Description
The Indian Regional Navigation Satellite System (IRNSS), operational under the name NavIC (Navigation with Indian Constellation), is a satellite-based radio navigation system developed by the Indian Space Research Organisation (ISRO). It is designed to provide accurate position information service to users in India and the region extending up to 1500 km from its boundary. Within the 3GPP context, IRNSS is integrated as a supported Global Navigation Satellite System (GNSS) for User Equipment (UE)-based and UE-assisted positioning methods, alongside other systems like GPS, GLONASS, Galileo, and BeiDou.
From a 3GPP architecture perspective, support for IRNSS is implemented in the UE's positioning capabilities and the network's assistance data delivery mechanisms. The UE must have a compatible GNSS receiver capable of processing IRNSS signals. The network, typically via the Location Management Function (LMF) in 5G or the Enhanced Serving Mobile Location Centre (E-SMLC) in LTE, can provide assistance data to the UE to improve the time-to-first-fix (TTFF), accuracy, and sensitivity of IRNSS-based positioning. This assistance data, defined in 3GPP specifications, includes IRNSS-specific ephemeris, almanac, timing, and ionospheric correction parameters.
The technical operation involves the UE measuring the time of arrival of signals from multiple IRNSS satellites. Using the known satellite positions (from decoded or assisted navigation data) and the measured signal travel times, the UE calculates its own position through trilateration. The IRNSS constellation consists of satellites in Geostationary Orbit (GEO) and Geosynchronous Orbit (GSO), which provides better visibility and higher elevation angles over the Indian region compared to medium Earth orbit (MEO) constellations like GPS, potentially offering improved accuracy in urban canyons. 3GPP specifications define the signal characteristics (e.g., L5 and S bands) and message formats that the UE must handle.
IRNSS integration into 3GPP standards enables mobile network operators in India and surrounding regions to leverage a sovereign, reliable positioning source. This is particularly important for emergency services (like E911/E112), location-based services, network optimization, and various IoT applications. By supporting multiple GNSS constellations, the UE can achieve higher positioning accuracy and robustness through hybrid fixes, especially in challenging environments where signals from one constellation may be blocked.
Purpose & Motivation
The primary purpose of IRNSS/NavIC is to provide India with an independent, regional navigation satellite system, reducing reliance on foreign systems like GPS which are controlled by other governments. This independence is crucial for strategic, security, and sovereignty reasons, ensuring access to precise positioning and timing services during all circumstances, including conflicts or periods of geopolitical tension where access to other GNSS might be degraded or denied.
From a 3GPP standardization perspective, the motivation to integrate IRNSS was driven by market demand and regulatory requirements in India. As smartphone penetration grew, there was a need for devices to support the local navigation system to enable accurate location services for Indian users. Standardization ensures interoperability, allowing any compliant UE to use IRNSS signals if equipped with the appropriate hardware. It also allows network operators to provide IRNSS-specific assistance data efficiently.
Before its inclusion in 3GPP specs, IRNSS-capable devices relied on proprietary implementations, leading to fragmentation and increased cost. Standardization addresses this by creating a unified technical framework for chipset manufacturers and device makers. It solves the problem of seamless integration of a regional GNSS into the global mobile ecosystem, allowing Indian users to benefit from improved location accuracy and service availability while allowing device vendors to have a single, global design that supports all major GNSS constellations through a common 3GPP-defined interface.
Classification
Detected Changes Across Releases
from 3GPP Change RequestsSpecific changes extracted from the „Change history“ tables of 3GPP specifications (32 CRs across 5 releases). Complements the general historical overview above with the evidence-based evolution of this function.
In Release 15, the 3GPP standards introduced formal support for the Indian Regional Navigation Satellite System (IRNSS), also known as NavIC, within the A-GNSS framework. This included defining the "NavIC L1" and "NavIC L5" navigation signals as identifiable GNSS types within the specification's performance requirements. Furthermore, the release included updates to the test requirements for sensitivity with coarse time assistance, specifically updating the explanatory note in the associated power level and satellite allocation table.
- 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 for IRNSS (NavIC) was the formal introduction of its L5 signal, with a carrier frequency of 1176.450 MHz, as a supported navigation signal within the A-GNSS specifications. This addition, alongside updates to other constellations like BeiDou, expanded the range of signals UEs could utilize for assisted positioning. The release also included general enhancements to testing procedures and sensitivity requirements for A-GNSS across the newly supported frequency bands.
- 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 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
- Frequency bands for testing of A-GNSS sensitivity requirements TS 36.171CR0025
- Update B1I signal ICD file to v3.0 in BDS system in A-GNSS TS 37.355CR0259
+ 1 more changes
In Release 17, specific support for the Indian Regional Navigation Satellite System (NavIC) was introduced, including new requirements for A-GNSS support of the NavIC L5 signal. This addition formally integrated NavIC into the 3GPP standards framework alongside other global and regional systems, requiring user equipment to meet defined performance standards when using this signal for assisted positioning.
- 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
- CR on TS 36.171 requirements for support of A-GNSS TS 36.171CR0027
+ 4 more changes
In Release 18, the IRNSS (NavIC) function was enhanced with corrections to its almanac support and system time model support within A-GNSS positioning. Specifically, this included a correction on the NavIC almanac set Information Element (IE) and field descriptions under the KlobucharModelParameter and GNSS-SystemTime. These updates refined the data structures and parameters used for delivering navigation assistance data to the UE.
- GNSS LOS/NLOS assistance information [GNSS LOS/NLOS] TS 37.355CR0446
- SSR Satellite PCV Residuals [Rel18PCV] TS 37.355CR0465
- 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
- Correction on NavIC almanac set IE, and field descriptions under KlobucharModelParamater and GNSS-SystemTime. TS 37.355CR0534
In Release 19, the key new feature for IRNSS (NavIC) was the introduction of NavIC L1 SPS A-GNSS in the LPP protocol. This addition specifically enables Assisted-GNSS positioning support for the NavIC L1 navigation signal, which operates at a carrier frequency of 1575.420 MHz. The update integrates this capability into the existing framework for UE-based and UE-assisted positioning measurements.
- CR for TS 36.171 to introduce BDS B2b signal in A-GNSS TS 36.171CR0032
- 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
- CR for TS 38.171 to introduce BDS B2b signal in A-GNSS TS 38.171CR0031
- Miscellaneous LPP Corrections [GNSS LOS/NLOS] TS 37.355CR0567
Explore further
Broader topics and technologies where IRNSS plays a role.
Defining Specifications
3GPP specifications that define or reference IRNSS, with the latest known release. Sourced from the 3GPP document catalog — see methodology.
| Specification | Title | Release |
|---|---|---|
| TS 36.171 vj10 | A-GNSS Minimum Performance Requirements for UE | Rel-19 |
| TS 37.355 vj20 | LTE Positioning Protocol (LPP) | Rel-19 |
| TS 38.171 vj10 | 5G A-GNSS UE Positioning Requirements | Rel-19 |