Inputs
Use orbital mode for a quick estimate from altitude and elevation mask. Use custom mode if you already know typical visible time per satellite for your region.
Formula used
- Orbit period (circular): T = 2π √(a³/μ), where a = Rₑ + h.
- Visibility half-angle: ψ = arccos((Rₑ/(Rₑ+h)) · cos(Eₘᵢₙ)).
- Visible time (approx.): Tᵥᵢₛ = 2ψ / ωᵣₑₗ, with optional rotation: ωᵣᵉˡ ≈ n − ωₑ cos(latitude).
- Effective handover interval: Tₕ ≈ Tᵥᵢₛ / S, where S is satellites in view.
- Handover rate: Rateₕᵣ = 3600 / Tₕ.
- Disruption totals: Disruption = rate × disruption_per_handover.
How to use this calculator
- Select Orbital geometry unless you already know visible time.
- Enter altitude, elevation mask, and site latitude (if using orbital mode).
- Set satellites in view to reflect typical overlap at the site.
- Enter disruption per handover based on modem behavior or logs.
- Press Calculate to see handovers and expected downtime.
- Download CSV or PDF to share with your connectivity plan.
Example data table
These sample inputs illustrate typical planning scenarios for a remote construction site using a LEO link.
| Mode | Altitude (km) | Min elevation (°) | Latitude (°) | Sats in view | Disruption/hand (s) | Shift (h) | Expected use |
|---|---|---|---|---|---|---|---|
| Orbital | 550 | 25 | 30 | 2 | 1.2 | 10 | General field office and VoIP |
| Orbital | 1200 | 35 | 45 | 1.5 | 2.0 | 12 | Higher obstructions, fewer overlaps |
| Custom | — | — | — | 3 | 0.8 | 8 | Measured passes from site logs |
Why handover rate matters on job sites
LEO links can replace fragile microwave or temporary fiber during remote builds. Every handover is a brief routing and radio change, so frequent events can impact VoIP calls, machine telemetry, and cloud document sync. Estimating the handover interval helps you choose buffering settings, set acceptable latency targets, and plan fallback paths for critical crews. In cold starts, extra handovers can also lengthen VPN renegotiation and slow drawing downloads for foremen.
Interpreting satellites in view
The calculator treats overlap as simultaneous satellites available for a make-before-break transition. If you often see two or three satellites above your elevation mask, effective handovers occur less frequently because sessions can move gradually. Use monitoring logs or vendor dashboards to estimate realistic overlap during your work hours, not only at peak coverage. If overlap is low, consider dual terminals or bonded links.
Elevation masks and obstructions
Minimum elevation is a practical way to represent site blockage. Tall cranes, scaffold towers, nearby ridges, or urban canyons reduce low-angle visibility and shorten each usable pass. Raising the mask increases reliability but also increases handover rate. When uncertain, run two cases: a conservative high mask and an optimistic low mask to bracket performance. Measure blockage at noon and sunset too.
Using disruption seconds for risk
Disruption per handover converts events into downtime. Set it near zero for seamless buffering, or use measured dropouts from ping tests. Multiply by handovers per hour to estimate lost seconds, then compare to tolerances for dispatch voice, live video safety feeds, or automated equipment updates. For high-risk tasks, design redundancy rather than chasing perfect numbers.
Reporting results for stakeholders
Construction managers usually need simple metrics: handovers per hour, estimated downtime per shift, and the assumptions behind them. Export CSV for spreadsheets and cost models, and export PDF for permit packages or subcontractor briefs. Record the chosen elevation mask and overlap estimate so the plan can be updated when the site layout changes.
FAQs
What does handover interval mean?
It is the estimated time between satellite switches for your session. Short intervals mean more frequent transitions, which can increase brief stalls unless buffering, multi-path routing, or make-before-break overlap is available.
How do I pick satellites in view?
Use typical overlap you observe above your elevation mask during working hours. If dashboards show two satellites most of the time, enter 2. If overlap varies, use an average and test conservative cases.
Why does a higher elevation mask increase handovers?
A higher mask ignores low-angle passes that are often blocked by cranes or terrain. That shortens each usable pass, so the system must switch satellites more often to stay connected.
Should I enable Earth rotation adjustment?
Enable it for planning, especially away from the equator. It slightly refines relative motion used in the visibility estimate. If you already have measured visible time, use custom mode instead.
What value should I use for disruption seconds?
Start with 0.5–2.0 seconds if you have no measurements. If you can, measure packet loss or ping gaps during handovers and enter the typical gap your applications actually feel.
How can I reduce downtime in practice?
Improve line of sight by moving the terminal higher, reduce the elevation mask only if safe, use equipment that supports make-before-break, or deploy a secondary link for automatic failover during critical operations.