With the flick of a switch, two RTK Surveyors can be used to create an RTK system capable of 14mm horizontal positional accuracy. The built-in Bluetooth® connection via an ESP32 WROOM enables the user to use the RTK Surveyor with their choice of GIS application on a phone or tablet. The built in battery allows field use for up to four hours and is compatible with common USB battery banks.

This device can be used in four modes:

• GNSS Positioning (~30cm accuracy)
• GNSS Positioning with RTK (1.4cm accuracy)
• GNSS Base Station
• GNSS Base Station NTRIP Server

In Position mode the device receives L1/L2 signals from a user-provided antenna and the high-grade GNSS receiver provides lat/long and altitude with accuracies around 300mm.

In Positioning with RTK mode the device receives L1/L2 signals from the antenna and correction data from a base station. The correction data can be obtained from a cellular link to online correction sources or over a radio link to a 2nd RTK Surveyor setup as a base station.

In Base Station mode the device is mounted to a temporary position (like a tripod) and begins transmitting correction data over a radio or internet connection. A base is often used in conjunction with a second unit set to ‘Positioning with RTK’ to obtain the 14mm relative accuracy.

In Base Station NTRIP Server mode the device is mounted to a semi or permanently fixed position (like a roof) and connects over WiFi to transmit the correction data to a NTRIP caster so that any rover can access the correction data over a cellular or internet connection. This type of base is a very easy way to setup a very precise absolute correction source.

Two cables are provided with the RTK Surveyor allowing a user to plug on our easy to use Serial Telemetry Radios or their own radio link. If a local correction source is within 10km, a user can also use their phone to provide correction data over the Bluetooth® link (no external radio needed!).

Note: The SparkFun RTK Surveyor is just the enclosed device and does NOT include an antenna, serial telemetry radio, or associated mounting pieces. These items will need to be purchased separately from the Hookup Accessories below.

This unit requires an external antenna along with a TNC to SMA cable.

Sparkfun RTK Comparison

RTK Surveyor

A versatile enclosed device that can be used either for centimeter accuracy positioning or as a base station.

RTK Express

We’ve taken everything that is good about the RTK Surveyor and upgraded with a display, a better battery and an accelerometer for digital leveling.

RTK Express Plus

RTK Express Plus adds an internal IMU to combine real-time GNSS tracking with advanced sensor fusion. The result is accurate positioning even when GNSS is lost in tunnels, parking garages, etc.

Features

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 1000mAh with 500mA charging
• Radio Port: 3.3V TTL Serial (57600bps RTCM TX/RX)
• Data Port: 3.3V TTL Serial (115200bps NMEA)
• Weight: 132g (entire device including battery)
• Dimensions: 118mm x 79mm x 30mm (4.7in x 3.1in x 1.2in)
• 1x Qwiic Connector
• 1x microSD Socket for optional logging

Resources