RTKino is an open-source firmware that turns an ESP32-S3 and a u-blox ZED-F9P into a full-featured RTK GNSS rover and base station, with a modern web interface and standalone OLED operation. Designed and tested — sometimes with pain and frustration — in real-world conditions, not in the lab.

Important: Please read the Disclaimer and Ethical Use Notice before using this software.

RTKino was built from real-world surveying needs, not from a software-first approach.

It has been shaped through practical use in the field, with AI-assisted tools used to support development and speed up implementation.

The focus of this project is function, reliability, and real usability.

• NTRIP Client with automatic GGA forwarding (5-second interval) for VRS services
• TCP Input for local LAN base stations or LoRa radio links
• Multi-profile management with quick switching between correction sources
• Real-time RTK status with audible buzzer alerts on fix state changes
• RTCM statistics showing message types, counts, CRC errors, and data freshness
• Tested with professional NTRIP services: HxGN SmartNet, TPOS, SPIN-GNSS, Pegaso VRS

• Fixed position mode with manual LLH coordinate entry
• Survey mode with configurable averaging (30–300 seconds)
• Saved base stations with names, coordinates, and antenna parameters
• Professional antenna height correction: ground point → ARP → phase center (see Antenna Survey)
• NTRIP Server (pusher) to external casters
• TCP Server on configurable local port
• TCP Client to external TCP endpoints
• MSM7 (4 constellations) or MSM4 (3 constellations) RTCM output
• One-click switch between Base and Rover modes

RTKino includes a complete point survey system.

• Timed measurements with configurable duration and sampling interval
• Quality gate with thresholds for horizontal accuracy, PDOP, and satellite count
• Full GNSS snapshot per point:
  • NAV-HPPOSLLH (high-precision geodetic coordinates)
  • NAV-HPPOSECEF (high-precision cartesian coordinates)
  • NAV-DOP (all 7 DOP values: GDOP, PDOP, HDOP, VDOP, NDOP, EDOP, TDOP)
  • NAV-COV (position covariance matrix: NN, EE, DD, NE, ND, ED)
  • NAV-RELPOSNED (baseline components and standard deviations)
• Point codes with customizable categories (editable via web UI)
• Survey management with create, list, activate, export, and delete operations
• GeoJSON and CSV export of survey data

RTKino ships with a default set of Italian point codes designed for compatibility with widely used Italian surveying software.
These codes should enable seamless CAD export with automatic blocks and symbology.

The point code list is fully editable from the WebUI: go to Settings → Point Codes, modify the JSON as needed, and hit Save. Use Reset to restore the Italian defaults at any time.

Generic English codes available: if you prefer an English code set, copy the contents of docs/point_codes_EN.json and paste them into the Point Codes editor.

Navigate to design points with real-time guidance on the OLED display or web interface.

• Import target points from CSV, GeoJSON, or directly from RTKino surveys
• Live navigation showing 2D distance, height difference, and azimuth
• Point list management with file-based organization

Log raw GNSS observations for post-processing kinematic (PPK) workflows.

• Raw UBX logging to SD card at configurable rates (1–15 Hz)
• NTP or GNSS-synced timestamps for automatic file naming
• Hardware switch (GPIO) for hands-free logging control
• Periodic flush to prevent data loss on power failure

• Multi-WiFi with priority-based network selection
• Access Point mode for offline configuration (192.168.4.1)
• BLE (Bluetooth Low Energy) via Nordic UART Service — compatible with SW Maps, GNSS Master, and Lefebure NTRIP Client
• BLE pairing with 6-digit PIN and encrypted connection
• mDNS for easy access via http://rtkino.local/
• TCP viewer streaming NMEA/UBX on port 1234
• OTA firmware update via web browser
• Configuration backup/restore as JSON

Web UI — Full-featured responsive dashboard accessible from any browser (smartphone, tablet, laptop). Real-time position display, NTRIP/TCP configuration, base station setup, survey management, stakeout navigation, settings, system logs, and configuration backup/restore.

OLED + Rotary Encoder — For standalone fieldwork without a phone. Navigate menus, select survey codes, take measurements, browse stakeout points, toggle connections, and monitor RTK status — all from a 128×64 pixel display and a single rotary knob.

• Lolin S3 Pro (recommended — integrated SD slot, native I2C connector)
• Any ESP32-S3 board with 16 MB Flash and 8 MB PSRAM

• Ardusimple simpleRTK2Bpro
• SparkFun GPS-RTK-SMA
• Any ZED-F9P breakout with UART2 + I2C access

ESP32-S3 GPIO          ZED-F9P
─────────────          ───────
GPIO 40 (RX)  ◄─────  UART2 TX   (NMEA/UBX/RTCM output)
GPIO 39 (TX)  ─────►  UART2 RX   (RTCM input for rover)
GPIO 42 (RX)  ◄─────  UART1 TX   (RAW data for logging)

GPIO 9  (SDA) ◄────►  I2C SDA    (configuration via VALSET/VALGET)
GPIO 10 (SCL) ◄────►  I2C SCL

GPIO 17       ◄─────  Log Switch  (active LOW, internal pullup)
GPIO 5        ─────►  Buzzer      (PWM output)

Pin assignments are defined in include/config.h and can be adapted to other ESP32-S3 boards by adding a new board definition.

Every tagged release is automatically built by GitHub Actions and published with everything you need to flash — no development tools required.

Option 1 — Web Flasher (zero install)

The easiest method. Works directly from a Chromium-based browser (Chrome, Edge, Brave).

