SparkFun Electronics GPS-RTK2 Board (ZED-F9P)

The GPS-RTK2 board from SparkFun Electronics of the USA is a breakout board for the dual-band RTK module u-blox ZED-F9P. A breakout brings the connections of a chip module out to plugs and sockets so it can be used without a board of one's own. The board is classed for medium-class multicopters and suits both rover and base.

The receiver uses L1C/A and L2C and handles GPS, GLONASS, Galileo and BeiDou. For RTK SparkFun states 0.010 m horizontally and 2.5 m without RTK; that matches the u-blox chip value, 0.01 m + 1 ppm as CEP, that is 1 cm at a radius containing half of the measurements. The rate is 20 Hz in RTK operation and 25 Hz for position and raw data. Connection is through USB-C, two UARTs, I2C (Qwiic) and SPI. The board weighs 6.8 g.

At 6.8 g it is light enough to hardly burden the weight of small aircraft; antenna and cable come on top. The EU classes apply to the aircraft: from C1 upward geo-awareness and remote ID are mandatory, both resting on the GNSS position. As a base the board stands on a surveyed point and sends RTCM corrections to the rover on the aircraft. A compass is not part of the board; the orientation comes from the autopilot.

For selection it matters that a breakout is developer hardware: it has no housing, no strain relief and no protection from moisture. Electrostatic discharge and cable strain are the typical causes of failure, so the board belongs in a case and the leads are secured. The antenna with a ground plane and a clear view decides the result, and the F9P firmware is kept up to date.