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SparkFun RTK Reference Station

Designed and manufactured in Boulder, Colorado, USA, the SparkFun RTK Reference Station is the perfect solution for your high-precision geolocation, surveying, and time reference needs. For basic users, it is incredibly easy to set up a fixed location NTRIP server, enabling RTK for rovers and even as an NTP server for equipment synchronization and an astoundingly accurate time base.

RTK is short for Real Time Kinematics. A satellite positioning receiver capable of RTK takes in the normal signals from the Global Navigation Satellite Systems (GNSS) along with a correction data stream to achieve improved positional accuracy. GNSS includes satellites from GPS (USA), GLONASS (Russia), Beidou (China), Galileo (Europe), plus special additional satellites (e.g., SBAS and QZSS). On their own, these signals will deliver ~30cm positional accuracy. An RTK receiver takes in an additional Real Time Correction Message (RTCM) data stream and then calculates the device's location with 1cm accuracy in real-time. RTK works best when the correction data is generated locally; the 'Rover' receiver accuracy degrades as the distance (baseline) between it and the 'Base' generating the corrections increases. With just a few minutes of setup, the SparkFun Reference Station allows you to generate that correction data locally and share it via Ethernet!

Under the hood, the Reference Station is based on the ESP32-WROOM processor and u-blox ZED-F9P multi-band GNSS module. It runs the same open-source firmware as our other RTK products. The Reference Station has 10/100 Mbps Ethernet connectivity and it can be powered by Power-over-Ethernet (PoE). The microSD card is connected via a 4-bit SDIO interface, providing an order of magnitude improvement in read and write speed. Similarly, the u-blox ZED-F9P GNSS module is connected via a high-speed SPI interface, also providing an order of magnitude improvement in the GNSS data transfer speed. Want to log RAWX and SFRBX from all constellations at 20Hz? With this product, you can! We also included an ATECC608A crypto co-processor if you want to write your own firmware and use the Reference Station for crypto mining/space weather station applications or to secure/authenticate your GNSS data.

Need an affordable Network Time Protocol (NTP) time server for your Ethernet network? We've got you covered. The Reference Station can also act as an NTP server. Having your own NTP server allows the computers on your Ethernet network to achieve much closer clock synchronization. The Reference Station supports DHCP by default, but you can give it a fixed IP address if you want to. DNS, gateway, and subnet mask are all configurable too.

We've designed the Reference Station to be robust and lab friendly. Internally, all of the electronics (except the Qwiic OLED display) are mounted on a single circuit board. ESP32 WiFi / Bluetooth antenna, GNSS antenna, and timing pulse output are all connected via robust SMA connectors. IO connections are made via a robust 3.5mm header with cage screw connections. The timing pulse SMA output is 3.3V by default but can be configured for 5V if needed and is good for 100kHz (but not in NTP mode, that's fixed at 1Hz). The Reset and Mode switches have been positioned carefully; Mode is easily clicked when required, and Reset is flush and requires a more assertive press. (This helps prevent any accidental resets when connecting to the ESP32 USB port.) The edge of the microSD card protrudes slightly when inserted, making it easy to eject and re-insert. Then there is the beautiful custom extruded aluminum case with machined end panels and slotted flanges, making it simple to install the Reference Station in a weatherproof enclosure up on the roof or in your server rack.

The Reference Station has multiple power options. It can be powered by any or all of the ESP32 USB connection; the u-blox ZED-F9P USB connection; a separate USB-C power port on the rear; Power-over-Ethernet (36V to 57V); a 5V pin on the IO screw header. The 5V IO pin can accept a maximum of 5.5V if required. The GNSS SMA antenna connection provides 5V for the included active L1/L2 antenna instead of the usual 3.3V. The Reference Station provides both short-circuit and open-circuit detection and protection for the antenna cable; symbols will flash on the OLED display if a short or open is detected.

This device can be used in multiple modes, including:

  • GNSS Base Station with NTRIP - RTCM corrections are sent to a Caster over Ethernet
  • Network Time Protocol (NTP) Server - providing high-accuracy timing data to other machines via an Ethernet network

Those two modes are the ones most users will want to use, but you never cease to amaze us with the variety of ways you use our products. Should you want to, the Reference Station can also be used as:

  • GNSS Positioning Receiver (~30cm accuracy) - also known as 'Rover'
  • GNSS Positioning with RTK (1.4cm accuracy) - also known as 'Rover with RTK Fix' - using NTRIP RTCM correction data over Ethernet or from your phone via Bluetooth
  • GNSS NMEA/UBX TCP Client - sending NMEA and/or UBX navigation data to a remote server using TCP over Ethernet

Please see the Hookup Guide for more details on which configurations we've tried and tested.

Our kit includes everything you need to get up and running. Please see the 'Includes' tab for more information.

