---
gsd_state_version: 1.0
milestone: v1.0
milestone_name: milestone
status: Phase 1 complete
last_updated: "2026-04-01T21:05:00Z"
progress:
  total_phases: 7
  completed_phases: 1
  total_plans: 3
  completed_plans: 3
---

# Project State

## Project Reference

See: .planning/PROJECT.md (updated 2026-04-01)

**Core value:** Flight controller must receive valid MAVLink GPS_INPUT at 5-10Hz with position accuracy ≤50m for 80% of frames — without this, the UAV cannot navigate in GPS-denied airspace.
**Current focus:** Phase 2 — Visual Odometry Pipeline

## Current Phase

**Phase:** 1 — ESKF Core (✓ Complete)
**Next action:** Run `/gsd:plan-phase 2` to plan Phase 2 (Visual Odometry Pipeline)

## Roadmap Summary

| Phase | Name | Status |
|-------|------|--------|
| 1 | ESKF Core | ✓ Complete |
| 2 | Visual Odometry Pipeline | Pending |
| 3 | Satellite Matching + GPR | Pending |
| 4 | MAVLink I/O | Pending |
| 5 | End-to-End Pipeline Wiring | Pending |
| 6 | Docker SITL Harness + CI | Pending |
| 7 | Accuracy Validation | Pending |

## Key Files

- `.planning/PROJECT.md` — project context and requirements
- `.planning/REQUIREMENTS.md` — 36 v1 requirements with traceability
- `.planning/ROADMAP.md` — 7-phase execution plan
- `.planning/codebase/` — codebase map (ARCHITECTURE, CONCERNS, STACK, etc.)
- `_docs/01_solution/solution.md` — authoritative architecture spec
- `_docs/00_problem/acceptance_criteria.md` — 43 test scenarios

## Session Notes

- Initialized 2026-04-01
- Brownfield: scaffold exists (~2800 lines), critical algorithms missing (ESKF, MAVLink, real TRT/cuVSLAM)
- cuVSLAM + TRT available only on Jetson; dev/CI uses OpenCV ORB stub + MockInferenceEngine
- Pipeline direction: top-down (API → ESKF → VO → satellite → GPS_INPUT)

## Phase 1 Execution Summary (2026-04-01)

**Status:** ✓ Complete — All 3 plans executed, 35 tests passing

**Deliverables:**
- `src/gps_denied/schemas/eskf.py` (68 lines) — ESKF data contracts (ConfidenceTier, ESKFState, ESKFConfig, IMUMeasurement)
- `src/gps_denied/core/eskf.py` (359 lines) — 15-state ESKF with IMU prediction, VO/satellite updates, confidence tiers
- `src/gps_denied/core/coordinates.py` (176 lines added) — Real K-matrix projection, ray-ground intersection, gps_to_pixel inverse
- `tests/test_eskf.py` (290 lines) — 18 ESKF unit tests
- `tests/test_coordinates.py` (+200 lines) — 17 coordinate chain tests

**Requirements Covered:** ESKF-01 through ESKF-06 (all 6 Phase 1 requirements)

**Commits:** 4 total (schemas, core ESKF, coordinates, tests, summaries)

**Verification:** pytest 35/35 passing (100% success)