CubePilot Here4

The CubePilot Here4 is a dual-band RTK GNSS module for L1 and L5 with IMU, barometer and DroneCAN in a round puck housing, for medium-class multicopters. The maker is CubePilot of Australia. The receiver is a u-blox NEO-F9P, with an STM32H757 processor alongside.

The bands L1C/A, L5, E1B/C, E5a, B1I, B2a and GLONASS L1OF allow the ionosphere to be removed with two frequencies; GPS, GLONASS, Galileo, BeiDou, QZSS and SBAS are received. The manufacturer states 0.01 m + 1 ppm CEP, that is 1 cm at a radius containing half of the measurements, plus 1 mm per kilometre of distance from the base. Output runs at 20 Hz. The compass is an RM3100. Connection is through DroneCAN, UART or I2C; the module has two CAN ports and the firmware uses one. It measures 16 x 68 mm and weighs 60 g including cable.

A Drone-ID function is offered only by the Blue version. Anyone who must meet remote identification under EU law, which applies from class C1 and transmits the GNSS position, should therefore establish whether the aircraft meets it through this module, a separate module or from the factory. Geo-awareness also relies on the GNSS position. RTK improves the position but replaces none of these duties. Correction data come from a base, a radio link or NTRIP.

CubePilot has issued safety notices SB_0000008 and SB_0000010 for the Here4; they concern the magnetometer and a mandatory bootloader update. With a used module the bootloader version is therefore the first thing to check. Next come compass calibration at the mounting location, firmware matched to the autopilot version, and a look at the supplied cable.