diff --git a/CLAUDE.md b/CLAUDE.md index 8a78ba4..101cf00 100644 --- a/CLAUDE.md +++ b/CLAUDE.md @@ -276,8 +276,82 @@ should be articulated in the descriptive text r for bearing to the right and l for bearing for the left; and t for higher range and y for smaller range. These controls should have slow movement for single stroke; but gradual for for holding key down. - - 5. Air Traffic PPI Scope - + + 5. Police Patrol Boat PPI + + This scope shows the radar display aboard a simulated Bellingham Police + Department patrol vessel making its routine waterfront patrol. Unlike all + other scopes in this exhibit the radar origin is not fixed — it moves with + the boat, making this a genuinely different operational experience. + + THE PATROL VESSEL AND ITS RADAR + The vessel carries a professional-grade open-array radar: 6 kW peak power, + 24-inch open array, ~1.9° horizontal beamwidth, mounted 3–4 m above the + waterline on a flybridge or radar arch. This is a working law-enforcement + vessel, not a recreational boat; the equipment reflects that. The narrower + beamwidth (vs a recreational radome's 4–6°) gives better azimuth resolution + and less sea clutter per range cell — important when searching for small + targets such as kayakers and stand-up paddleboards near the ferry lane. + + MAX RANGE: 2 miles. Range steps: 0.5 / 1 / 2 miles. + The patrol mission is close-in situational awareness. The tight range steps + let the officer zoom into the marina entrance, Whatcom Waterway, or the + ferry lane without switching to a different scope. + + RADAR HORIZON: ~4.3 nm at 3.5 m antenna height. Range is mission-limited + (2 miles) rather than horizon-limited. + + PATROL ROUTE (v1 — open water only) + The simulated vessel follows a continuous back-and-forth patrol of the + working waterfront at variable speed. Entry into Squalicum Marina and + Whatcom Waterway is deferred to a future version; v1 stays in open water + where the radar geometry is straightforward. + + Speed by zone: + Open waterfront / ferry lane: 10 knots + Near docks and breakwater: 4 knots + Route (loaded from data/patrol_route.json at startup): + Whatcom Waterway entrance → ferry terminal → Boulevard Park → + Taylor Dock → Community Boating Center → reverse and repeat + + SMALL TARGET SCENARIO — FERRY LANE + The Bellingham terminal serves Alaska Marine Highway ferries up to 400 ft. + The simulator places a scripted stand-up paddleboarder on a slow drift + across the ferry departure lane, plus random kayakers near the harbor mouth. + These are marginal radar targets: low RCS, no metal, minimal freeboard. + At 10 kt approach in light chop the paddleboarder may show as a faint + intermittent blip or vanish into sea clutter entirely. Visitors can try the + wave clutter filter (keys 5/6) and observe how suppressing clutter can also + suppress the very target they are looking for. This is the central teaching + moment of this scope: radar does not see everything. + + DISPLAY ORIENTATION + Default is North-up (000° at top). The k/j keys rotate the display offset. + Matching the offset to the boat's heading puts the bow at the top — Head-up + mode. The left panel labels the current mode and shows the heading marker, + a white dashed line from scope center toward the bow, drawn after all + phosphor content so it never decays. + + TERRAIN AND BREAKWATER CLUTTER + The concrete Squalicum Harbor outer breakwater is a strong radar return and + a significant shadow-caster. Everything behind the breakwater from the + patrol boat's point of view is shadowed — no return. The marina interior is + not visible from open water. This is realistic and visible on the scope. + Coastline, piers, and the ferry terminal structure also appear as clutter. + Shadow masks are pre-computed for patrol route waypoints by + terrain_preprocess and selected at runtime by nearest-waypoint lookup. + + Left panel status (below description text): + Zone: [plain text, e.g. "Ferry lane — open waterfront"] + Boat pos: XX.XXXX°N XXX.XXXX°W + Boat heading: XXX°T + Boat speed: X.X kt + Display mode: North-up (or Head-up) + Cursor range: X.X nm + Cursor brg: XXX°T + Max range: X.X mi + + 6. Air Traffic PPI Scope - Targets, range rings, and range ring text levels All are P7 phosphor. Immediate strike by the electron beam is blue. persistence is green/yellow. Targets, range rings, and range ring labels shall all @@ -326,7 +400,7 @@ should be articulated in the descriptive text These controls should have slow movement for single stroke; but gradual for for holding key down. - 6. Precision approach (PAR for short) + 7. Precision approach (PAR for short) PAR was developed in WWII and matured in the 1950s. With a fixed 10 mile range, it was controller who talked the pilot down verbally over radio, which means that the pilot does not have to rely on any equipment on the plane itself to help with landing. @@ -365,57 +439,62 @@ Threads 2,3, need mutex access to shared data that is read by thread 1. Thread 2 needs mutex access for shared data with thread 4, the simulator SUMMARY OF Controls: -● ┌─────┬─────────────────────────────────────┬───────┬──────────┬──────────────┬────────────┬─────────┬─────┐ - │ Key │ Function │ Intro │ Marine A │ Chain Home A │ Marine PPI │ ATC PPI │ PAR │ - ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼─────────┼─────┤ - │ s │ Advance to next scope │ ✓ │ ✓ │ ✓ │ ✓ │ ✓ │ ✓ │ - ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼─────────┼─────┤ - │ S │ back to previous scope │ ✓ │ ✓ │ ✓ │ ✓ │ ✓ │ ✓ │ - ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼─────────┼─────┤ - │ c │ Bearing clockwise │ │ ✓ │ │ │ │ │ - ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼─────────┼─────┤ - │ v │ Bearing counterclockwise │ │ ✓ │ │ │ │ │ - ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼─────────┼─────┤ - │ u │ Max range up │ │ ✓ │ │ ✓ │ ✓ │ │ - ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼─────────┼─────┤ - │ d │ Max range down │ │ ✓ │ │ ✓ │ ✓ │ │ - ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼─────────┼─────┤ - │ r │ Cursor bearing right │ │ │ │ ✓ │ ✓ │ │ - ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼─────────┼─────┤ - │ l │ Cursor bearing left │ │ │ │ ✓ │ ✓ │ │ - ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼─────────┼─────┤ - │ t │ Cursor range increase │ │ │ │ ✓ │ ✓ │ │ - ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼─────────┼─────┤ - │ y │ Cursor range decrease │ │ │ │ ✓ │ ✓ │ │ - ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼─────────┼─────┤ - │ k │ Antenna bearing offset right (boat) │ │ │ │ ✓ │ ✓ │ │ - ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼─────────┼─────┤ - │ j │ Antenna bearing offset left (boat) │ │ │ │ ✓ │ ✓ │ │ - ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼─────────┼─────┤ - │ [ │ Goniometer H/V switch │ │ │ ✓ │ │ │ │ - ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼─────────┼─────┤ - │ 9 │ Goniometer tune left │ │ │ ✓ │ │ │ │ - ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼─────────┼─────┤ - │ 0 │ Goniometer tune right │ │ │ ✓ │ │ │ │ - ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼─────────┼─────┤ - │ . │ Toggle PRF (25/12.5 Hz) │ │ │ ✓ │ │ │ │ - ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼─────────┼─────┤ - │ n │ Calibrator shrink │ │ │ ✓ │ │ │ │ - ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼─────────┼─────┤ - │ m │ Calibrator stretch │ │ │ ✓ │ │ │ │ - ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼─────────┼─────┤ - │ 1 │ Gain increase │ │ ✓ │ ✓ │ ✓ │ ✓ │ ✓ │ - ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼─────────┼─────┤ - │ 2 │ Gain decrease │ │ ✓ │ ✓ │ ✓ │ ✓ │ ✓ │ - ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼─────────┼─────┤ - │ 3 │ Rain clutter filter increase │ │ ✓ │ ✓ │ ✓ │ ✓ │ ✓ │ - ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼─────────┼─────┤ - │ 4 │ Rain clutter filter decrease │ │ ✓ │ ✓ │ ✓ │ ✓ │ ✓ │ - ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼─────────┼─────┤ - │ 5 │ Wave clutter filter increase │ │ ✓ │ ✓ │ ✓ │ │ │ - ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼─────────┼─────┤ - │ 6 │ Wave clutter filter decrease │ │ ✓ │ ✓ │ ✓ │ │ │ - └─────┴─────────────────────────────────────┴───────┴──────────┴──────────────┴────────────┴─────────┴─────┘ +● ┌─────┬─────────────────────────────────────┬───────┬──────────┬──────────────┬────────────┬──────────┬─────────┬─────┐ + │ Key │ Function │ Intro │ Marine A │ Chain Home A │ Marine PPI │ Boat PPI │ ATC PPI │ PAR │ + ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼──────────┼─────────┼─────┤ + │ s │ Advance to next scope │ ✓ │ ✓ │ ✓ │ ✓ │ ✓ │ ✓ │ ✓ │ + ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼──────────┼─────────┼─────┤ + │ S │ back to previous scope │ ✓ │ ✓ │ ✓ │ ✓ │ ✓ │ ✓ │ ✓ │ + ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼──────────┼─────────┼─────┤ + │ c │ Bearing clockwise │ │ ✓ │ │ │ │ │ │ + ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼──────────┼─────────┼─────┤ + │ v │ Bearing counterclockwise │ │ ✓ │ │ │ │ │ │ + ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼──────────┼─────────┼─────┤ + │ u │ Max range up │ │ ✓ │ │ ✓ │ ✓ │ ✓ │ │ + ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼──────────┼─────────┼─────┤ + │ d │ Max range down │ │ ✓ │ │ ✓ │ ✓ │ ✓ │ │ + ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼──────────┼─────────┼─────┤ + │ r │ Cursor bearing right │ │ │ │ ✓ │ ✓ │ ✓ │ │ + ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼──────────┼─────────┼─────┤ + │ l │ Cursor bearing left │ │ │ │ ✓ │ ✓ │ ✓ │ │ + ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼──────────┼─────────┼─────┤ + │ t │ Cursor range increase │ │ │ │ ✓ │ ✓ │ ✓ │ │ + ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼──────────┼─────────┼─────┤ + │ y │ Cursor range decrease │ │ │ │ ✓ │ ✓ │ ✓ │ │ + ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼──────────┼─────────┼─────┤ + │ k │ Display offset right (boat heading) │ │ │ │ ✓ │ ✓ │ │ │ + ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼──────────┼─────────┼─────┤ + │ j │ Display offset left (boat heading) │ │ │ │ ✓ │ ✓ │ │ │ + ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼──────────┼─────────┼─────┤ + │ [ │ Goniometer H/V switch │ │ │ ✓ │ │ │ │ │ + ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼──────────┼─────────┼─────┤ + │ 9 │ Goniometer tune left │ │ │ ✓ │ │ │ │ │ + ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼──────────┼─────────┼─────┤ + │ 0 │ Goniometer tune right │ │ │ ✓ │ │ │ │ │ + ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼──────────┼─────────┼─────┤ + │ . │ Toggle PRF (25/12.5 Hz) │ │ │ ✓ │ │ │ │ │ + ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼──────────┼─────────┼─────┤ + │ n │ Calibrator shrink │ │ │ ✓ │ │ │ │ │ + ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼──────────┼─────────┼─────┤ + │ m │ Calibrator stretch │ │ │ ✓ │ │ │ │ │ + ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼──────────┼─────────┼─────┤ + │ 1 │ Gain increase │ │ ✓ │ ✓ │ ✓ │ ✓ │ ✓ │ ✓ │ + ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼──────────┼─────────┼─────┤ + │ 2 │ Gain decrease │ │ ✓ │ ✓ │ ✓ │ ✓ │ ✓ │ ✓ │ + ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼──────────┼─────────┼─────┤ + │ 3 │ Rain clutter filter increase │ │ ✓ │ ✓ │ ✓ │ ✓ │ ✓ │ ✓ │ + ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼──────────┼─────────┼─────┤ + │ 4 │ Rain clutter filter decrease │ │ ✓ │ ✓ │ ✓ │ ✓ │ ✓ │ ✓ │ + ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼──────────┼─────────┼─────┤ + │ 5 │ Wave clutter filter increase │ │ ✓ │ ✓ │ ✓ │ ✓ │ │ │ + ├─────┼─────────────────────────────────────┼───────┼──────────┼──────────────┼────────────┼──────────┼─────────┼─────┤ + │ 6 │ Wave clutter filter decrease │ │ ✓ │ ✓ │ ✓ │ ✓ │ │ │ + └─────┴─────────────────────────────────────┴───────┴──────────┴──────────────┴────────────┴──────────┴─────────┴─────┘ + +Note: k/j (display bearing offset) are for marine PPI scopes only. The fixed ATC tower +at BLI has no heading offset need. On the fixed Marine PPI, k/j demonstrate North-up vs. +Head-up orientation as a teaching aid. On the Boat PPI, k/j are operationally meaningful: +zero offset = North-up (chart-style); offset matching boat heading = Head-up (bow at top). Table for general controls not yet