Satellite Visibility Planner
Predict GNSS satellite visibility, passes and DOP for any location, date and elevation mask, using IGS broadcast ephemeris. See how many satellites are in view over time and find the best observation window for GPS, GLONASS, Galileo and BeiDou.
Visibility Planner FAQ
- What does the visibility planner do?
- Given a location, date and time window, it predicts which GNSS satellites are above your elevation mask over time, the total visible-satellite count, and the PDOP (position dilution of precision). It also lists individual satellite passes (rise, peak, set) so you can plan an observation session for the best geometry.
- Where does the orbit data come from?
- The planner downloads the IGS broadcast ephemeris (BRDC) for the selected UTC day and propagates each satellite orbit across your window. Broadcast ephemeris gives metre-to-decametre orbit accuracy — far more than enough for elevation, azimuth and DOP planning.
- What is PDOP and what is a good value?
- PDOP (Position Dilution of Precision) measures how satellite geometry amplifies ranging errors into position error. Lower is better: below 2 is excellent, 2–3 good, above 6 poor. The planner highlights the longest window where PDOP stays below 3.
- What is an elevation mask?
- The elevation mask is the minimum angle above the horizon at which a satellite is considered usable. Signals from low satellites travel through more atmosphere and suffer more multipath, so a mask of 10–15° is common. Satellites below the mask are excluded from the visible count and DOP.