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TODO: K-LD7 RADC Club Head Extraction

ARCHIVED DOCUMENT

This is a historical design or implementation note, kept as a record of why the code is shaped the way it is. It describes the project as of the date in its filename and is not a guide to follow — commands, paths, and constants may no longer match the code. See the Archive index for current alternatives.

Status: Not started Priority: High — needed for club path and angle of attack

What We Need

Two measurements from the K-LD7 RADC data that we currently don't extract:

1. Club Path (horizontal K-LD7)

The horizontal angle of the club head at impact. Combined with the ball's aim direction (which we already measure), this gives the club path relative to target — a key metric for understanding shot shape (draw/fade/push/pull).

2. Angle of Attack (vertical K-LD7)

The vertical angle of the club head at impact. This tells you whether the club is ascending or descending at impact — critical for driver optimization (hitting up) vs iron play (hitting down).

Approach

Same pipeline as ball extraction — the OPS243 already returns club_speed_mph on each shot. Use it exactly like we use ball_speed_mph:

  1. OPS club speed → compute aliased velocity bin via ball_bin_range_from_speed(club_speed_mph)
  2. Search RADC frames for energy at that bin (same find_impact_frames + CFAR)
  3. Phase interferometry at the club's velocity bin gives the angle

The main difference is timing — the club appears before the ball in the RADC buffer (club swing → impact → ball launch). The existing extract_launch_angle function may already find it if we pass club_speed_mph instead of ball_speed_mph. It might be as simple as calling the same function twice with different speeds.

Key Differences from Ball Extraction

Ball Club
Speed From OPS243 directly Estimated from OPS or smash factor
Timing After impact (ball in flight) Before impact (downswing)
Distance 3-5m (far range) 1-2m (close range)
RCS Small (golf ball) Large (club head)
Duration in beam 1-2 frames 1-2 frames
Velocity aliasing Yes (>62 mph) Sometimes (>62 mph club speed)

Files to Modify

  • src/openflight/kld7/radc.py — add extract_club_angle() function
  • src/openflight/kld7/tracker.py — add _extract_club_radc() method, wire into shot processing
  • src/openflight/server.py — pass club angle to Shot object (club_angle_deg field already exists)
  • tests/test_kld7.py — add tests with synthetic club head signals

Data Available for Development

Session logs with RADC data from both vertical and horizontal radars are in session_logs/. The RADC frames in the ring buffer contain the club head signal — it just needs to be found and extracted.

Use the capture script to collect RADC data with known club types: 

./scripts/capture_kld7_radc.py --port /dev/kld7_vertical --ops243-port /dev/ttyACM0 --duration 60 --club 7i
Then analyze offline with scripts/analyze_kld7_radc.py.