implemented on the keyboard in the table above: @@ -521,6 +600,7 @@ Class Hierarchy: │ └── ChainHomeAScope ├── PPIScope (abstract) │ ├── MarinePPIScope + │ ├── BoatPPIScope │ └── ATCPPIScope └── PARScope @@ -570,6 +650,21 @@ MarinePPIScope : public PPIScope - Max range: 2, 4, 6 miles with correct ring sets - Keys: u (range up), d (range down) — this scope only +BoatPPIScope : public PPIScope + - Direct subclass of PPIScope (not of MarinePPIScope) + - Range steps: 0.5 / 1 / 2 miles; sweep time 4 s; phosphor P7 + - Radar parameters: 6 kW, 1.9° open array (distinct from 30 kW / 0.5° coastal) + - Radar origin = boat lat/lon from SharedRenderState, updated every sweep + - Variable patrol speed per route segment (loaded from data/patrol_route.json) + - Heading marker: white dashed line from scope center toward boat heading; + drawn after all phosphor content so it always appears fully bright + - Nearest pre-computed shadow mask selected each sweep via + TerrainMap::selectNearestBoatMask() — no runtime ray-marching + - Display mode indicator: "North-up" / "Head-up" based on offset vs heading + - Left panel status: zone text, lat/lon, boat heading, speed, display mode + - Keys: u/d (range 0.5/1/2), r/l (cursor bearing), t/y (cursor range), + k/j (display offset), 1/2 (gain), 3/4 (rain filter), 5/6 (wave filter) + ATCPPIScope : public PPIScope - Sweep time: 5 seconds - Max range: 5, 10, 15, 20 miles with correct ring sets @@ -606,6 +701,10 @@ File layout: scope_chain_home.h / scope_chain_home.cpp scope_ppi.h / scope_ppi.cpp — abstract PPIScope scope_marine_ppi.h / scope_marine_ppi.cpp + scope_boat_ppi.h / scope_boat_ppi.cpp — BoatPPIScope; police patrol boat; + moving radar origin; variable speed; + heading marker; display-mode tracking; + nearest-mask selection from TerrainMap scope_atc_ppi.h / scope_atc_ppi.cpp scope_par.h / scope_par.cpp phosphor.h / phosphor.cpp @@ -620,6 +719,11 @@ File layout: settings.h — all tunable constants; no .cpp needed + data/ + patrol_route.json — boat waypoints with lat/lon and speed per + segment; loaded by Simulator at startup; + not compiled in — edit without rebuild + shaders/ phosphor.vert / phosphor.frag — parameterized for P1 and P7 via uniforms graticule.vert / graticule.frag @@ -660,6 +764,30 @@ settings.h — tunable constants: - ATC terrain clutter suppressed flag (bool, default true) - ATC terrain shadow enabled flag (bool, default true) - LiDAR structure height threshold for man-made classification + - BOAT_PATROL_ROUTE_JSON: path to patrol route file (default "data/patrol_route.json") + Waypoints and per-segment speeds live in the JSON, not in settings.h, so + the route can be adjusted without recompiling + - BOAT_WAYPOINT_ARRIVAL_M: radius within which a waypoint is considered + reached, advancing to the next (default 50.0 m) + - BOAT_HEADING_TURN_RATE_DEG_S: maximum turn rate deg/s for heading + interpolation — realistic, not instantaneous (default 3.0) + - BOAT_HEADUP_TOLERANCE_DEG: offset within ±this value of boat heading + triggers "Head-up" label in left panel (default 5.0) + - BOAT_HEADING_MARKER_COLOR: RGB color of heading marker line (default white) + - BOAT_HEADING_MARKER_FRACTION: marker length as fraction of scope radius + (default 0.35) + - BOAT_HEADING_MARKER_DASH_PX: dash length in pixels (default 8) + - BOAT_HEADING_MARKER_GAP_PX: gap length in pixels (default 4) + - BOAT_CLUTTER_MASK_COUNT: number of pre-computed boat shadow masks (default 6) + - BOAT_MASK_SWITCH_THRESHOLD_M: minimum boat displacement from last selected + mask waypoint before a new mask is selected (default 500.0 m) + - METERS_PER_DEGREE: flat-earth scale factor for lat/lon → meters conversion + (111320.0, valid for 2 nm max range) + - Patrol boat radar parameters: BOAT_PEAK_POWER_W (6000), BOAT_FREQ_HZ, + BOAT_HORIZ_BEAMWIDTH_DEG (1.9), BOAT_VERT_BEAMWIDTH_DEG (20.0), + BOAT_ANTENNA_HEIGHT_M (3.5) + - Boat PPI range steps: BOAT_RANGE_STEPS[] = {0.5, 1.0, 2.0} miles, + BOAT_RANGE_STEP_COUNT = 3 ================================================================== @@ -688,7 +816,7 @@ Body: the time it takes for the echo to return, the radar calculates how far away the object is. Rotating the antenna builds a map of everything around it. - This exhibit features six radar displays. Explore each one at your own pace. + This exhibit features seven radar displays. Explore each one at your own pace. Press s at any time to jump to the next display — do not wait for the automatic 120-second advance. Press S (shift+s) to go back. @@ -810,25 +938,81 @@ PANEL 4 — MARINE PPI SCOPE Targets: AIS-equipped vessels and simulated traffic. Press s to advance. Press S to go back. Auto-advance in 120 seconds. - Any key press resets the timer. Next: ATC PPI → + Any key press resets the timer. Next: Marine PPI — Boat Scenario → - ┌──────┬────────────────────────────────────┐ - │ KEY │ FUNCTION │ - ├──────┼────────────────────────────────────┤ - │ s/S │ Next / previous scope │ - │ u/d │ Max range up / down (2, 4, 6 mi) │ - │ r/l │ Cursor bearing right / left │ - │ t/y │ Cursor range increase / decrease │ - │ k/j │ Antenna offset right / left │ - │ │ (boat heading correction — zero │ - │ │ means antenna faces True North) │ - │ 1/2 │ Gain increase / decrease │ - │ 3/4 │ Rain filter increase / decrease │ - │ 5/6 │ Wave filter increase / decrease │ - └──────┴────────────────────────────────────┘ + ┌──────┬────────────────────────────────────────────────┐ + │ KEY │ FUNCTION │ + ├──────┼────────────────────────────────────────────────┤ + │ s/S │ Next / previous scope │ + │ u/d │ Max range up / down (2, 4, 6 mi) │ + │ r/l │ Cursor bearing right / left │ + │ t/y │ Cursor range increase / decrease │ + │ k/j │ Display offset right / left │ + │ │ (zero = North-up; rotate to match heading │ + │ │ = Head-up — a teaching aid on fixed radar) │ + │ 1/2 │ Gain increase / decrease │ + │ 3/4 │ Rain filter increase / decrease │ + │ 5/6 │ Wave filter increase / decrease │ + └──────┴────────────────────────────────────────────────┘ ------------------------------------------------------------------ -PANEL 5 — AIR TRAFFIC CONTROL PPI SCOPE +PANEL 5 — POLICE PATROL BOAT PPI +------------------------------------------------------------------ + + This display is from the radar aboard a Bellingham Police Department + patrol vessel making its routine waterfront patrol. The scope center + is the boat — it moves with the patrol route, not fixed in the bay. + + THE RADAR IS DIFFERENT HERE + The patrol boat carries a professional 6-kilowatt open-array radar + with a 1.9-degree beam — narrower than a cheap boat radar, but wider + than the big 30-kilowatt coastal radar you saw two displays back. The + blips look noticeably fatter than on the coastal radar. The maximum + range here is 2 miles: the patrol mission is close-in harbor work, + not long-range scanning. + + THE FERRY LANE PROBLEM + The Bellingham terminal serves Alaska state ferries up to 400 feet + long. When a ferry departs, anyone in the departure lane — a kayaker, + a paddleboarder — must get clear. Watch the scope carefully: there + is a stand-up paddleboarder drifting slowly near the ferry lane. + Can you spot it? + + Stand-up paddleboards are very hard to see on radar. No metal, almost + no freeboard, small size — the radar echo is barely above the noise. + Try adjusting the wave clutter filter (keys 5 and 6). Turning it up + reduces the sea clutter that is hiding the target — but it may also + suppress the target itself. This trade-off is real. Radar does not + see everything. + + NORTH-UP AND HEAD-UP + By default the scope shows North-up: True North at the top, like a + chart. Press k or j to rotate the display. When the heading marker + (white dashed line) points straight up, you are in Head-up mode — + the bow is at the top. This is how most early marine radars worked. + + Location: Bellingham waterfront patrol, Bellingham Bay, WA. + Targets: AIS vessels, paddleboarder, random kayakers. + + Press s to advance. Press S to go back. Auto-advance in 120 seconds. + Any key press resets the timer. Next: ATC PPI → + + ┌──────┬────────────────────────────────────────────────┐ + │ KEY │ FUNCTION │ + ├──────┼────────────────────────────────────────────────┤ + │ s/S │ Next / previous scope │ + │ u/d │ Max range up / down (0.5, 1, 2 mi) │ + │ r/l │ Cursor bearing right / left │ + │ t/y │ Cursor range increase / decrease │ + │ k/j │ Display offset right / left │ + │ │ (0° = North-up; match heading = Head-up) │ + │ 1/2 │ Gain increase / decrease │ + │ 3/4 │ Rain filter increase / decrease │ + │ 5/6 │ Wave filter increase / decrease │ + └──────┴────────────────────────────────────────────────┘ + +------------------------------------------------------------------ +PANEL 6 — AIR TRAFFIC CONTROL PPI SCOPE ------------------------------------------------------------------ This is the Airport Surveillance Radar (ASR) display used by air traffic @@ -855,13 +1039,12 @@ PANEL 5 — AIR TRAFFIC CONTROL PPI SCOPE │ u/d │ Max range up / down (5, 10, 15, 20 mi) │ │ r/l │ Cursor bearing right / left │ │ t/y │ Cursor range increase / decrease │ - │ k/j │ Antenna offset right / left │ │ 1/2 │ Gain increase / decrease │ │ 3/4 │ Rain filter increase / decrease │ └──────┴──────────────────────────────────────────┘ ------------------------------------------------------------------ -PANEL 6 — PRECISION APPROACH RADAR (PAR) +PANEL 7 — PRECISION APPROACH RADAR (PAR) ------------------------------------------------------------------ The Precision Approach Radar was developed during World War 2 and refined @@ -1069,6 +1252,27 @@ RADAR PARAMETERS — PAR (X Band): Pulse width: short (high range resolution) PRF: high (~30 Hz alternating az/el) +RADAR PARAMETERS — PATROL BOAT (X Band): + Frequency: 9300–9500 MHz (X-band; treat same as marine for exhibit) + Peak power: 6 kW + Antenna type: Open array, 24-inch (610 mm) + Horizontal beamwidth: 1.9 degrees + Vertical beamwidth: 20 degrees + Antenna height: 3.5 m above waterline (flybridge or radar arch) + Radar horizon: ~4.3 nm to sea-level target + Operational max range: 2 miles (mission-limited, not horizon-limited) + + NOTE — beamwidth comparison: + Fixed coastal marine: 0.5° — sharp blips, high azimuth resolution + Police patrol boat: 1.9° — noticeably fatter blips; good exhibit contrast + Consumer radome: 4–6° — poorest resolution (not used in this exhibit) + + NOTE — small target detection in sea clutter: + The narrower 1.9° beam illuminates ~1/3 the sea surface area per range + cell compared to a 5° radome, improving signal-to-clutter ratio by ~5 dB. + Even so, a stand-up paddleboard (RCS ~0.1–0.5 m²) is marginal in any chop. + Detection is realistic only in near-calm conditions at ≤1 mile. + All radar parameters shall have corresponding constexpr constants in settings.h so they can be tuned without touching equation code. @@ -1175,10 +1379,31 @@ SHADOW / LINE-OF-SIGHT MASKING the offset as a rotation uniform and samples the polar texture at the offset angle. Zero CPU overhead; no shadow recomputation. - Future boat scenario (not in v1): - If the radar antenna physically moves to a new lat/lon, the shadow - mask would be recomputed on a background thread while the display - continues with the previous mask. + Boat PPI scope scenario: + When BoatPPIScope is active, SharedRenderState.boatModeActive is set + TRUE. LandClutter uses boatLatDeg / boatLonDeg as the polar grid origin + instead of the fixed marine platform position. + + Shadow mask selection: terrain_preprocess pre-computes BOAT_CLUTTER_MASK_COUNT + shadow masks for waypoints evenly spaced around the simulated route. + These are written as: + map/lidar_processed/shadow_boat_NNN.u8 — one file per boat mask waypoint + NNN = zero-padded index + At runtime, TerrainMap::selectNearestBoatMask() scans the BOAT_CLUTTER_MASK_COUNT + waypoints and returns the index whose position is nearest to the current boat + lat/lon (straight-line distance). The selected mask changes at most once per + 4-second sweep when the boat has moved more than BOAT_MASK_SWITCH_THRESHOLD_M + (default 500 m) from the last selected waypoint position. + + Since Bellingham Bay is open water, the major terrain shadowing features + (Chuckanut Mountain, Eliza Island, Lummi Island) are visible from most bay + positions. The nearest-mask approximation introduces negligible error within + the 500 m switching