---
id: pyrtcm
version: "1.2.0"
license: BSD-3-Clause
license_treatment: permissive
maintenance: active
---

# pyrtcm — RTCM3 protocol parser

License: permissive · Maintenance: active · Downloads: 124.4K/mo

## What it is and what it does

pyrtcm is a Python 3 parser for the RTCM3 differential GNSS protocol, a proprietary standard published by the Radio Technical Commission for Maritime Services. It reads RTCM3 messages from streams (serial, file, or socket), parses them into immutable RTCMMessage objects with named data fields (DF002, DF003, etc.), and exposes those fields as object attributes. The parser handles multiple signal messages (MSM) with configurable output formats (RINEX codes or frequency bands) and supports validation, error handling modes, and extensibility for additional message types.

Typical usage involves creating an RTCMReader with a data stream and iterating through messages, or parsing individual binary RTCM3 frames directly. The library depends only on pynmeagps and installs as a pure Python wheel, making it portable across Windows, macOS, and Linux. It is actively maintained, supports Python 3.10 through 3.14, and carries no known security vulnerabilities.

Use it for:

- Integrate RTCM3 correction data from a base station into a real-time kinematic GNSS application.
- Log and analyze RTCM3 messages from a stream for debugging or auditing differential GPS streams.
- Parse archived RTCM3 binary files to extract and validate satellite correction fields for post-processing.
- Build a GNSS receiver application that consumes RTCM3 messages and applies differential corrections.
- Extend the parser with custom message types for proprietary or vendor-specific RTCM3 variants.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

Parses RTCM3 differential GNSS protocol messages into structured data fields, enabling reading and serialization of GPS/GNSS correction data from streams, files, or sockets.

Yes. pyrtcm is production-stable, actively maintained, has low install friction, carries no known vulnerabilities, and is the only general-purpose RTCM3 parser in the Python ecosystem. Install it if you work with differential GNSS systems, RTK applications, or need to parse RTCM3 correction streams. The BSD-3-Clause license imposes no restrictions on use or redistribution.

## Install

pip install pyrtcm
uv add pyrtcm
poetry add pyrtcm

## Installing pyrtcm

Before you install: Low friction: pure Python wheel with a single runtime dependency. Active maintenance with a release 31 days old and recent commits. Supports Python 3.10 through 3.14.

License in practice: BSD-3-Clause (permissive): you can use, modify, and distribute this package freely in commercial or private projects, provided you include the license notice and disclaimer.

Quickstart:

from pyrtcm import RTCMReader, ERR_LOG

rtr = RTCMReader(stream, quitonerror=ERR_LOG, labelmsm=1)
raw_data, parsed_data = rtr.read()
if parsed_data is not None:
    print(parsed_data)

Requires Python >=3.10; requires an active stream object (file, serial, or socket) that supports read(n) -> bytes method.

Verify before relying:

- Which RTCM3 message types are currently implemented beyond the reference to RTCM_MSGIDS in rtcmtypes_core.py.
- Performance characteristics when parsing high-frequency RTCM streams or large batch files.
- Thread-safety guarantees beyond the statement that RTCMReader.read() is thread-safe if the stream is thread-safe.

## Package facts

- License: BSD-3-Clause (permissive)
- Python support: supports_current
- Install friction: low
- Maintenance: active
- Downloads: 124.4K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

RTCM3 parser, GNSS differential correction, GPS protocol parsing, DGPS message decoder, RTCM message reader, satellite correction data, GNSS protocol library, gnss-gps, protocol-parser, differential-correction

[View on SkillFed](https://skillfed.io/packages/pyrtcm) · [View on PyPI](https://pypi.org/project/pyrtcm/)