{
  "recommended_backend": "open3d_gicp",
  "selection_reason": "The two X estimates agree closely; Open3D has lower second-batch AX residual, better B loop closure, and lower first-batch auxiliary residual.",
  "coordinate_convention": "T_body_lidar maps raw LiDAR points into rear-axle body frame",
  "measured_extrinsic_used_as_initial": false,
  "second_batch_role": "estimation (dense RTK)",
  "first_batch_role": "auxiliary check only (sparse RTK)",
  "backend_difference": {
    "translation_m": 0.00181035475331947,
    "rotation_deg": 0.06312194455789993
  },
  "open3d_gicp": {
    "translation_m": [
      1.2978831677200011,
      -0.0030997734098957433,
      0.7217892226151688
    ],
    "rotation_rpy_deg_xyz": [
      -0.7572070226288585,
      1.1460424368859559,
      -0.8797812288284186
    ],
    "estimation_pairs": 66,
    "estimation_translation_rms_m": 0.10017183831403174,
    "estimation_rotation_rms_deg": 1.011529772202344,
    "bootstrap_std": [
      0.0020832827985508263,
      0.002063603632322515,
      0.001427746471392659,
      0.07576290622767821,
      0.06304875844333606,
      0.07843172452171372
    ],
    "initial_B_loop_closure": {
      "count": 106,
      "translation_rms_m": 0.020350848901853437,
      "translation_p95_m": 0.04464367942375473,
      "rotation_rms_deg": 0.2674546762953808,
      "rotation_p95_deg": 0.5761692075739222
    },
    "batch1_auxiliary_pairs": 41,
    "batch1_auxiliary_translation_rms_m": 0.06627076507951374,
    "batch1_auxiliary_rotation_rms_deg": 1.0783402768758907
  },
  "small_gicp": {
    "translation_m": [
      1.2996301155160686,
      -0.0035647011612625953,
      0.7218861757826791
    ],
    "rotation_rpy_deg_xyz": [
      -0.7871563544979889,
      1.1414557494228486,
      -0.9357571721886107
    ],
    "estimation_pairs": 80,
    "estimation_translation_rms_m": 0.11870623426762615,
    "estimation_rotation_rms_deg": 1.135091439337232,
    "bootstrap_std": [
      0.0017068433472663032,
      0.0019214288447692426,
      0.0013180801706094514,
      0.06849719260762097,
      0.05792635838163369,
      0.062093058432709465
    ],
    "initial_B_loop_closure": {
      "count": 252,
      "translation_rms_m": 0.06356464456110195,
      "translation_p95_m": 0.12253135158224471,
      "rotation_rms_deg": 0.7286536542725655,
      "rotation_p95_deg": 1.4911215410143956
    },
    "batch1_auxiliary_pairs": 36,
    "batch1_auxiliary_translation_rms_m": 0.07402020402512643,
    "batch1_auxiliary_rotation_rms_deg": 1.1492603033421918
  },
  "important_limit": "Backend agreement is strong, but AX rotation RMS remains about one degree. This is not a centimetre-grade absolute certification."
}