threshold. + + The terrain clutter shader receives the boat position offset as a translation + uniform (u_radarOffsetM, a vec2) in addition to the bearing offset rotation. + The shader adds this offset when sampling the polar texture so coastline + features appear at their correct positions relative to the moving radar. PER-SCOPE TERRAIN BEHAVIOR @@ -1219,11 +1444,14 @@ TERRAIN CLUTTER SHADER texture, and outputs P7-compatible phosphor color and alpha so terrain returns decay on the same timescale as target echoes. Uniforms: - u_bearingOffsetDeg — boat heading correction (default 0.0) + u_bearingOffsetDeg — display heading correction (default 0.0) + u_radarOffsetM — vec2 (dx_m, dy_m) from fixed marine platform origin + to current radar position; (0,0) for fixed scopes, + non-zero for Boat PPI as boat moves around the bay u_clutterSuppressed — bool; 1 = suppress (ATC mode) u_maxRangeM — current scope max range in meters u_clutterBrightness — TERRAIN_MARINE_CLUTTER_BRIGHTNESS scale - Used by MarinePPIScope and ATCPPIScope. + Used by MarinePPIScope, BoatPPIScope, and ATCPPIScope. ================================================================== @@ -1257,15 +1485,23 @@ PIPELINE (runs in order) 7. Material classification: Load S-57 ENC (US5WA45M.000) via GDAL/OGR. Apply classification rules described in TERRAIN section above. - 8. Compute shadow mask for marine platform and ATC tower using radial - elevation-angle march along each azimuth bearing. + 8. Compute shadow masks using radial elevation-angle march along each + azimuth bearing for each of the following radar positions: + - Fixed marine platform (lat 48.7436, lon -122.5647) + - ATC tower at BLI + - BOAT_CLUTTER_MASK_COUNT boat waypoints from BOAT_SIM_WAYPOINTS[] + All shadow masks use the same algorithm; only the origin differs. 9. Write to map/lidar_processed/: - elevation.f32 float32 row-major grid, meters, WGS84 - material.u8 uint8 per cell (0=water 1=soil 2=rock 3=concrete) - shadow_marine.u8 uint8 visibility mask for marine radar - shadow_atc.u8 uint8 visibility mask for ATC radar - terrain_meta.json grid dimensions, lat/lon origin, cell size, - source file checksums, processing date + elevation.f32 float32 row-major grid, meters, WGS84 + material.u8 uint8 per cell (0=water 1=soil 2=rock 3=concrete) + shadow_marine.u8 uint8 visibility mask for marine radar + shadow_atc.u8 uint8 visibility mask for ATC radar + shadow_boat_000.u8 … + shadow_boat_NNN.u8 uint8 visibility masks for boat waypoints; + NNN = zero-padded waypoint index + terrain_meta.json grid dimensions, lat/lon origin, cell size, + source file checksums, processing date, + boat mask waypoint lat/lon list RUNTIME VALIDATION TerrainMap reads terrain_meta.json at startup and compares the stored @@ -1276,18 +1512,188 @@ RUNTIME VALIDATION The exhibit does not crash; it runs with the old grid. OUTPUT FILES (map/lidar_processed/) - elevation.f32 — float32 elevation grid - material.u8 — uint8 material classification grid - shadow_marine.u8 — uint8 line-of-sight mask, marine radar - shadow_atc.u8 — uint8 line-of-sight mask, ATC radar - terrain_meta.json — metadata and provenance record + elevation.f32 — float32 elevation grid + material.u8 — uint8 material classification grid + shadow_marine.u8 — uint8 line-of-sight mask, marine radar + shadow_atc.u8 — uint8 line-of-sight mask, ATC radar + shadow_boat_000.u8 … — uint8 line-of-sight masks for boat waypoints + shadow_boat_NNN.u8 (BOAT_CLUTTER_MASK_COUNT files total) + terrain_meta.json — metadata, provenance record, and boat mask + waypoint lat/lon list used for nearest-mask lookup - These five files are the only terrain inputs at runtime. + These files are the only terrain inputs at runtime. The raw zip archives in map/lidar_raw/ are never opened by the exhibit binary. ================================================================== +BOAT SCENARIO + +================================================================== + +The boat scenario (scope 5 — Police Patrol Boat PPI) simulates a Bellingham +Police Department patrol vessel making its waterfront patrol. The radar is a +6 kW professional open-array unit (1.9° beamwidth), not the same hardware as +the fixed coastal marine radar. The radar origin moves with the boat every sweep. + +PATROL ROUTE FILE — data/patrol_route.json + + Loaded by the Simulator at startup. Not compiled in — the route can be + refined without a rebuild. Format (approximate): + + { + "waypoints": [ + { "lat": 48.7530, "lon": -122.5150, "speed_kt": 10.0, + "zone": "Ferry lane — open waterfront" }, + { "lat": 48.7480, "lon": -122.5050, "speed_kt": 4.0, + "zone": "Near Squalicum breakwater" }, + { "lat": 48.7460, "lon": -122.5120, "speed_kt": 10.0, + "zone": "Open waterfront west" }, + { "lat": 48.7380, "lon": -122.5200, "speed_kt": 10.0, + "zone": "Boulevard Park approach" }, + { "lat": 48.7340, "lon": -122.5150, "speed_kt": 4.0, + "zone": "Taylor Dock area" }, + { "lat": 48.7320, "lon": -122.5050, "speed_kt": 4.0, + "zone": "Community Boating Center" } + ], + "loop": "reverse" + } + + "loop": "reverse" means the boat reaches the last waypoint then reverses + direction back through the list — a back-and-forth patrol, not a closed loop. + All coordinates are open water; marina and Whatcom Waterway entry deferred. + Adjust lat/lon values to keep the vessel in navigable water once the ENC + coastline is loaded. Values above are starting approximations. + +BOAT NAVIGATION SIMULATION (Simulator, Thread 4) + + The Simulator maintains a BoatNavigator sub-object that loads the JSON route + at startup and advances the vessel each time TrafficCop polls. Data returned + to TrafficCop alongside the regular target list: + boat_lat_deg — current latitude (degrees WGS84) + boat_lon_deg — current longitude (degrees WGS84) + boat_heading_deg — current true heading (degrees, 0 = north) + boat_speed_kts — current speed from active waypoint segment + boat_zone_str — zone label string for left panel display + + TrafficCop writes these to SharedRenderState under Mutex A. + Thread 1 reads them every frame when BoatPPIScope is active. + + Navigation algorithm (runs in Simulator::poll(), Thread 4): + 1. Compute great-circle bearing from