ESP32 RTKPubcaster

ESP32 firmware for streaming RTCM3 corrections from a UM980 GPS receiver to mobile clients via Ably MQTT.

Forked from esp32-ntrip-DUO, redesigned for RTK base station operation with real-time correction streaming.

Hardware

• ESP32-C6 (primary target)
• UM980 GPS receiver (dual-mode RTK capable, 50Hz update rate)
• UART communication (default: TX gpio1, RX gpio3)

Features

• RTCM3 message batching and streaming
• Ably MQTT integration with real-time occupancy tracking
• Conditional publishing (only when subscribers present)
• Web-based configuration interface
• OTA firmware updates with signature verification and rollback
• Configurable RTCM message rates (0.02s to 60s)
• GPS status monitoring and NMEA parsing

Build

Requires ESP-IDF 5.5+:

idf.py build
idf.py -p /dev/ttyUSB0 flash monitor

Configuration

1. Copy main/ably_credentials.h.example to main/ably_credentials.h
2. Add your Ably API keys and channel name
3. Configure via web interface at http://192.168.4.1 (AP mode) or device IP

Architecture

UM980 GPS → UART → ESP32 → Ably MQTT → Mobile Clients
  (RTCM3)           (Batch)   (TLS)     (Subscribe)

See ABLY_SETUP.md for Ably channel configuration details.

License

GPLv3 - See LICENSE file.

Originally derived from esp32-xbee by Nebojsa Cvetkovic, forked as esp32-ntrip-DUO, and redesigned as RTKPubcaster for Ably-based RTK correction streaming.