SparkFun GPS-RTK Dead Reckoning pHAT for Raspberry Pi

The SparkFun ZED-F9R GPS pHAT is a sensor fusion GPS board that boasts high precision and impressive configuration options. It utilizes u-blox's Automotive Dead Reckoning (ADR) technology to provide an extremely accurate and continuous position. This is achieved by fusing a 3D IMU sensor, wheel ticks, a vehicle dynamics model, correction data, and GNSS measurements.

The ZED-F9R module is a 184-channel u-blox F9 engine GNSS receiver, capable of receiving signals from the GPS, GLONASS, Galileo, and BeiDou constellations with an astounding accuracy of approximately 0.01 meters. This accuracy is achievable with an RTK navigation solution when used in conjunction with a correction source. Please note that the ZED-F9R can only operate as a rover, necessitating a connection to a base station. The module supports the concurrent reception of four GNSS systems, and the combination of GNSS and integrated 3D sensor measurements on the ZED-F9R allows for accurate, real-time positioning rates of up to 30Hz.

The ZED-F9R is the ultimate solution for autonomous robotic applications that require precise positioning under challenging conditions. This pHAT maximizes position accuracy in dense cities or covered areas. Even under poor signal conditions, it provides continuous positioning in urban environments and remains available during complete signal loss, such as in short tunnels and parking garages.

The SparkFun ZED-F9R GPS pHAT communicates with the module using the Raspberry Pi's serial UART by default and can be easily stacked on a Raspberry Pi, NVIDIA Jetson Nano, Google Coral, or any single-board computer with the 2x20 form factor, thanks to its pre-soldered headers. A Qwiic connector is provided for connecting Qwiic-enabled devices, and a few 2.54mm-spaced pins from the u-blox receiver have been broken out for convenience.

The ZED-F9R is configurable using the popular but dense Windows program u-center. This allows configuration of many different functions, including baud rates, update rates, geofencing, spoofing detection, external interrupts, SBAS/D-GPS, and more.

The SparkFun ZED-F9R GPS pHAT also features an onboard rechargeable battery that powers the RTC on the ZED-F9R. This significantly reduces the time-to-first fix from a cold start (~24s) to a hot start (~2s). The battery can maintain RTC and GNSS orbit data without being connected to power for an extended period.

Please note that this product requires an antenna. Be sure to select a suitable U.FL antenna for your project.

The SparkFun Qwiic Connect System is an ecosystem of I2C sensors, actuators, shields and cables that facilitate faster and less error-prone prototyping. All Qwiic-enabled boards use a common 1mm pitch, 4-pin JST connector, which minimizes the amount of required PCB space and ensures correct connections thanks to its polarization.

The SparkFun ZED-F9R GPS pHAT's features include a Qwiic Connector, integrated U.FL connector for antenna use, concurrent reception of GPS, GLONASS, Galileo and BeiDou, 184-Channel GNSS Receiver, L1C/A and L2C bands reception, 0.01m accuracy with RTK, max navigation rate of up to 30Hz, time to first fix (Cold: 24s, Hot: 2s), operational limits (Max G: ≤4G, Max Altitude: 80km, Max Velocity: 500m/s), velocity accuracy: 0.5m/s, heading accuracy: 0.2 degrees, built-in accelerometer and gyroscope, time pulse accuracy: 30ns, voltage: 5V or 3.3V (all logic is 3.3V), current: ~85mA to ~130mA, and software configurability for geofencing, odometer, spoofing detection, external interrupt, pin control, low power mode, and more. It supports NMEA, UBX, and RTCM protocols over UART. The board dimensions are 65.00mm x 56.50 mm and it weighs 20.70g.

For more information, please refer to the available documents, including the schematic, eagle files, board dimensions, hookup guide, ZED-F9R datasheet, product summary, integration manual, u-blox interface description, u-blox ECCN, GPS Python Module, ReadtheDocs Documentation, GitHub Hardware Repo, and Raspberry Pi Resource Page.