u-blox ZED-X20P

The ZED-X20P from u-blox of Switzerland is a high-precision all-band GNSS module (17 x 22 x 2.4 mm) with support for RTK and PPP-RTK. It is classed for medium-class multicopters and intended as a building block that manufacturers fit into flight modules.

All-band means the receiver uses the signals of several bands at once. It handles GPS (L1C/A, L2C, L5), Galileo (E1, E5a, E6), BeiDou (B1I, B1C, B2a, B3I), QZSS (L1, L2C, L5), NavIC (L5; for L1 u-blox gives development as ongoing) and SBAS; GLONASS is not included. For RTK u-blox states 0.006 m + 1 ppm horizontally as CEP, that is 0.6 cm at a radius containing half of the measurements; for PPP-RTK via SPARTN below 0.06 m, and for the position without corrections 1.2 m. The rate is 25 Hz. Connection is through UART, SPI, I2C and USB. The module weighs 1.6 g and, according to the product summary, is in mass production.

Going without GLONASS affects the correction data: they must contain Galileo and BeiDou, otherwise the receiver uses only part of its satellites. A chip is not an aircraft; the duties of the EU drone regulation arise at the aircraft, where geo-awareness and remote identification (from class C1) rest on the GNSS position. RTK improves that position but replaces none of the duties. SPARTN is the format of PPP-RTK services, whose corrections come from a provider instead of from a nearby base.

When choosing a product with this chip, the planned correction source counts: base, NTRIP or SPARTN. The centimetre class depends on antenna, ground plane and distance from transmitters. Anyone choosing a ready-made flight module checks its firmware and the bands used.