Satellite Visibility Calculator
Calculate horizon slant range, ground coverage distance, central angle, and maximum pass duration for satellite ground station line-of-sight visibility.
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Inputs
Live
Math
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Related
Enter parameters and click Calculate to view results
Formula & Theory
d_slant = √(Rₑ² + (Rₑ+h)² - 2Rₑ(Rₑ+h)cos ψ), ψ = arccos[(Rₑ/(Rₑ+h)) cos θ] - θThis formula is used to calculate antenna parameters for satellite visibility calculator.
Overview
Use this satellite visibility calculator to determine line-of-sight visibility boundaries, maximum slant range, ground-track distance, and zenith pass duration for ground station satellite tracking.
Input Guide
Enter Satellite Altitude, Minimum Elevation Mask exactly in the units shown by this satellite visibility. Check the operating band, unit prefix, and decimal position before calculating; these are the inputs used by the formula.
- Satellite Altitude — use km.
- Minimum Elevation Mask — use °.
Output Guide
The results describe the calculated satellite visibility values for the inputs you entered. Check each value against the available space, selected components, feed system, and operating conditions before making a final design decision.
How This Calculator Works
The Satellite Visibility uses d_slant = √(Rₑ² + (Rₑ+h)² - 2Rₑ(Rₑ+h)cos ψ), ψ = arccos[(Rₑ/(Rₑ+h)) cos θ] - θ. Supply Satellite Altitude (km), Minimum Elevation Mask (°) in the displayed units, then use the calculated values as the first engineering target for this satellite communication design or analysis.
Design Notes
Theoretical line-of-sight extends to the geometric horizon (0° elevation angle). However, operational ground stations apply a minimum elevation mask (typically 5° to 10°) to avoid terrain obstacles, local atmospheric noise, and building obstruction.
Build and Tuning Notes
For LEO constellations (e.g., Starlink, ISS), a single overhead pass typically lasts 5 to 15 minutes max. At geostationary orbit (35,786 km), a satellite remains continuously visible within its hemisphere if the elevation angle remains above 0°.
Frequently Asked Questions
What is a ground station elevation mask angle?
An elevation mask angle is the minimum angle above the local horizontal plane required before a ground terminal attempts to track or communicate with a satellite, avoiding physical obstructions and ground RF noise.
How long can a LEO satellite remain visible during a single pass?
Depending on orbit altitude and elevation mask, a overhead zenith pass for LEO satellites (500–1,200 km) lasts between 6 and 15 minutes.
What is the sub-satellite point (nadir)?
The sub-satellite point is the position on Earth directly beneath the satellite where the satellite appears at a local elevation angle of exactly 90° (zenith).
Alex Warren
B.Sc. in Electrical & Electronic Engineering (EEE)
Alex specialises in antenna design and wave propagation. His expertise helps ensure these calculators present practical RF concepts, useful design estimates, and clear engineering guidance for students, HAM operators, and wireless professionals.