●Description

The RTK Express Plus 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 Plus 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 Plus is a Bluetooth(R) enabled multi-band GNSS receiver with built-in IMU based on the ESP32 from Espressif and the ZED-F9R 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.

The RTK Express Plus adds an internal IMU (ZED-F9R) to combine real-time GNSS tracking with advanced sensor fusion. The result is accurate automotive positioning even when GNSS is lost in tunnels, parking garages, etc. The downside is the ZED-F9R does not support a base station or generating RTCM corrections. If you are implementing your own RTK base station, consider using products based on the ZED-F9P. The IMU algorithms only apply to automotive applications and will not increase or decrease regular 'clear view of the sky' positioning performance.

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(R). 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 Plus 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.

Get Started With the SparkFun RTK Express Guide

●Features

GNSS Receiver: ZED-F9R

• Concurrent reception of GPS, GLONASS, Galileo and BeiDou
• Receives both L1C/A and L2C bands
• Built-in IMU (triple axis accel, triple axis gyro)
• 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(R) Transceiver: ESP32 WROOM

• Xtensa(R) 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(R) (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
• 1x microSD Socket for optional logging

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