  • Cased Reference Station
  • L1/L2/L5 GNSS Surveying Antenna
  • Reinforced RG58 TNC-SMA Cable (10m)
  • SMA WiFi / Bluetooth Antenna
  • 32GB microSD Card (Class 10)
  • USB-C Power Supply (5V 1A wall charger)
  • USB-C Cable (A to C, 2m)
  • Ethernet Cable (CAT-6, 1m)
  • ESP32-WROOM processor
    • Reverse Polarity (RP) SMA WiFi / BT antenna connection
  • u-blox ZED-F9P multi-band GNSS module
    • Connected via SPI for high-speed data transfer
  • microSD socket
    • Connected via 4-bit SDIO for high speed read and write
  • WIZnet W5500 Ethernet interface
    • 10/100 Mbps with auto-negotiate
  • ATECC608A Crypto Co-processor
    • Future upgrade; not currently supported by the RTK firmware
  • OLED display
  • SMA Time Pulse output
    • 3.3V default
    • Configurable for 5V
    • 100kHz maximum usable output
    • 1Hz output in NTP mode
  • SMA GNSS antenna connection
    • 5V power for an active antenna
    • Short-circuit detection
    • Open-circuit detection
  • Custom extruded aluminum case with machined end panels
    • IP42 ingress protection
    • A weatherproof enclosure is required for outdoor use
  • Matte-effect front and rear stickers
  • Power options:
    • ESP32 USB-C connector
    • u-blox GNSS USB-C connector
    • Rear USB-C power connector
    • Power-over-Ethernet (36V - 57V)
    • 5V I/O screw terminal (5.5V Maximum)

SparkFun RTK Reference Station Product Help and Resources

How to Build a DIY GNSS Reference Station

October 15, 2020

Learn how to affix a GNSS antenna, use PPP to get its ECEF coordinates and then broadcast your own RTCM data over the internet and cellular using NTRIP to increase rover reception to 10km!

Setting up a Rover Base RTK System

October 14, 2020

Getting GNSS RTCM correction data from a base to a rover is easy with a serial telemetry radio! We'll show you how to get your high precision RTK GNSS system setup and running.

How to Upgrade Firmware of a u-blox GNSS Receiver

March 26, 2021

A few steps and you'll upgrade to the latest features on a u-blox GNSS receiver.

SparkFun RTK Reference Station Hookup Guide

May 23, 2023

Setup the RTK Reference Station in minutes and start sending RTCM NTRIP corrections to your favourite caster.

Core Skill: DIY

Whether it's for assembling a kit, hacking an enclosure, or creating your own parts; the DIY skill is all about knowing how to use tools and the techniques associated with them.


Skill Level: Noob - Basic assembly is required. You may need to provide your own basic tools like a screwdriver, hammer or scissors. Power tools or custom parts are not required. Instructions will be included and easy to follow. Sewing may be required, but only with included patterns.
See all skill levels

Core Skill: Programming

If a board needs code or communicates somehow, you're going to need to know how to program or interface with it. The programming skill is all about communication and code.

3 Programming

Skill Level: Competent - The toolchain for programming is a bit more complex and will examples may not be explicitly provided for you. You will be required to have a fundamental knowledge of programming and be required to provide your own code. You may need to modify existing libraries or code to work with your specific hardware. Sensor and hardware interfaces will be SPI or I2C.
See all skill levels

Core Skill: Electrical Prototyping

If it requires power, you need to know how much, what all the pins do, and how to hook it up. You may need to reference datasheets, schematics, and know the ins and outs of electronics.

3 Electrical Prototyping

Skill Level: Competent - You will be required to reference a datasheet or schematic to know how to use a component. Your knowledge of a datasheet will only require basic features like power requirements, pinouts, or communications type. Also, you may need a power supply that?s greater than 12V or more than 1A worth of current.
See all skill levels


Looking for answers to technical questions?

We welcome your comments and suggestions below. However, if you are looking for solutions to technical questions please see our Technical Assistance page.

  • Member #437078 / about 10 months ago / 1

    Can this operate as both an NTP server and an NTRIP Base at the same time? I tend to think not after reading the docs (since they are different modes), but I wanted to ask to confirm.

    • PaulZC / about 10 months ago / 1

      Hi, Sorry, unfortunately not. The NTP and Base modes are very different - internally. Best wishes, Paul

  • Member #1640632 / about a year ago / 1

    I am very excited about this. Can I mount the receiver 60 metres away from the antennae? What is the maximum cable length recommended? What cable/extension would you recommend?

  • Yashu / about a year ago / 1

    Can you advise when the unit that also includes a uBlox NEO-D9S L-Band Rx will be available?

    • It's on the roadmap. Perhaps by the end of 2023 but we don't have a definite date.

Customer Reviews

4 out of 5

Based on 4 ratings:

Currently viewing all customer reviews.

1 of 1 found this helpful:

sweet box

this device has made precision agriculture possible here in hawaii where there is no commercial rtk coverage. it was easy to setup with the supplied documentation, and our nonprofit now broadcasts ntrip corrections over the rtk2go network as the pureknfbase. i probably could have made my own cheaper following the DIY instructions, but i'm glad i got this unit because it's an all in one, well built, simple ui, solid sexy looking device. seems to be reliable a few weeks in with 100% uptime since i first booted it. thanks sparkfun for making this much functionality affordable.

0 of 2 found this helpful:


the device came without firmware.The support was bad.The device is working now. I'm not happy about buying

I like the simplicity of setting it up

After lots of research, watching YouTube videos, and checking out forums, I finally took the plunge and bought this product. It's like a ready-to-go base station setup that makes providing correction data to my rover super easy. Setting up the NTRIP corrections for my Emlid rover was a breeze, and I was up and running in just a few minutes. No complaints at all - it even came with an SD card and a nice long antenna cable. And the best part? It didn't break the bank! I'd totally recommend it to others looking for a simple and affordable solution.

0 of 1 found this helpful:

Good thing... but for researchers, not for professional use

  1. WiFi can be one more channel for Reference station NTRIP Server/Caster... not only Ethernet port.
  2. Settings are returned to default values without any reason...
  3. Power interruption reset all settings... and device go to Rover or Base without any reason
  4. The price is the best thing here...