更新雷达相位中心 CAD 先验，并放宽主机桥接后的弱相关峰 δt 门控。

Co-authored-by: Cursor <cursoragent@cursor.com>

config/vehicle_hi13_h32_20260808.yaml

@@ -13,9 +13,10 @@ installation:
   installation_id: "20260808_priority_windows"
   installed_at: "2026-08-08"
   notes: >
-    HI13R4 + H32 DLogCapture. CAD mounts are origins vs rear axle center only
-    (translation). IMU axes confirmed on vehicle as HI13R4 manual §2.4 RFU
-    (X right, Y forward, Z up). LiDAR Cartesian assumed body-aligned.
+    HI13R4 + H32 DLogCapture. CAD mounts are origins vs rear axle center
+    (translation only). LiDAR phase-center Z = CAD dZ + 63.5 mm.
+    IMU axes: HI13R4 manual §2.4 RFU (X right, Y forward, Z up).
+    LiDAR Cartesian assumed body-aligned.
 
 sensors:
   imu:
@@ -25,7 +26,8 @@ sensors:
       axes: "X right, Y forward, Z up (RFU)"
       driver_axis_remapped: false
     mount_in_body:
-      # CAD 原点相对后轮轴中心（body: X fwd, Y left, Z up），单位 m
+      # CAD 图二：后轮轴中心 → IMU，单位 m（mm/1000）
+      # dX=2574.126255, dY=36.5, dZ=892.5
       translation_m: [2.574126255, 0.0365, 0.8925]
       # body <- imu : p_body = R_body_imu * p_imu
       # R_body_imu = [[0,1,0],[-1,0,0],[0,0,1]]  (fwd=imu_y, left=-imu_x, up=imu_z)
@@ -40,11 +42,13 @@ sensors:
       axes: "X forward, Y left, Z up (Cartesian metres in NPZ points)"
       driver_axis_remapped: false
     mount_in_body:
-      translation_m: [2.522276859, 0.000020526, 1.637499879]
+      # CAD 图一：后轮轴中心 → 雷达安装点，再加相位中心 +63.5 mm（仅 Z）
+      # dX=2522.276859, dY=0.020526, dZ=1637.499879+63.5=1700.999879
+      translation_m: [2.522276859, 0.000020526, 1.700999879]
       # 假设雷达系与车体 CAD 轴一致（导出 XYZ 已按此约定）
       rotation_matrix_body_lidar: [[1.0, 0.0, 0.0], [0.0, 1.0, 0.0], [0.0, 0.0, 1.0]]
       rotation_quaternion_xyzw: null
-      source: "CAD dX/dY/dZ vs rear axle; attitude assumed = body"
+      source: "CAD dX/dY/dZ + phase-center +63.5mm on Z; attitude assumed = body"
 
   rtk:
     frame_definition: ""
@@ -62,18 +66,18 @@ time:
 # t_IMU_lidar = R_IMU_body * t_body,  R_IMU_lidar = R_IMU_body * R_body_lidar
 derived_T_IMU_lidar_prior:
   R_IMU_lidar: [[0.0, -1.0, 0.0], [1.0, 0.0, 0.0], [0.0, 0.0, 1.0]]
-  t_IMU_lidar_m: [0.036479474, -0.051849396, 0.744999879]
-  t_lidar_from_imu_in_body_m: [-0.051849396, -0.036479474, 0.744999879]
+  t_IMU_lidar_m: [0.036479474, -0.051849396, 0.808499879]
+  t_lidar_from_imu_in_body_m: [-0.051849396, -0.036479474, 0.808499879]
   notes: >
     Rotation prior is ~90 deg yaw between body/lidar (X-fwd) and IMU RFU (Y-fwd).
-    Translation prior from CAD only; use for full_se3 / sanity, not as hard lock
-    for rotation_only.
+    Translation prior from CAD + LiDAR phase-center offset; use for full_se3 /
+    sanity, not as hard lock for rotation_only.
 
 initialization:
   translation_prior:
     enabled: true
     sigma_m: [0.05, 0.05, 0.05]
-    t_IMU_lidar_m: [0.036479474, -0.051849396, 0.744999879]
+    t_IMU_lidar_m: [0.036479474, -0.051849396, 0.808499879]
   rotation_prior:
     enabled: true
     sigma_deg: 15.0

imu_lidar/time_offset.py

@@ -137,8 +137,16 @@ def estimate_time_offset(
         f"LiDAR mean pair rotation {np.mean([rotation_angle_deg(r) for r in rotations]):.2f} deg"
     )
     notes.append(f"searched delta_t in ±{search_s:.3f}s by direct correlation")
-    ok = peak > 0.15
-    if not ok:
+    # Host-UTC-bridged sessions are already on one timeline; |ω| peak can stay
+    # weak even at the correct lag (ICP rate vs gyro scale). Accept near-zero δt.
+    near_zero = abs(float(delta)) <= min(0.05, 0.25 * float(search_s))
+    ok = peak > 0.15 or near_zero
+    if peak <= 0.15 and near_zero:
+        notes.append(
+            f"correlation peak weak ({peak:.3f}) but |delta_t|={abs(delta):.4f}s ~0; "
+            "accepting as already-aligned (e.g. host UTC bridge)"
+        )
+    elif not ok:
         notes.append("correlation peak is weak; check overlapping motion and axis units")
     return TimeOffsetResult(
         delta_t_s=delta,