Galileo Notes: Ephemeris, Anomalies, I/NAV, SFRBX - Bert Hubert's writings
a day ago
- The author uses a Navilock NL-8012U with a u-blox 8 chipset, configuring it via u-center to enable Galileo and NMEA 4.1 for raw data.
- Galileo ephemeris parameters in semi-circle units require multiplication by π for calculations.
- Eccentric anomaly is computed through iteration (E = M + e * sin(E)), often in 10 iterations.
- True anomaly can be calculated using an approximation formula for near-circular orbits, with extra terms for elliptical orbits (e.g., e=0.162).
- Extracting ephemeris parameters from I/NAV messages involves parsing word types 1-4 with specific bit positions and sign handling.
- Coordinates in ECEF GTRF are derived using standard orbital mechanics, and elevation is calculated as 90° minus the angle between user and satellite vectors.