assistance Data Request for NR TS 36.355CR0222
- Addition of TDD UL/DL configuration to OTDOA assistance data TS 36.355CR0213
- SFN offset for OTDOA TS 36.355CR0229
- CR on A-GNSS in 38.171 TS 38.171CR0001
+ 3 more changes
In Release 16, the key new feature for the BeiDou Navigation Satellite System (BDS) was the introduction of support for the modernized B1C signal within the Assisted-GNSS (A-GNSS) framework across both LTE (TS 36.171) and NR (TS 38.171) specifications. This update also included necessary corrections and updates to associated data, such as updating the B1I signal Interface Control Document (ICD) file to version 3.0 and correcting the B2I clock model. Furthermore, the release enhanced positioning capabilities by introducing support for GNSS Integer Ambiguity Level Indications and clarifying terminology related to GNSS across various technical specifications.
- CR for TS36.171, Introduction of BDS B1C in A-GNSS TS 36.171CR0020
- Introduction of B1C signal in BDS system in A-GNSS TS 36.305CR0083
- Introduction of B1C signal in BDS system in A-GNSS TS 37.355CR0248
- Introducing support for GNSS Integer Ambiguity Level Indications TS 37.355CR0252
- CR for TS38.171, Introduction of BDS B1C in A-GNSS TS 38.171CR0011
- Introduction of B1C signal in BDS system in A-GNSS TS 38.305CR0013
+ 14 more changes
In Release 17, the key new developments for the BeiDou Navigation Satellite System (BDS) function included the formal introduction of support for the B2a and B3I signals within the 3GPP specifications. This release also brought clarifications and corrections for the transmission of State Space Representation (SSR) assistance data based on the BDS B1C signal and for BDS orbit ephemeris references to align with the RTCM standard. Furthermore, it introduced requirements for the relative signal power levels of BDS for both LTE (TS 36.171) and NR (TS 38.171) user equipment.
- Introduction of B2a and B3I signal in BDS system and GNSS Positioning Integrity TS 36.305CR0107
- NMEA GGA sentence info in high accuracy GNSS location estimates [HA-GNSS-NMEA] TS 37.355CR0349
- CR on TS 36.171 requirements for relative signal power levels of BDS TS 36.171CR0030
- Correction on the GNSS Orbit and Clock Integrity Bounds in TS 37.355 TS 37.355CR0377
- GNSS SSR BDS orbit emphemeris reference clarification to align with RTCM TS 37.355CR0461
- Field description correction for HA-GNSS metrics TS 37.355CR0474
+ 8 more changes
In Release 18, the BeiDou Navigation Satellite System (BDS) enhancements included the introduction of new assistance information for identifying Line-of-Sight (LOS) and Non-Line-of-Sight (NLOS) GNSS signal conditions and the provision of State Space Representation (SSR) Satellite Phase Center Variation (PCV) Residuals data. These additions, along with miscellaneous corrections for RIL and A-GNSS positioning support elements, were aimed at improving positioning accuracy for services like navigation and route guidance.
- GNSS LOS/NLOS assistance information [GNSS LOS/NLOS] TS 37.355CR0446
- SSR Satellite PCV Residuals [Rel18PCV] TS 36.305CR0118
- SSR Satellite PCV Residuals [Rel18PCV] TS 37.355CR0465
- SSR Satellite PCV Residuals [Rel18PCV] TS 38.305CR0140
- Miscellaneous RIL corrections for GNSS LOS/NLOS [GNSS LOS/NLOS] TS 37.355CR0495
- Correction on GNSS-AlmanacSupport and GNSS-UTC-ModelSupport in A-GNSS positioning TS 37.355CR0518
+ 2 more changes
In Release 19, the key new development for the BeiDou Navigation Satellite System (BDS) function was the formal introduction of the **BDS B2b signal** for Assisted-GNSS (A-GNSS) positioning. This enhancement was specified across multiple technical standards, including those for LTE (TS 36.171), NR (TS 38.171), and the LTE Positioning Protocol (TS 38.305), to integrate this specific signal into the network-assisted positioning framework. The update expanded the range of supported satellite signals for improved positioning accuracy in services like navigation and route guidance.
- CR for TS 36.171 to introduce BDS B2b signal in A-GNSS TS 36.171CR0032
- Introduction of NavIC L1 SPS A-GNSS in LTE Stage 2 specification TS 36.305CR0120
- Introduction of BDS B2b in A-GNSS TS 36.305CR0121
- Introduction of NavIC L1 SPS A-GNSS in LPP TS 37.355CR0532
- Introduction of B2b signal in BDS system in A-GNSS TS 37.355CR0545
- UE request for equalIntegerAmbiguityLevel assistance data [GNSS-EqualIntegerAmbiguity] TS 37.355CR0557
+ 4 more changes
Explore further
Broader topics and technologies where BDS plays a role.
Defining Specifications
3GPP specifications that define or reference BDS, with the latest known release. Sourced from the 3GPP document catalog — see methodology.
| Specification | Title | Release |
|---|---|---|
| TS 22.071 vj00 | 3GPP TS 22.071: Location Services (LCS) Stage 1 | Rel-19 |
| TS 25.172 vj00 | A-GANSS UE Minimum Performance Requirements (FDD) | Rel-19 |
| TS 25.173 vj00 | A-GANSS Performance Requirements (TDD) | Rel-19 |
| TS 25.305 vj00 | UTRAN UE Positioning Stage 2 | Rel-19 |
| TS 25.306 vj00 | UE Radio Access Capabilities Specification | Rel-19 |
| TS 25.331 vj00 | UTRAN RRC Protocol Specification | Rel-19 |
| TS 25.413 vj00 | Radio Access Network Application Part (RANAP) | Rel-19 |
| TS 25.423 vj00 | UTRAN RNSAP Specification | Rel-19 |
| TS 25.433 vj00 | Node B Application Part (NBAP) Protocol | Rel-19 |
| TS 25.453 vj00 | PCAP Protocol Specification | Rel-19 |
| TS 32.808 v1800 | Common User Profile Storage Framework | Rel-8 |
| TS 36.171 vj10 | A-GNSS Minimum Performance Requirements for UE | Rel-19 |
| TS 36.305 vj00 | UE Positioning in E-UTRAN Stage 2 | Rel-19 |
| TS 36.355 vj00 | LTE Positioning Protocol (LPP) | Rel-19 |
| TS 37.355 vj20 | LTE Positioning Protocol (LPP) | Rel-19 |
| TS 37.571 vj00 | UE Conformance for Positioning | Rel-19 |
| TS 38.171 vj10 | 5G A-GNSS UE Positioning Requirements | Rel-19 |
| TS 38.305 vj00 | NG-RAN UE Positioning Stage 2 | Rel-19 |
| TS 38.455 vj10 | NR Positioning Protocol A (NRPPa) | Rel-19 |
| TS 43.059 vj00 | GERAN LCS Stage 2 Specification | Rel-19 |
| TS 44.031 vj00 | Radio Resource LCS Protocol (RRLP) | Rel-19 |
| TS 45.005 vj00 | GSM RF Requirements for MS and BSS | Rel-19 |
| TS 51.010 vj00 | SIM Application Toolkit Conformance Testing | Rel-19 |