Is this flight software?

No. SIDUS models are educational reimplementations. Cross-check before any flight decision.

Troposphere delay

Saastamoinen 1972 range correction from elevation and surface meteorology.

SIDUS educational calculator. Category satellite. Tags: geometry, GNSS, satellite. Pure SI. Not flight software.

d = 0.002277 sec z [p + (1255/T + 0.05)e - 1.16 tan^2 z]

Saastamoinen 1972 range correction

Atmospheric Correction for the Troposphere and Stratosphere in Radio Ranging of Satellites (J. Saastamoinen, AGU Geophysical Monograph 15 (1972)): Microwave range correction used by the troposphere-delay tool. The paper writes pressures in mbar; the tool converts pascals at the boundary.
Tropospheric Delay (ESA Navipedia): GNSS context for surface meteorological inputs and elevation limits of simple mapping functions. Not a validation of the 1972 equation.
Fundamentals of Astrodynamics and Applications (David A. Vallado): Standard reference for two-body, Lambert, maneuvers, and J2. Equations implemented independently in SIDUS.

Read /llms.txt or call https://sidus.tools/api/mcp. Open the interactive page for live SI inputs.