current position to next waypoint. + 2. Rotate boatHeadingDeg toward that bearing at up to + BOAT_HEADING_TURN_RATE_DEG_S per elapsed second (clamped). + 3. Advance position along current heading at the current segment speed_kt. + 4. If distance to next waypoint < BOAT_WAYPOINT_ARRIVAL_M, advance index. + On reverse-loop: flip traversal direction at each end. + 5. Store updated state in BoatNavigator; return to TrafficCop on poll. + +SIMULATED SMALL TARGETS + + The Simulator generates two categories of small targets for the patrol scope: + + Scripted paddleboarder: + A single stand-up paddleboarder drifts slowly across the ferry departure + lane on a fixed looping path (~0.5 kt, random drift added). RCS set to + BOAT_SUP_RCS_M2 (default 0.2 m²). This target also appears on the fixed + Marine PPI scope (same Bellingham Bay coverage area, same target pipeline). + + Random kayakers: + BOAT_RANDOM_KAYAK_COUNT (default 2) kayaks wander within a defined zone + near the ferry terminal and harbor mouth. RCS set to BOAT_KAYAK_RCS_M2 + (default 0.4 m² — slightly larger than SUP due to hull and occupant). + Random targets also appear on the fixed Marine PPI. + + These use the same radar equation path as all other targets; the low RCS + values naturally produce faint, intermittent blips in any sea state, which + is the exhibit's intended behavior. No special-casing required. + + Settings.h additions for small targets: + BOAT_SUP_RCS_M2 0.2 — stand-up paddleboard + paddler RCS (m²) + BOAT_KAYAK_RCS_M2 0.4 — kayak + occupant RCS (m²) + BOAT_RANDOM_KAYAK_COUNT 2 — number of random kayak targets + BOAT_KAYAK_ZONE_LAT/LON — bounding box for random kayak positions + +SHARED STATE ADDITIONS + + SharedRenderState new fields (all under Mutex A): + float boatLatDeg = 0.0f (set from JSON WP0 at startup) + float boatLonDeg = 0.0f + float boatHeadingDeg = 0.0f + float boatSpeedKts = 0.0f + char boatZone[64] = "" — zone label, copied from JSON waypoint + bool boatModeActive = false — set TRUE by ScopeManager when BoatPPIScope + active, FALSE for all other scopes + +TARGET PROJECTION FOR MOVING RADAR ORIGIN + + For fixed scopes, target positions are projected from a known constant origin. + For the Boat PPI, TrafficCop recalculates each target's polar coordinates + relative to the boat's current position after every poll. + + Flat-earth projection (adequate for 2 nm max range): + dx_m = (target_lon − boat_lon) × cos(boat_lat × π/180) × METERS_PER_DEGREE + dy_m = (target_lat − boat_lat) × METERS_PER_DEGREE + range_m = sqrt(dx_m² + dy_m²) + bearing_deg = atan2(dx_m, dy_m) × 180/π (adjusted to 0–360, CW from north) + + METERS_PER_DEGREE = 111320.0 (constexpr in settings.h). + Result (range_m, bearing_deg, brightness) stored in TargetBuffer under Mutex B. + +HEADING MARKER RENDERING + + BoatPPIScope::renderHeadingMarker() runs inside render() after all phosphor + content, using the graticule shader so the line never decays. + + Geometry: dashed line from scope center to + center + BOAT_HEADING_MARKER_FRACTION × scope_radius + in the direction (boatHeadingDeg + bearingOffsetDeg). + Color: BOAT_HEADING_MARKER_COLOR (default white). + Dash/gap: BOAT_HEADING_MARKER_DASH_PX / BOAT_HEADING_MARKER_GAP_PX. + +DISPLAY MODE LOGIC + + Every frame, BoatPPIScope computes: + float diff = fabs(fmod(bearingOffsetDeg − boatHeadingDeg + 540.0f, 360.0f) − 180.0f) + mode = (diff <= BOAT_HEADUP_TOLERANCE_DEG) ? "Head-up" : "North-up" + Rendered as white text in the left-panel status area. + +TERRAIN CLUTTER AND BREAKWATER SHADOWS + + See SHADOW / LINE-OF-SIGHT MASKING → Boat PPI scope scenario for the + mask-selection algorithm and shadow_boat_NNN.u8 file set. + + The Squalicum Harbor outer breakwater is a significant shadow-caster. + From any open-water patrol position the interior of the marina basin is + shadowed — nothing behind the breakwater is visible. This is realistic + and is visible on the scope as a sharp shadow arc on the far side of the + breakwater return. + + At the start of each 4-second sweep, BoatPPIScope::updateLandClutter() calls: + 1. TerrainMap::selectNearestBoatMask(boatLatDeg, boatLonDeg) + 2. LandClutter::generateForBoat(boatLatDeg, boatLonDeg, maskIndex) + 3. Upload new polar clutter texture to GPU. + If the mask index is unchanged from the previous sweep, steps 2–3 are skipped. + + Terrain clutter shader receives: + u_radarOffsetM = vec2( + (boatLon − MARINE_PLATFORM_LON) × cos(boatLat × π/180) × METERS_PER_DEGREE, + (boatLat − MARINE_PLATFORM_LAT) × METERS_PER_DEGREE) + +V1 GEOMETRY SCOPE (open water only — marina deferred) + + Vector features needed from NOAA ENC 18424 for the v1 patrol route: + - Outer shoreline of Bellingham Bay + - Squalicum Harbor outer breakwater (solid, strong return, shadow-caster) + - Ferry terminal structure (Bellingham Cruise Terminal area) + - Taylor Dock pier outline (weak return — wood, but pilings visible) + - Boulevard Park shoreline + Internal marina dock fingers, Whatcom Waterway channel walls, and Georgia + Pacific / Waterfront District structures are deferred until the patrol + route is extended into those areas in a future version. + +================================================================== + FILE LAYOUT (COMPLETE — including additions) ================================================================== @@ -1302,6 +1708,7 @@ src/ scope_chain_home.h / scope_chain_home.cpp scope_ppi.h / scope_ppi.cpp scope_marine_ppi.h / scope_marine_ppi.cpp + scope_boat_ppi.h / scope_boat_ppi.cpp scope_atc_ppi.h / scope_atc_ppi.cpp scope_par.h / scope_par.cpp phosphor.h / phosphor.cpp @@ -1338,4 +1745,5 @@ shaders/ bloom.vert / bloom.frag — FBO bloom post-processing terrain_clutter.vert / terrain_clutter.frag — polar clutter texture overlay on PPI; P7-compatible decay; - bearing offset rotation uniform + bearing offset rotation uniform; + u_radarOffsetM vec2 for boat origin diff --git a/additions b/additions deleted file mode 100644 index 1cef301..0000000 --- a/additions +++ /dev/null @@ -1,228 +0,0 @@ -================================================================== -ADDITION: BOAT RADAR — BELLINGHAM POLICE PATROL BOAT -================================================================== - -I