PPC native replay from raw data

gnss ppc-native-replay rebuilds the selected native applications and generates a fresh baseline from PPC RINEX and IMU inputs. It does not require historical solver outputs. RTK, coupled RTK and fused antenna trajectories are scored separately; their names and populations are retained in the manifest.

This source-tree workflow complements the historical reproduce ppc-goal score-only lane. It does not reconstruct that lane's incompletely recorded solver configuration or claim its published selected-tier scores.

Run the evaluation

Configure a build from the current checkout first. Pass an explicit dataset root and a new output directory. The replay command builds its own targets, records the resulting binary hashes and fails if the source, binary or inputs change while it is running.

cmake -S . -B build -DCMAKE_BUILD_TYPE=Release -DGNSSPP_BUILD_PYTHON_BINDINGS=OFF
python3 apps/gnss.py ppc-native-replay --dataset-root /datasets/PPC-Dataset \
  --build-dir build --output-dir output/ppc-native-full

The default evaluates all six existing development runs with no epoch cap. It runs native processes sequentially. --paths rtk or --paths fusion limits the solver paths; --runs tokyo/run1 selects a development run. On Windows use --build-config Release, and add --runtime-dir <GTSAM DLL directory> when the configured build links GTSAM. This workflow does not require GTSAM.

For a bounded connectivity check:

python3 apps/gnss.py ppc-native-replay --dataset-root /datasets/PPC-Dataset \
  --build-dir build --runs tokyo/run1 --max-epochs 120 \
  --output-dir output/ppc-native-smoke

A positive epoch cap is explicitly labelled smoke. The fresh baseline uses low-cost, ratio 2.4, 18 subset drops, SNR weighting and disabled AR filtering. The fusion route additionally enables navi776-tc and uses the documented city-specific antenna lever arms. The actual arrays passed to each executable are the authoritative recipe, stored in manifest.json.

The manifest also records native algorithm environment knobs found in the solver/algorithm sources, including null for unset values. This captures environment-driven gate overrides as well as command-line options. Account and unrelated process environment variables are not collected.

Inspect and repeat

With both paths selected, the output contains source.tar.gz, build and native logs, saved CMake caches, RTK debug epochs, three POS streams per run, their score summaries, and a versioned manifest. In-tree output must be Git-ignored; use output/. The archive includes edited and untracked source files that are not ignored by Git. Extracting it into an empty directory reconstructs the source used by the run. Input data remain external and are identified by SHA-256.

state: passed proves the requested native runs and scoring commands succeeded and the recorded inputs stayed unchanged. It does not prove an accuracy target. Runtime is recorded per native process; coupled RTK and fused outputs share one fusion process, so their recorded runtime must not be summed twice. Reference CSVs are hashed and read by the offline scorer, never passed to the native inference command. These batch outputs do not certify online causality.

Repeat with a second empty directory and --compare-to:

python3 apps/gnss.py ppc-native-replay --dataset-root /datasets/PPC-Dataset \
  --build-dir build --output-dir output/ppc-native-repeat \
  --compare-to output/ppc-native-full/manifest.json

The comparison requires the same source contents, inputs, binaries, runtime libraries, selected runs and epoch cap. It checks every emitted POS data field, including positions and statuses, excluding comments and whitespace. A changed population or solution fails the command and is retained in the manifest. Source edits between the two runs require a new baseline.

The 2026-10-06 full verification at frozen commit b34cf3e7 generated all six runs and 18 streams twice. Every emitted POS numeric field, including status, matched exactly, and saved CMake settings matched. The repeatability record identifies both successful manifests and their source-content hash. The original replay schema predates the later algorithm-environment inventory; these runs used the shared parent environment without GNSS/PPC overrides. The source archives and full manifests remain in output/ppc-native-full-20261006/ and output/ppc-native-repeat-20261006/.