Overview
ISO 24245:2023 - Space systems - Global navigation satellite system (GNSS) receiver class codes - defines a standardized set of class codes that describe how GNSS receivers process signals from radionavigation satellites. The standard applies to all types of GNSS receiver devices and codifies receiver capabilities for positioning, timing, and messaging functions. It is intended to make product selection, procurement, development and policy decisions more transparent by harmonizing how receiver signal-processing features are reported.
Key topics and technical requirements
- Scope and exclusions
- Applies to all GNSS receiver devices.
- Not applicable to satellite condition, radio propagation environment (multipath, masking), additional external antennas, or extra application software in the receiver.
- Code system
- Positioning codes (examples): C10 (no augmentation), C11 (DGNSS / OSR correction), C16 (SSR correction), C20/C25/C26 (single/dual/multi-frequency or DFMC and SBAS-related classes).
- Timing and messaging sections are defined separately (e.g., T1/T2 for timing, M1/M2 for messaging - see standard).
- P‑series codes express input/output correction handling (e.g., P06, P11, P16, P21, P26).
- An “a” suffix (for example, C10a, P11a) denotes receiver capability with GNSS signal authentication.
- Key concepts defined
- Code-based positioning (code-phase measurement without integer ambiguity resolution).
- Phase-range (carrier-phase ranging with integer ambiguity resolution).
- Distinction between OSR (observation-space representation) and SSR (state-space representation) corrections and their geographic/functional scope.
- The standard includes terms, abbreviations and classification rules to determine how to label a receiver.
Practical applications
- Manufacturers use the codes to describe product capabilities consistently in datasheets and marketing.
- Procurement teams and system integrators compare receivers by standardized class codes rather than proprietary feature lists.
- Regulators, government agencies and policy makers incorporate classification into procurement or certification frameworks.
- Developers and service providers (e.g., telecom, surveying, UAS, timing infrastructure) use codes to match receiver capabilities to application requirements (single vs. dual-frequency, SSR support, authentication).
Related standards and bodies
- ISO/TC 20 (Aircraft and space vehicles) prepared the document.
- Related GNSS and correction standards/bodies referenced or relevant in practice: RTCM, SBAS, ICG and GNSS constellation technical specifications. (Consult ISO 24245:2023 for bibliographic details.)
Keywords: ISO 24245:2023, GNSS receiver class codes, GNSS receiver classification, SSR, OSR, DFMC, SBAS, code-based positioning, phase-range, GNSS authentication.
