Crate astrodyn_frames 

Reference frames, frame tree, and Earth/Mars/Moon rotation models.

Port of JEOD’s models/utils/ref_frames/ (the RefFrame tree that is the backbone of every coordinate system in JEOD) and models/environment/RNP/ (precession, nutation, polar motion). The crate is pure Rust with zero Bevy dependency.

Frame tree

• FrameTree, FrameNode, FrameId — an arena-based hierarchy that mirrors JEOD’s RefFrame parent/child links. Each node stores state relative to its parent (translation, velocity, orientation, angular velocity); relative states between arbitrary frames are computed by walking to the common ancestor and composing/negating states. The arena is a flat Vec with parallel Option<FrameId> parent pointers, which keeps lookups cache-friendly and avoids the pointer chasing of JEOD’s intrusive linked lists.
• RefFrameState, RefFrameStateTyped, RefFrameTrans, RefFrameRot — the per-node state structs (re-exported from ref_frame_state). Quaternions are JEOD-convention scalar-first, left-transformation, matching astrodyn_math::JeodQuat. Every node carries a required runtime identity (astrodyn_quantities::frame_descriptor::FrameUid) whose FrameClass is the runtime taxonomy (issue #664 removed the legacy 3-variant RefFrameKind).

Earth / Mars / Moon rotation

• rotation_j2000, precession_j2000, nutation_j2000, data_nutation_j2000 — Earth precession + IAU-1980 nutation series (the data_nutation_j2000 table is the 106-term series ported from JEOD’s RNP_J2000 data files).
• rotation_mars, rotation_moon — body-fixed rotation models for the Mars and Moon target bodies used by JEOD verification sims.

JEOD source: models/utils/ref_frames/ and models/environment/RNP/.

Example

Build a minimal frame tree with one root inertial frame and a planet-fixed child — every node carries a minted identity:

use astrodyn_frames::{FrameTree, RefFrameState};
use astrodyn_quantities::frame::{Ecef, RootInertial};
use astrodyn_quantities::frame_descriptor::FrameUid;

let mut tree = FrameTree::new();
let root = tree.add_root_typed::<RootInertial>("J2000".to_string());
let _ecef = tree.add_child_uid(
    root,
    FrameUid::of::<Ecef>(),
    "ECEF".to_string(),
    RefFrameState::default(),
    None,
);

// Both frames live in the arena, addressable by identity.
assert_eq!(tree.len(), 2);
assert_eq!(tree.find(&FrameUid::of::<Ecef>()), Some(_ecef));

Re-exports

pub use frame_storage::common_ancestor;

pub use frame_storage::compose_to_ancestor;

pub use frame_storage::compute_relative_state;

pub use frame_storage::FrameStorage;

pub use frame_tree::FrameId;

pub use frame_tree::FrameNode;

pub use frame_tree::FrameTree;

pub use frame_tree::FrameTreeError;

pub use orchestration::compute_relative_state_typed;

pub use orchestration::frame_origin;

pub use orchestration::frame_origin_typed;

pub use orchestration::sync_pfix_rotation;

pub use ref_frame_state::*;

Modules

data_nutation_j2000

IAU 1980 nutation coefficient tables for J2000.

frame_storage

Storage-agnostic frame-tree algorithms (Frame-Tree-ECS-Native § 7).

frame_tree

Arena-based frame tree: a faithful port of JEOD’s RefFrame hierarchy.

nutation_j2000

J2000 Nutation matrix and equation of equinoxes computation.

orchestration

Frame-tree orchestration helpers.

precession_j2000

J2000 Precession matrix computation.

ref_frame_state

Per-node frame state — the untyped storage form used by the crate::FrameTree arena and the typed sibling RefFrameStateTyped<P, C> used at the public API boundary.

rotation_j2000

J2000 GAST rotation and full RNP composition.

rotation_mars

Mars rotation model (IAU Pathfinder orientation).

rotation_moon

Moon rotation model (IAU 2009 simplified).