Collecting Data

App Startup

• App opens directly to the Home / Acquisition screen
• Unsupported Device screen shown if LiDAR is unavailable

Field Workflow

1. Mount the iPhone rigidly to the detector shaft
2. Connect detector audio via wired TRRS cable
3. (Optional) Tap Align to North and rotate phone flat toward geographic north
4. Adjust the red/blue sampling overlay to match coil footprint
5. Tap Start Collection to begin recording
6. Sweep normally left-to-right and right-to-left
7. Tap Add CTRL PTS at fixed reference features
8. Tap Stop Collection when finished

Align to North (Optional)

• Provides a rough yaw anchor only
• Outline turns green when accepted
• Final north alignment is done in post-processing

Control Points

• Create new sweep segments (L1, L2, etc.)
• Trigger LiDAR PLY snapshots
• Used later for alignment and georeferencing

What Is Recorded

• 2D sweep path (local LiDAR X,Y)
• Relative coil height
• Detector audio metrics
• Yaw, pitch, roll
• Timestamps
• LiDAR snapshots at control points

Note: Coil height is relative, not absolute.