SparkFun Locates Your Raspberry Pi to Centimeter Precision with Its GPS-RTK Dead Reckoning pHAT

SparkFun has announced a new Raspberry Pi-compatible Hardware Attached on Top (HAT) for anyone needing high-accuracy positioning data via Global Navigation Satellite System (GNSS) reception: The SparkFun GPS-RTK Dead Reckoning pHAT.

"The SparkFun ZED-F9R GPS pHAT is a high precision, sensor fusion GPS board with equally impressive configuration options and takes advantage of u-blox's Automotive Dead Reckoning (ADR) technology," the company explains of its latest launch. "The ZED-F9R module provides a highly accurate and continuous position by fusing a 3D IMU sensor, wheel ticks, a vehicle dynamics model, correction data, and GNSS measurements."

Real-Time Kinematic (RTK) positioning takes location-tracking to a new level, using standard GNSS signals — including from the Global Positioning System (GPS) constellation — plus a stream of correction data to deliver centimeter-level positioning. "RTK-capable GPS receivers used to be thousands of dollars and were limited to professional surveyors and government groups," SparkFun claims. "Thanks to science, math, and economics, RTK receivers are now less than $300."

The SparkFun GPS-RTK Dead Reckoning pHAT is, as the company says, built around the u-blox ZED-F9R, giving it 184 GNSS reception channels and support for GPS, GLONASS, Galileo, and BeiDou constellations. The module is mounted on a HAT-format board with Qwiic connector and USB Type-C, along with a 40-pin general-purpose input/output (GPIO) header designed for connection to a Raspberry Pi — but also compatible, the company says, with the NVIDIA Jetson Nano, Google Coral Development Board, and "any single computer with the 2×20 [GPIO] form factor."

The HAT is only SparkFun's latest in a string of extreme-precision location-sensing devices. Back in June the company unveiled the RTK Reference Station, described as its "most capable" GNSS receiver and logger yet; back in 2021 the company showed off the RTK Express, which upgraded the still-earlier RTK Surveyor.

For those eager to take advantage of the HAT's centimeter-level precision, though, there's a catch: "The ZED-F9R can only operate as a rover," SparkFun says of the module's capabilities, "so you will need to connect to a base station" in order to receive the correction data which provides the top level of positioning accuracy.

The SparkFun GPS-RTK Dead Reckoning pHAT is now available on the SparkFun store for $289.95 before volume discounts.