ERA_RATE
Defined in: mod.rs:83
const ERA_RATE: f64 = 7.2921151467069805E-5f64
Rate the Earth Rotation Angle advances at [rad per UT1 second].
The derivative of the ERA expression (IAU 2000 Resolution B1.8; IERS
Conventions 2010 Eq. 5.14): 2π × 1.00273781191135448 / 86400. Built from
the same ERA_TURNS_PER_UT1_DAY the angle itself is built from — one
crate-internal definition, so the two cannot drift apart.
This is the ERA step alone. The IAU 2006 rotation is W·R·Q, and its
full time derivative also carries the precession/nutation and polar-motion
rates Q̇/Ẇ plus a LOD correction, none of which this constant or
EarthFixedTransform(crate::earth::EarthFixedTransform) include. What it
gives is the Earth-spin term, which is the one that dominates: the omitted
rates are sub-µrad/s. Transporting velocities with OMEGA instead left
even that term disagreeing with the R it differentiates, by
1.47e-12 rad/s — 0.0103 mm/s at 7000 km.