1. Connect the ESP32-S3 via USB
2. Open the RTKino Web Flasher
3. Click "Install RTKino" and select the serial port
4. Done in ~60 seconds

Option 2 — Release ZIP (Windows / macOS / Linux)

1. Download the latest rtkino-vX.X.X-lolin_s3_pro.zip from Releases
2. Extract the folder
3. Connect the ESP32-S3 via USB
4. Run the flash script:
   • Windows: double-click flash.bat
   • macOS / Linux: ./flash.sh

The ZIP includes standalone esptool binaries for all platforms — no Python or PlatformIO needed.

Option 3 — OTA update (RTKino already running)

1. Download only firmware.bin from Releases
2. Open the RTKino web interface → Menu → OTA Update
3. Upload firmware.bin and wait for the automatic reboot

For detailed instructions, troubleshooting, and manual esptool commands, see the full Flashing Guide.

For development or custom builds:

git clone https://github.com/flyingsurveyor/RTKINO.git
cd RTKINO

# Build and upload
pio run -t upload

# Monitor serial output (optional)
pio device monitor -b 115200

Requires PlatformIO CLI or IDE extension and a USB-C data cable.

First of all make sure your Zed-F9P firmware version is 1.51 (latest) or some UbxValset messages may be different from those in RTKino.

RTKino requires specific message and port settings on the ZED-F9P. A ready-to-use configuration file is provided in docs/ZEDCONF_RTKino.txt.

To apply it:

1. Connect the ZED-F9P to your computer via USB
2. Open u-center (v2 or legacy)
3. Go to Tools → Receiver Configuration
4. Select ZEDCONF_RTKino.txt and click Transfer file → GNSS
5. Wait for completion
6. Go to Messages view → UBX-CFG-CFG, select Save current configuration then click to Send the Message
7. The Zed-F9P is now configured for RTKino. You can disconnect it from USB.

This step is only needed once on a new or existing ZED-F9P module. The configuration is stored in the receiver's flash memory and persists across power cycles.

1. Insert a FAT32-formatted SD card
2. Power on — the OLED shows the RTKino splash screen
3. If no WiFi is configured, AP mode starts automatically:
   • SSID: rtkino_AP
   • Password: rtkino_zedf9p
4. Connect to the AP and open http://192.168.4.1
5. Configure WiFi credentials in Settings → WiFi Profiles
6. Reboot to connect to your network
7. Access RTKino at http://rtkino.local/ or its IP address

/gnss/
├── wifi.txt                    # WiFi profiles (priority;ssid;password)
├── ntrip_in_list.txt           # NTRIP rover profiles
├── ntrip_out_list.txt          # NTRIP pusher profiles
├── tcp_in_list.txt             # TCP input profiles
├── tcp_out_client_list.txt     # TCP output client profiles
├── bases.txt                   # Saved base stations
├── antennas.txt                # Antenna models with ARP offsets
├── ntp.txt                     # NTP server hostname
├── ble_name.txt                # BLE device name
├── ble_pin.txt                 # BLE pairing PIN
├── mdns.txt                    # mDNS hostname
├── buzzer_melody.json          # Custom buzzer sounds (optional)
├── system_log_01..03.txt       # Rotating system event logs
└── log_YYYYMMDD_HHMMSS.ubx    # Raw GNSS observation logs

See docs/examples/ for sample configuration files.

pio device monitor -b 115200

Key log messages:

• [NTRIP] Enabled — NTRIP client started
• [RTCM] type=1005 len=XX — Receiving base station position
• [TMODE] Read successful: mode=2 — Base mode active (fixed)
• [FIX] Acquired: Float -> RTK Fixed — RTK fix achieved
• [MEM] Heap: XXXXX free — Memory status

1. Remove the SD card
2. Delete the /gnss/ folder
3. Reinsert the card and reboot
4. Reconfigure via AP mode

RTKino is actively developed and field-tested in real surveying work including topographic mapping, drone ground control, agricultural monitoring, and construction stakeout. And more.

Current version: v1.0.0 (March 2026)

RTKino firmware is considered stable (v1.0), but the hardware is still evolving.

Current setups are intentionally simple and reproducible, often built with:

• breakout boards (ESP32-S3, ZED-F9P)
• jumper wires
• prototyping boards
• custom enclosures

In other words: functional, field-tested, but not yet refined. RTKino prioritizes function over appearance — it is built to work first.

• Dedicated carrier PCB for ESP32-S3 + ZED-F9P
• Integrated power system (18650-based)
• Robust connectors and cleaner wiring
• Optional LTE module integration
• Improved enclosure design (3D printed case)

Hardware designs will be shared once they reach a stable and reproducible state.

Until then, RTKino remains fully usable with simple DIY builds.

Contributions are welcome. Please read CONTRIBUTING.md before submitting.

This project is licensed under the GNU Affero General Public License v3.0 (AGPL-3.0).

You are free to use, modify, and distribute this software. If you modify it, you must release your source code under the same license. Network use counts as distribution.

See LICENSE for the full text.

Please read the Ethical Use Notice.

RTKino is not a commercial product. It is provided as-is, without warranty of any kind. The user is solely responsible for validating all measurements and ensuring fitness for their intended application.

Please read the full Disclaimer.

• Tim Everett / RTKLIBExplorer for keeping RTKLIB alive and evolving
• u-blox for the ZED-F9P and its excellent documentation
• Espressif for the ESP32-S3 platform
• NimBLE-Arduino by h2zero
• SdFat by Bill Greiman
• RTK2Go free NTRIP caster service
• The open-source GNSS community

Made with ❤️ for land surveying

FlyingSurveyor · Italy