SparkFun RTK Express Kit

The RTK Express Kit has everything you need to get centimeter level global positioning measurements using GNSS RTK. We've created a handy carrying case to protect the most expensive bits, allowing you to quickly attach the L1/L2 antenna and RTK Express housing to the pole or tripod of your choice. The kit includes all the antenna bits, cables and chargers you need to jump right into the field.

The RTK Express is a Bluetooth enabled multi-band GNSS receiver based on the ESP32 from Espressif and the ZED-F9P from u-blox. Power it up and you'll have 300mm approximate accuracy out of the box and 14mm accuracy with RTCM corrections. This kit provides the L1/L2 antenna, adapters, interface cables, and chargers needed for general GNSS use.

We generally recommend using your cellular phone as the radio backhaul for RTCM but you can also use your own, higher power radios as long as they support 57600bps. We also recommend logging all data to your phone over Bluetooth. This is as simple as checking a box within SW Maps. But if you prefer to do long surveys, or need to deal with RAWX measurements where a phone will not be present, a microSD card should be purchased (any size up to 32GB).

Please keep in mind that you will need to provide your own mono-pod or tripod as well as a cell-phone type holder for securing the RTK Express to your mono-pod or tripod. We've found this style clamp and this style clamp work well. Your mileage may vary.

Note: The L1/L2 antenna has a 5/8" thread which will fit most surveying platforms. The kit includes a 5/8" to 1/4" adapter as well which will fit most camera mono-pods and tripods. You may need additional adapters for your specific equipment.

GNSS Receiver: ZED-F9P

  • Concurrent reception of GPS, GLONASS, Galileo and BeiDou
  • Receives both L1C/A and L2C bands
  • Current: 68mA - 130mA (varies with constellations and tracking state)
  • Time to First Fix: 25s (cold), 2s (hot)
  • Max Navigation Rate:
    • PVT (basic location over UBX binary protocol) - 25Hz
    • RTK - 20Hz
    • Raw - 25Hz
  • Horizontal Position Accuracy:
    • 2.5m without RTK
    • 0.010m with RTK
  • Max Altitude: 50km (31 miles)
  • Max Velocity: 500m/s (1118mph)

Bluetooth® Transceiver: ESP32 WROOM

  • Xtensa® dual-core 32-bit LX6 microprocessor
  • Up to 240MHz clock frequency
  • 16MB of flash storage
  • 520kB internal SRAM
  • Integrated 802.11 BGN WiFi transceiver
  • Integrated dual-mode Bluetooth® (classic and BLE)
  • Hardware accelerated encryption (AES, SHA2, ECC, RSA-4096)
  • 2.5 µA deep sleep current

Overall Device

  • Internal Battery: LiPo 1300mAh with 500mA charging
  • Radio Port: 3.3V TTL Serial (57600bps RTCM TX/RX)
  • Data Port: 3.3V TTL Serial (115200bps NMEA)
  • Embedded OLED Display for available satellites, data logging, and more.
  • Push button controls
  • Weight: 162g (entire device including battery)
  • Dimensions: 132mm x 101mm x 32mm (5.2in x 3.9in x 1.2in)
  • 1x Qwiic Connector

GNSS Multi-Band L1/L2 Surveying Antenna

  • Gain: ≥5dBi
  • LNA Gain: 40dB
  • Reception Frequencies
    • L1: 1555 to 1615MHz
    • L2: 1198 to 1278MHz
  • 50 Ohm Antenna Impedance
  • Overall antenna weight: 335g
  • Bare antenna element weight (including MMCX connector, with RF shield): 160g
  • Dimensions: 148 x 55mm
  • Waterproof IP67
  • Connector: Female TNC

SparkFun RTK Express Kit 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!

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 Express Hookup Guide

June 21, 2021

Learn how to use the enclosed RTK Express product to achieve millimeter level geospatial coordinates.

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.

2 DIY

Skill Level: Rookie - Basic hand tools are required and instructions will allow more freedom. You may need to make your own decisions on design. If sewing is required, it will be free-form.
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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.
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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.

2 Electrical Prototyping

Skill Level: Rookie - You may be required to know a bit more about the component, such as orientation, or how to hook it up, in addition to power requirements. You will need to understand polarized components.
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Comments

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.

  • The text recommends this for a back haul radio: Serial Telemetry Radio Kit - 915MHz, 500mW Retired WRL-17255 Note:Retired Product This product has been retired from our catalog and is no longer for sale. This page is made available for those looking for datasheets and the simply curious.

    • Sorry, that's confusing. We are waiting for the supplier to get us their new version of the 915MHz radio. I've removed the link for now.

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