Description
GLONASS is a space-based satellite navigation system that constitutes one of the major Global Navigation Satellite Systems (GNSS) alongside the US GPS, European Galileo, and Chinese BeiDou. Within the 3GPP ecosystem, specifications define how User Equipment (UE) can utilize signals from GLONASS satellites (as well as other GNSS constellations) to compute their own position. This capability is a key enabler for 3GPP Location Services (LCS). The system operates by transmitting precise timing signals from a constellation of satellites in Medium Earth Orbit. A GNSS receiver in the UE measures the time delay of signals received from multiple visible satellites; with knowledge of the satellites' orbits (ephemeris data) and the signal transmission time, the receiver can calculate its distance to each satellite and trilaterate its own position.
The integration of GLONASS into 3GPP standards involves specifications across multiple layers. Radio access network specs (e.g., 25.331 for UTRAN, 36.331 for E-UTRAN, 38.331 for NR) define signaling protocols for Assisted GNSS (A-GNSS), where the network can provide assistance data (like satellite almanac and ephemeris) to the UE to significantly speed up the time-to-first-fix and improve sensitivity. Core network specifications cover the positioning protocols and architecture. Furthermore, performance requirements (e.g., in 25.171, 36.171, 38.171) define minimum performance levels for UE receivers supporting GLONASS, including sensitivity, accuracy, and time-to-first-fix metrics under various conditions.
From a network architecture perspective, the UE's GNSS capability, including GLONASS support, is reported to the network. The Location Management Function (LMF) in 5GC or the Enhanced Serving Mobile Location Centre (E-SMLC) in EPS can then use this capability when deciding on a positioning method for a location request. Using multiple GNSS constellations, a technique known as multi-GNSS, improves performance significantly. It increases the number of visible satellites, which is crucial in urban canyons or other challenging environments, leading to better accuracy, availability, and integrity of the position fix. 3GPP's support for GLONASS ensures that UEs can leverage this additional constellation for robust positioning services globally.
Purpose & Motivation
3GPP's incorporation of GLONASS support was driven by the growing demand for accurate and reliable location-based services and regulatory requirements like Enhanced 911 (E911). Relying solely on the US GPS system presented limitations, including potential single points of failure, regional signal vulnerabilities, and sometimes insufficient satellite visibility for a fast, accurate fix. The inclusion of GLONASS as an alternative and complementary GNSS constellation directly addresses these limitations by increasing the number of available navigation satellites.
The primary motivation was to enhance the performance of mobile positioning. By supporting multiple constellations, User Equipment can achieve a position fix more quickly (reduced Time To First Fix - TTFF), with higher accuracy, and with greater reliability, especially in dense urban areas where buildings can block signals from some satellites. This multi-GNSS approach future-proofed 3GPP standards, allowing for the integration of other systems like Galileo and BeiDou as they became operational. It also catered to global market needs, ensuring that mobile devices could provide effective location services worldwide, regardless of regional preferences or the operational status of any single satellite system.
Classification
Detected Changes Across Releases
from 3GPP Change RequestsSpecific changes extracted from the „Change history“ tables of 3GPP specifications (46 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, the updates for the GLONASS function primarily focused on refining the Assisted GNSS (A-GNSS) performance requirements for New Radio (NR). The changes included specific corrections to sensitivity and coarse time assistance requirements, particularly updating the explanatory notes and power level tables within the relevant technical specifications. These modifications ensured the A-GNSS requirements were properly aligned and defined for operation with the 5G NR system.
- Update of the Note 1 in the Power level and satellite allocation table for the Sensitivity Coarse time assistance requirements TS 36.171CR0018
- CR on A-GNSS in 38.171 TS 38.171CR0001
- CR to TS 38.171: Corrections to A-GNSS requirements with NR TS 38.171CR0008
- Update of the Note 1 in the Power level and satellite allocation table for the Sensitivity Coarse time assistance requirements TS 38.171CR0009
In Release 16, the primary update related to GLONASS within the A-GNSS framework was the introduction of support for GNSS Integer Ambiguity Level Indications, enhancing positioning accuracy. The release also included updates to frequency bands for testing A-GNSS sensitivity requirements. Furthermore, clarifications were made to the generic meaning of the term "GNSS" in the positioning protocol specifications TS 36.305 and TS 38.305.
- 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
+ 7 more changes
In Release 17, specific enhancements for GLONASS were not explicitly highlighted in the provided materials. The listed Change Requests primarily focus on introducing and clarifying support for other global navigation satellite systems like BDS and NavIC, along with corrections and clarifications for high-accuracy GNSS metrics, field descriptions, and integrity bounds. The updates aimed at improving overall GNSS service capabilities for the user, as defined by the system's provision of functions, but did not detail new GLONASS-specific signals or procedures.
- 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
- 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
- Requirements for NavIC L5 A-GNSS support TS 38.171CR0025
+ 5 more changes
In Release 18, specific enhancements for GLONASS were introduced, including the provision of Satellite Phase Center Variation (PCV) Residuals via State Space Representation (SSR) data. Furthermore, corrections and clarifications were made to the support for GNSS almanac and UTC model parameters within A-GNSS positioning procedures. These updates aimed to improve the accuracy and reliability of GLONASS positioning assistance provided to the UE.
- 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, there were no specific new features introduced for the GLONASS function. The enhancements for Assisted-GNSS (A-GNSS) in this release focused exclusively on adding support for signals from other global navigation satellite systems, namely the BDS B2b signal and the NavIC L1 SPS signal, across various technical specifications including LPP, LTE, and NR. Therefore, the capabilities for GLONASS assistance remained unchanged from the previous release.
- 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 GLONASS plays a role.
Defining Specifications
3GPP specifications that define or reference GLONASS, with the latest known release. Sourced from the 3GPP document catalog — see methodology.
| Specification | Title | Release |
|---|---|---|
| TR 21.905 vj00 | 3GPP Technical Terms and Definitions | Rel-19 |
| 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 25.331 vj00 | UTRAN RRC Protocol Specification | 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 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 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 44.031 vj00 | Radio Resource LCS Protocol (RRLP) | Rel-19 |