want to add a radar scope showing the view from a marine radar -mounted on a Bellingham Police Department patrol boat. The boat -is on a continuous back-and-forth patrol of the working waterfront. - -PATROL ROUTE: - Police boats do patrol inside Squalicum Marina (theft, vandalism, - welfare checks) and inside Whatcom Waterway (commercial port - security). They do not rely on seeing over the breakwater -- - the concrete breakwater shadows the inner basin. - - Speed varies by zone: - Open waterfront: 10 knots - Whatcom Waterway: 3-5 knots (narrow, industrial) - Inside marina: 3-4 knots (displacement speed, no wake) - - Proposed full route (continuous, reversing at each end): - Whatcom Waterway entrance - -> slow to 4 knots, transit Whatcom Waterway - -> exit to bay, accelerate to 10 knots - -> Squalicum Marina outer breakwater entrance - -> slow to 3-4 knots, tour inner marina basin - -> exit marina, accelerate to 10 knots - -> west along waterfront - -> Boulevard Park - -> Taylor Dock - -> Community Boating Center - -> reverse and repeat - - INSIDE MARINA -- RADAR CLUTTER NOTE: - At 2-3 m antenna height inside a marina full of sailboat masts, - the radar picture will be heavily cluttered with mast returns, - appearing as a dense ring around the boat. This is realistic and - is a good exhibit teaching moment -- visitors can use the sea/wave - clutter filter (already designed) to try to suppress it. The boat - radar's wide beamwidth (4-6 deg) makes the clutter worse than the - big coastal radar would show. - -PATROL SPEED: - Approximately 10 knots. - - 10 knots is reasonable -- typical working-waterfront patrol speed - is 8-12 knots, fast enough to respond quickly but slow enough to - observe traffic and avoid wake damage near the docks. - -WHAT THIS MEANS FOR THE DISPLAY: - Unlike all the other radars in this exhibit, the radar origin is - not fixed. It moves with the boat along the patrol route. The - radar antenna is on the boat, so the PPI scope center tracks the - boat's position. - - The boat also changes heading as it follows the shoreline, which - means the bearing offset (already implemented as the k/j keys on - the marine PPI) will be continuously updated by the simulator as - the boat turns -- the operator does not manually drive the boat. - - The boat's heading at any point along the route determines the - antenna offset so that True North stays at the top of the scope. - -SIMULATOR ARCHITECTURE: - The patrol boat position is the radar PLATFORM, not a target. - It should be managed by the existing Simulator (Thread 4) as a - special PatrolPlatform object alongside the target list -- NOT a - separate simulator thread, and NOT built into the scope/rendering - code (Thread 1). - - The TrafficCop (Thread 2) already polls the Simulator each sweep. - It will also retrieve the current platform lat/lon and heading at - the same poll and write them to SharedRenderState under Mutex A. - Thread 1 reads platform position and heading to set the PPI scope - center point and bearing offset before rendering each frame. - - The patrol route is a sequence of lat/lon waypoints with speed - per segment. The Simulator interpolates position between waypoints - using elapsed time and the segment speed. - -DECISIONS: - 1. SCOPE CLASS: New BoatPPIScope, a subclass of PPIScope directly - (not a subclass of MarinePPIScope). Same controls as MarinePPIScope. - Moving origin is specific to this class. - - 2. WAYPOINTS: JSON data file, e.g. data/patrol_route.json. - Loaded at startup by the Simulator. Each entry has lat/lon and - speed for that segment. settings.h stays as tunable constants only. - - 3. LEFT PANEL: Both -- a plain text zone description (e.g. - "Currently: Open waterfront, heading west") AND a numeric - lat/lon readout below it. Visitor-friendly text plus precise data. - - 4. SIMULATED SMALL TARGETS: Both scripted and random. - - Scripted: a paddleboarder drifts slowly across the ferry lane - on a fixed loop (dramatic, repeatable, good for exhibit) - - Random: additional kayakers/small boats wander within a defined - zone near the ferry terminal and harbor mouth - - These small targets also appear on the fixed MARINE PPI scope - (same Bellingham Bay coverage area, same target pipeline) - - 5. SCOPE ORDER: Boat PPI goes immediately after Marine PPI. - New sequence: Intro -> Marine A -> Chain Home A -> Marine PPI - -> Boat PPI -> ATC PPI -> PAR -> (back to Intro) - - 6. MARINA AND WHATCOM WATERWAY: Deferred. The patrol route for v1 - stays in open water only. The boat does NOT enter Squalicum Marina - or Whatcom Waterway in the first implementation. Those can be - added in a later version once the shoreline geometry problem - is solved (see LIDAR/CHART NOTE below). - -LIDAR AND SHORELINE GEOMETRY NOTE: - - The marina, breakwater, Whatcom Waterway, and Georgia Pacific site - all require accurate geometry to simulate correctly -- both as radar - return sources and as shadow-casters. - - TWO DATA SOURCES: - - 1. NOAA Electronic Navigational Chart 18424 (Bellingham Bay) - Free vector download from charts.noaa.gov (ENC format). - Already clean vector polygons: breakwater, piers, channel edges, - ferry terminal, dock outlines. Best starting point -- no point - cloud processing required. - - 2. Washington State LIDAR Portal (lidarportal.dnr.wa.gov) - Free LIDAR point cloud downloads for Whatcom County. - 0.5-1 meter horizontal resolution. Captures individual pilings, - building edges, breakwater detail, Georgia Pacific site remnants. - Use this when finer detail is needed (inside marina, Whatcom - Waterway structures). Requires offline processing to extract - obstruction polygons before use in the simulation. - - GEORGIA PACIFIC SITE: - Most of the old GP pulp mill has been demolished. The area is - now the Bellingham Waterfront District (partially built). LIDAR - or ENC data will show whatever was on-site at survey time. For - the exhibit this is acceptable -- it is a patrol scenario, - not a live chart. - - HOW GEOMETRY FEEDS INTO THE SIMULATION: - Shoreline and obstruction data is processed ONCE offline into - a set of vector polygons representing hard radar-reflective - features. These