Satellite Laser Interlink Availability Margin Calculator
Translate optical link budgets into an availability margin by accounting for free-space loss, telescope gains, and engineered fade allowances.
Preliminary engineering tool. Validate mission-critical budgets with end-to-end optical link simulations and hardware-in-the-loop testing.
Examples
- Transmit -10 dBW, combined gain 220 dB, range 1,700 km, sensitivity -68 dBW, wavelength 1,550 nm, penalties 2.2 dB, fade 1.5 dB ⇒ Margin 11.51 dB (comfortable).
- Transmit -8 dBW, combined gain 205 dB, range 2,125 km, sensitivity -70 dBW, optional fields blank ⇒ Margin -1.42 dB (insufficient).
FAQ
Why combine transmit and receive gain?
Inter-satellite optical terminals are often specified with a composite gain. Summing the telescope apertures simplifies quick-look budgets; expand to separate terms if you need to evaluate aperture upgrades individually.
How should I set the fade allowance?
Use historical scintillation statistics and component aging models. High-latitude links or terminals near the terminator typically require larger fade margins than sun-synchronous daylight connections.
Can the calculator handle atmospheric relay scenarios?
For air-to-space relays, increase the atmospheric penalty to reflect absorption and weather outages, or replace it with site-specific fade distributions derived from ground station data.
Additional Information
- Result unit: decibels of remaining link margin relative to receiver sensitivity.
- Defaults assume a 1,550 nm laser with 2.2 dB of pointing/atmospheric penalties and 1.5 dB fade allowance.
- Status tags highlight whether the margin is comfortable (≥3 dB), tight (0–3 dB), or insufficient (<0 dB).