GNSS measurements, positioning and integrity (scenario kind family)

6 scenario kinds of the engine v0.38.0. Advisory: analysis output from a research and engineering tool, not type-approved navigation equipment and not a safety-of-life service. Every label here is the engine's or the verification matrix's; a kind is MODELLED unless the matrix says otherwise (how a label is earned: the README's Evidence section).

Topic pages: INTEGRITY, POSITIONING, ARAIM_REFERENCE, OSNMA. Run one: kshana scenarios/integrity-raim.toml. All families: KINDS.md.

integrity#

Snapshot / solution-separation / ARAIM RAIM with HPL/VPL and a Stanford diagram.

Required fields: mask_deg, sigma_uere_m, p_fa, p_md, al_h_m, al_v_m, time, user|user_site, constellation. Optional: sigma_ura_m, b_nom_m, constellations, seed, araim_dual, p_hmi, skyline.

Ledger: MODELLED 6 · VALIDATED 4. Full page, with the inputs, results, evidence and limitations: integrity.

kshana scenarios/integrity-raim.toml

gnss-sim#

Measurement-domain pseudorange simulation (Klobuchar iono, Saastamoinen/Niell tropo) + RAIM.

Required fields: seed, time, receiver, constellation. Optional: iono, tropo, mask_deg, noise_sigma_m, multipath_m, sat_clock_rms_m, uere_m, p_fa, p_md, alert_limit_h_m, alert_limit_v_m, skyline.

Ledger: VALIDATED. Full page, with the inputs, results, evidence and limitations: gnss-sim.

kshana scenarios/gnss-sim-raim.toml

pvt#

Real-observation single-point positioning: solve a receiver's position from a RINEX 3 observation file and a broadcast-navigation file (code pseudoranges, broadcast ephemeris, Klobuchar iono, Saastamoinen/Niell tropo), optionally validated against a surveyed coordinate.

Required fields: obs_rinex, nav_rinex. Optional: truth_ecef, apriori_ecef, mask_deg, dual_frequency.

Ledger: MODELLED. Full page, with the inputs, results, evidence and limitations: pvt.

kshana scenarios/pvt-abmf.toml

araim-reference-check#

Published ARAIM certification reference vectors: the engine's ARAIM horizontal and vertical protection levels run against the WG-C ARAIM Technical Subgroup's OWN worked numerical examples, at the tolerance (TOL_PL = 5e-2 m) those documents themselves state. Two vectors are committed as fixtures, each carrying its retrieval URL, retrieval date, source-file SHA-256 and page: the Reference Airborne Algorithm Description Document v3.1 (2019) Appendix D — self-consistent, and the acceptance vector — and the Milestone 3 Report (2016) Annex A section A.IX, the statement the research bibliographies cite. Every published input (the 10-satellite 2-constellation geometry matrix, the C_int and C_acc variance diagonals, b_nom, P_sat, P_const and the LPV-200 constant set) and every published output (VPL, HPL, EMT, sigma_v_acc, K_fa_3 and the two constellation-fault modes' sigma_3, sigma_ss_3 and b_3) is reported beside the engine's own number and their absolute difference. The protection-level equation is NOT re-solved here: the reference's mode list is handed to the engine's existing raim::araim_protection_level / araim_integrity_risk, so the bisection and the Gaussian-tail algebra under test are the engine's own; only the geometry, the sub-solutions, the detection thresholds and the published budget split are built for it. EXTERNALLY CHECKED against the 2019 vector: VPL 18.2926 m vs 18.3 m published, HPL 13.4063 m vs 13.45 m, EMT 7.2997 m vs 7.2998 m, sigma_v_acc 1.3694 m vs 1.3694 m, and all six published intermediates to within half a unit in their last printed decimal. The 2016 vector carries two internal defects the report states rather than hides — a sign typo in row 3 of G, and a K_fa_3 evaluated at 57 fault modes while the document states N_fault_max = 1 (12 modes) — so its geometry intermediates reproduce exactly while its protection levels are reported as measured discrepancies and excluded from the acceptance figure; the tolerance is never widened to absorb them. Every emitted numeric field carries a unit and a provenance class, and a transcribed figure is labelled published so it can never be mistaken for a computed one. SCOPE: only N_fault_max = 1 (single-satellite and single-constellation fault modes) is implemented, and a case whose priors require simultaneous multi-event fault subsets is REFUSED rather than silently truncated; fault detection, exclusion, the chi-square consistency check and the double-counting re-allocation step of the reference algorithm are out of scope. This reproduces a published reference algorithm's worked example — it is not a certification, an airworthiness artefact or an approval.

Required fields: none. Optional: vector.

Ledger: VALIDATED. Full page, with the inputs, results, evidence and limitations: araim-reference-check.

kshana scenarios/araim-reference-check.toml

space-weather#

Space-weather environment model: solar (F10.7/F10.7a) and geomagnetic (Kp, with the definitional Kp↔ap table) activity indices, the Jacchia-1971 exospheric temperature they drive (validated vs published solar-min/mean/max), and the Jacchia-1971 thermospheric neutral density at the diurnal-mean exospheric temperature against the activity-free static profile at a set of altitudes — the solar-cycle density dependence the static atmosphere omits. MODELLED: the density agrees with accelerometer-derived densities (TOLEOS CHAMP and GRACE) within a factor 2 at solar maximum but is about 1.7x too dense in the 2008 solar minimum.

Required fields: none. Optional: f107, f107a, kp, altitudes_km.

Ledger: MODELLED. Full page, with the inputs, results, evidence and limitations: space-weather.

kshana scenarios/space-weather.toml

realtime-frame-eop#

Real-time lunar frame / Earth-orientation prediction budget: P4 Table 1 (the frame-error consistency check — post-processed ~0.27 m ↔ ~0.010 ms and real-time ~15 m ↔ ~0.5 ms, each frame position expressed as its equivalent UT1 error via the L19 lever arm Δr = D_EM·ω⊕·ΔUT1) and Table 2 (measured UT1 prediction error vs horizon — the L18 curve read directly off the real IERS finals2000A series: the Bulletin A − Bulletin B final floor and the multi-day persistence-predictor error, each mapped to a Moon-frame position by L19), plus the L21 root-sum-square real-time frame-error budget (EOP + ephemeris + realisation floor). VALIDATED closed form (the L19 lever arm, ω⊕ cross-checked against the CIO Earth-rotation angle) and VALIDATED real data (the L18 curve off the real finals2000A rows); MODELLED are the lunar-relay OD covariance magnitudes and frame-realisation floor (representative allocations) and the persistence predictor (not IERS's operational Bulletin A algorithm). Not a certified real-time frame product.

Required fields: none. Optional: epoch, horizons_days, ephemeris_pos_sigma_m, ephemeris_vel_sigma_mps, latency_s, frame_realization_floor_m, delta_ut1_ms, delta_xp_mas, delta_yp_mas, eop_finals2000a, eop_finals2000a_later, frame_realization_tie_noise_m, operational_window_days, operational_min_cycle_fraction, operational_anchor_residual.

Ledger: MODELLED 1 · VALIDATED 2. Full page, with the inputs, results, evidence and limitations: realtime-frame-eop.

kshana scenarios/realtime-frame-eop.toml