197 lines
5.6 KiB
Markdown
197 lines
5.6 KiB
Markdown
# SatMaster — F4BPO Satellite Tracker
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Amateur satellite tracking application with Doppler correction for FlexRadio 8600 and rotor control via PstRotator.
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**Stack:** Go + Wails v2 + Svelte
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**Platform:** Windows (primary), Linux/macOS (compilable)
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---
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## Features
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- 🗺️ **World map** — real-time satellite positions on Leaflet dark map, footprint overlay
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- 📡 **Polar plot** — az/el pass track with AOS/LOS markers, current position animation
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- 🕐 **Pass prediction** — 24h upcoming passes, Max El, duration, quality rating
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- 📻 **Doppler correction** — automatic TX/RX frequency correction via FlexRadio 8600 TCP API
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- 🔄 **Rotor control** — Az/El commands to PstRotator via UDP XML protocol
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- 🛰️ **TLE management** — auto-fetch from tle.oscarwatch.org with local cache fallback
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---
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## Architecture
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```
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SatMaster/
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├── main.go # Wails entry point
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├── app.go # App struct, Wails bindings, position loop
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├── wails.json # Wails project config
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│
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├── backend/
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│ ├── tle/
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│ │ └── manager.go # TLE fetch (oscarwatch.org), cache, parse, lookup
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│ │
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│ ├── propagator/
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│ │ └── engine.go # SGP4 propagation, az/el, pass prediction
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│ │
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│ ├── doppler/
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│ │ └── calculator.go # Doppler shift computation (range rate → Hz correction)
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│ │
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│ ├── flexradio/
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│ │ └── client.go # FlexRadio SmartSDR TCP API (port 4992)
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│ │
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│ └── rotor/
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│ └── pstrotator.go # PstRotator UDP XML protocol (port 12000)
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│
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└── frontend/src/
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├── App.svelte # Root layout, Wails event subscriptions
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├── stores/satstore.js # Svelte stores for all app state
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├── lib/
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│ ├── wails.js # Wails Go call bridge + dev stubs
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│ └── utils.js # Formatting helpers (freq, az, el, etc.)
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└── components/
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├── StatusBar.svelte # Top bar: clock, sat data, Doppler, connections
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├── SatSelector.svelte # Left sidebar: search + quick-select + full list
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├── WorldMap.svelte # Leaflet map with sat markers + footprints
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├── PolarPlot.svelte # SVG polar az/el plot
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├── PassesPanel.svelte # Pass list + detail + embedded polar plot
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└── SettingsPanel.svelte # QTH, frequencies, FlexRadio, rotor, TLE
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```
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---
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## Prerequisites
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```bash
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# Go 1.21+
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# Node.js 18+
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# Wails v2
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go install github.com/wailsapp/wails/v2/cmd/wails@latest
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# Verify
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wails doctor
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```
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---
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## Setup & Build
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```bash
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# 1. Clone / copy project
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cd SatMaster
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# 2. Download Go dependencies
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go mod tidy
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# 3. Install frontend deps
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cd frontend && npm install && cd ..
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# 4. Development mode (hot reload)
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wails dev
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# 5. Production build (single .exe)
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wails build
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# → build/bin/SatMaster.exe
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```
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---
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## FlexRadio 8600 — Protocol Notes
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SatMaster uses the SmartSDR **TCP API** on port **4992**.
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Commands sent:
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```
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C1|slice set 0 freq=145.800000 # Set RX frequency (MHz)
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C2|transmit set freq=145.200000 # Set TX frequency (MHz)
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```
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- Connect: Settings → FlexRadio 8600 → enter IP → Connect
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- The active slice index is 0 (Slice A) by default
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- Doppler correction fires every second during active tracking
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- Dead-band: updates only sent when shift exceeds ~10 Hz
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---
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## PstRotator — Protocol Notes
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SatMaster sends **UDP XML** to PstRotator on port **12000** (default).
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```xml
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<PST><CMD>SET</CMD><AZ>180.0</AZ><EL>45.0</EL></PST>
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```
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- Configure in PstRotator: Setup → UDP Server → Port 12000
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- Dead-band: 0.5° Az and El to prevent rotor hunting
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- Elevation is clamped to [0°, 90°] — no negative elevation commands sent
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---
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## TLE Data
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- **Primary source:** `https://tle.oscarwatch.org/nasabare.txt`
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- **Fallback:** Celestrak SOCRATES
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- **Cache:** `%LOCALAPPDATA%\SatMaster\satmaster_tle_cache.txt` (Windows)
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- **Bundled fallback:** ISS, AO-7, AO-27, SO-50 (always available)
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- TLE age shown in status bar; highlighted orange if > 48h
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---
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## Pass Prediction
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- Step: 10s (30s when satellite below -15° elevation)
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- AOS/LOS bisection precision: 1 second
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- Horizon: passes below 5° Max El are filtered from the list
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- 24-hour prediction window
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---
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## Doppler Formula
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```
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f_corrected_down = f_nominal × (1 - v_range / c)
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f_corrected_up = f_nominal / (1 - v_range / c)
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where:
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v_range = range rate in km/s (+ = receding, - = approaching)
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c = 299792.458 km/s
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```
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---
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## Keyboard Shortcuts
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| Key | Action |
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|-----|--------|
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| `M` | Switch to Map tab |
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| `P` | Switch to Passes tab |
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| `S` | Switch to Settings tab |
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---
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## Adding More Satellites
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The app loads all satellites from the TLE feed (~2000+ amateur sats from OscarWatch).
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Use the search box in the satellite selector to find any satellite by name or NORAD catalog number.
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Common amateur satellites available:
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- ISS (ZARYA) — 145.800 MHz FM voice
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- AO-7 — 145.975 MHz / 29.502 MHz linear transponder
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- AO-27 — 145.850 MHz FM
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- SO-50 — 436.795 MHz FM
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- RS-44 — 435.640 MHz / 145.935 MHz linear
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- PO-101 (Diwata-2) — 437.500 MHz FM
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- XW-2A/B/C/D — CW/linear transponders
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- CAS-4A/B — linear transponders
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---
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## Future Enhancements
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- [ ] Ground track on world map (lat/lon per pass point)
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- [ ] Multiple satellite tracking (split-screen polar)
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- [ ] Audio squelch mute between passes
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- [ ] Log4OM integration for contact logging
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- [ ] Satellite database with nominal frequencies auto-loaded
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- [ ] AOS/LOS audio alert
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- [ ] Export pass schedule to CSV/PDF
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