支持 HI13/H32 主机 UTC 桥接对齐、多会话联合标定与 CAD 平移先验。

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

imu_lidar/time_offset.py

@@ -73,7 +73,10 @@ def _correlate_offset(
     y0, y1, y2 = peaks
     denom = y0 - 2 * y1 + y2
     if abs(denom) > 1e-12:
-        best_delta = float(best_delta + 0.5 * (y0 - y2) / denom * dt)
+        refined = float(best_delta + 0.5 * (y0 - y2) / denom * dt)
+        # Parabola can jump outside the searched window; keep it clamped.
+        if abs(refined) <= search_s + dt:
+            best_delta = refined
         best_peak = float(y1)
     return best_delta, best_peak
 
@@ -99,9 +102,12 @@ def estimate_time_offset(
     bias = np.zeros(3) if gyro_bias_rad_s is None else np.asarray(gyro_bias_rad_s, dtype=float)
     gyro = imu.gyro_rad_s - bias
 
-    stride = max(1, len(frames) // 20)
+    # Use short consecutive (or near-consecutive) pairs. A large stride (e.g.
+    # len//20) averages over many seconds and destroys |ω| correlation even when
+    # host/device clocks are already aligned.
+    stride = 1 if len(frames) < 80 else 2
     rotations, pair_times = estimate_frame_rotations(frames, stride=stride)
-    if len(rotations) < 4:
+    if len(rotations) < 8:
         rotations, pair_times = estimate_frame_rotations(frames, stride=1)
     if len(rotations) < 4:
         return TimeOffsetResult(0.0, 0.0, search_s, ("not enough LiDAR relative rotations",), False)