are loaded at Thread 1 startup as a static VBO. - Read-only after load -- no mutex required (already noted in - the design). The radar sweep computes returns from these - polygons the same way it handles vessel targets. - - RADAR SHADOW ZONES: - The breakwater does not just produce a return -- it shadows - everything behind it. To simulate this correctly, the sweep - must raycast from the current radar position, find the first - intersection with each obstruction polygon, and mark everything - beyond that intersection as shadowed (no return). This is a - per-sweep raycast operation, implementable CPU-side each sweep - or in a compute shader. Shadow simulation is required even for - the v1 open-water-only route, because the breakwater shadow - is clearly visible from outside. - - V1 GEOMETRY SCOPE (open water only -- marina deferred): - Only these features are needed for the first version: - - Outer shoreline of Bellingham Bay (simple polygon) - - Squalicum Harbor breakwater (solid obstruction, shadow-caster) - - Ferry terminal structure - - Taylor Dock pier outline (weak return -- wood, but pilings show) - - Boulevard Park shoreline - NOAA ENC 18424 provides all of these in vector form. - Internal marina dock fingers and Whatcom Waterway structures - are deferred until the boat patrol route enters those areas. - - 4. The radar hardware spec for the boat radar is DIFFERENT from - the fixed coastal marine radar. Typical police/patrol boat radar: - - Frequency: 9.3 - 9.5 GHz (X-band, same band, slightly - different frequency -- treat as same for exhibit) - Peak power: 2 kW to 4 kW (NOT the 30 kW of the fixed - coastal radar -- this is a small-vessel unit) - Antenna type: Radome (enclosed dome, ~60 cm diameter) -- - more rugged and lower wind resistance than - an open array, typical for patrol boats - Horizontal beamwidth: 4 to 6 degrees (vs 0.5 deg for the big - coastal radar -- targets will appear as - noticeably fatter blips; good exhibit contrast) - Antenna height: 2 to 3 meters above waterline (radar arch - or short mast on a 25-35 foot patrol vessel) - - RADAR HORIZON at 2.5 m antenna height: - horizon = 2.23 x sqrt(2.5) = approx 3.5 nautical miles - (~4 statute miles) to a sea-level target. - Compare: fixed coastal radar at 15 m sees ~8.6 nautical miles. - - MAX RANGE DECISION: 2 miles maximum. - The patrol boat's job is close-in situational awareness, not - long-range surveillance (the fixed coastal radar handles that). - 2 miles puts the entire inner harbor on screen at once. - - RANGE STEPS: 0.5 / 1 / 2 miles. - Tighter steps than the fixed marine scopes (2/4/6) because the - officer needs a close-in zoom for marina and waterway work: - 0.5 mi -- tight quarters, marina basin, Whatcom Waterway - 1.0 mi -- inner harbor, near-shore patrol - 2.0 mi -- full harbor picture, ferry lane monitoring - - SMALL TARGET DETECTION NOTE (important for exhibit realism): - A paddleboard or kayak is a marginal radar target at any range. - Very small RCS, almost no freeboard. At 2-4 kW with 4-6 degree - beamwidth, a paddleboarder may show as a faint intermittent blip - or may wash into the noise floor entirely -- especially in chop. - A kayak carrying a small aluminum radar reflector shows much - better. This is realistic and worth simulating: the exhibit - shows visitors that radar does not see everything, and that - small non-metallic targets are genuinely hard to detect. - - FERRY LANE SCENARIO: - The Bellingham terminal serves the Alaska Marine Highway System - (state ferries up to 400 feet). A paddleboarder or kayaker - drifting into the departure lane is a real hazard the patrol - officer watches for. Simulated small targets (paddleboards, - kayaks) near the ferry lane would make a compelling exhibit - moment -- visitor tries to spot them on the radar before the - ferry moves. - - 5. Should the left panel description explain that this is a moving - platform, and show the current boat position (lat/lon or a - simple text description of where on the route the boat is)? - - 6. I do not care about the size or material of the police boat - itself since it is the platform the radar is mounted on, not - a target. diff --git a/additions-comments b/additions-comments deleted file mode 100644 index e69de29..0000000 diff --git a/additions.lidar b/additions.lidar deleted file mode 100644 index fba0765..0000000 --- a/additions.lidar +++ /dev/null @@ -1,36 +0,0 @@ -I just added the following directories (alrady mentioned in the existing CLAUDE.md file -./map -./map/lidar_processed -./map/charts_enc -./map/charts_enc/US5WA45M.000 -./map/charts_enc/n48_w123_1arc_v3.tif -./map/lidar_raw -./map/lidar_raw/wa2022_nooksack_dem_J1364940.zip -./map/lidar_raw/wa2016_west_dem_J1364939.zip - -We need code for the marine a scope and marine ppi scope and the -on-boat ppi radar to show reflectivity from the ./map/charts_enc/US5WA45M.000 -and ./map/charts_enc/n48_w123_1arc_v3.tif (include whatever addional shader -files that may be needed. Consider with the topographical map the effect of higher hils -closer to lower hills will shadow the lower hills from the radar where ever the radar is, -which will change if there is a radar on a boat. - -The ./map/lidar_raw/wa2016_west_dem_J1364939.zip contains information for the lidar -mapping of any man made structures, including features on the waterfront; breakwaters, -piers, and structures built over the water such as the boulevard park boardwalk - -We will need to include the information in the ./map/lidar_raw/wa2016_west_dem_J1364939.zip -file to contribute to the reflection on the shore and land features. - -The marine a-scope and the maring PPI scope and the on boat ppi scope needs to show these -features. - -The Air traffic control radar in the day would blank out the shore features, but would show -the effects of shadowing of aircraft by the taller hils. - -The land featuresl should be subject -to the effects of the radar equation. Consider the materials be soil, rock, and concrete. - -In order to provide visual balance, the grain for returns of the shoreline, the mountains and -hills and the man made structures should be included in the settings.h file and DESIGN.md file -