LEO Satellite Internet: Beam Steering & Handover

Constellation

Orbital altitude 550 km

Satellites in plane 6

Elevation mask 15°

Playback speed 120×

Ground Terminal Link

Elevation

0.0°

Beam steer (off zenith)

0.0°

Orbital period

– min

Handovers

How it works

A low-Earth-orbit broadband satellite (Starlink/OneWeb-class) is only useful to a ground terminal while it is above the local horizon by some margin. The terminal's phased-array antenna has no moving parts — it steers its beam electronically by delaying the signal at each element, so it can jump between satellites in microseconds:

elevation angle:  ε = arcsin( d̂ · ẑ )
beam steer angle: β = 90° − ε   (measured off local zenith ẑ)
where d̂ = unit vector from ground terminal to satellite

As the serving satellite sweeps overhead and its elevation ε drops toward the elevation mask (the minimum usable angle — low elevation means a long, atmosphere-heavy slant path and ground clutter), the terminal hands over to whichever visible satellite currently has the highest elevation. This is exactly the "make-before-break" handover strategy real LEO broadband constellations use to keep the link continuous.

Orbital period comes straight from Kepler's third law with Earth's real gravitational parameter:

T = 2π √(a³ / μ),   μ = 398,600.4 km³/s²,  a = R⊕ + h,  R⊕ = 6,371 km

Orbital altitude — sets the semi-major axis a and therefore the real orbital period (higher = slower pass, wider coverage footprint, fewer handovers).
Satellites in plane — how many spacecraft share this orbital track; more satellites means shorter gaps and a higher elevation mask can be maintained.
Elevation mask — the cutoff below which a satellite is considered unusable and the terminal must switch or go dark.
Playback speed — a real ~95-minute LEO pass compressed so handovers are visible in seconds; the physics (ε, β, T) stay real.

Serving satellite Idle satellite Ground terminal

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