SBG Systems Ellipse-D

The Ellipse-D from SBG Systems of France is a compact dual-antenna RTK GNSS/INS for navigation and motion capture on UAVs and robots. INS stands for inertial navigation system: it combines a satellite receiver with acceleration and rotation-rate sensors into a continuous solution of position, velocity and attitude.

The unit receives GPS, GLONASS, Galileo, BeiDou, QZSS and SBAS in two bands (L1C/A and L2C, E1 and E5b, L1OF and L2OF, B1 and B2). For RTK the manufacturer states 0.01 m + 1 ppm horizontally and 0.2 degrees for heading from two antennas; in post-processing with the Qinertia software it is 0.1 degrees. The navigation output runs at 200 Hz, and the inertial data at up to 1,000 Hz. Connection is through RS-232/422 (up to 2 Mbit/s, up to three ports) and CAN 2.0 A/B, plus PPS and event sync. The unit measures 46 x 45 x 32 mm, is supplied with 5 to 36 V and weighs 65 g.

The inertial sensors bridge short GNSS outages and deliver attitude and heading at a high rate that a pure GNSS receiver does not reach. That suits the unit to sensor platforms, gimbal control and georeferencing. It does not replace a flight controller but supplies navigation data to it or to a payload. The EU classes apply to the aircraft: from C1 upward geo-awareness and remote ID are mandatory, both resting on the GNSS position. Corrections come from a base, a radio link or NTRIP.

For selection it matters that the interfaces are serial: a flight controller with UART may need a level converter for RS-232/422. The distance and direction of the two antennas from the unit, the lever arm, are measured and entered; errors there shift the solution. The unit sits rigidly and with low vibration on the frame, and the firmware belongs to upkeep.