🇹🇷 Türkçe | 🇬🇧 English

GPS Test Pro is a professional Android application for testing and analyzing GPS/GNSS satellite signals. Developed with modern Android technologies, it provides real-time satellite tracking, signal analysis, and location information.

Built from scratch using Kotlin and Jetpack Compose with a modern MVVM architecture.

• Real-time signal strength visualization with bar charts
• Support for multiple constellations: GPS (USA 🇺🇸), GLONASS (Russia 🇷🇺), GALILEO (EU 🇪🇺), BEIDOU (China 🇨🇳), QZSS (Japan 🇯🇵), IRNSS (India 🇮🇳), SBAS
• Color-coded signal quality indicators:
  • 🟢 Green: Excellent signal (≥30 dB)
  • 🟡 Yellow: Good signal (20-30 dB)
  • 🔴 Red: Weak signal (<20 dB)
  • ⚪ Gray: No signal
• Visual indication of satellites used in position fix (✓)
• Grouped by constellation with country flags

• Real-time satellite positions on compass view
• Azimuth and elevation angle visualization
• Color-coded satellites by signal strength
• Cardinal directions (N, S, E, W) overlay
• Interactive satellite selection with highlighting

• Sensor-based digital compass with smooth animations
• Real-time heading display in degrees
• Cardinal and intercardinal directions (N, NE, E, SE, S, SW, W, NW)
• Compass calibration status with color indicators:
  • 🟢 Good: High accuracy
  • 🟡 Medium: Acceptable accuracy
  • 🟠 Low: Needs calibration
  • 🔴 Poor: Calibration required
• Built-in calibration guide
• Location information display

• Real-time location tracking on OpenStreetMap
• No API key required (uses OSMDroid)
• Breadcrumb trail showing last 100 locations
• 5-meter threshold for trail recording
• Automatic map centering and zoom
• Works offline with cached tiles

• Comprehensive location information:
  • Latitude and Longitude (6 decimal precision)
  • Altitude (meters)
  • Speed (km/h)
  • Accuracy (±meters)
  • Bearing (degrees)
  • UTC timestamp
• Satellite statistics:
  • Total visible satellites
  • Satellites used in fix
  • Breakdown by constellation
• Organized in beautiful Material 3 cards

• Detailed information for each satellite:
  • Satellite ID (SVID)
  • Constellation type and country
  • Signal strength (C/N0 in dB)
  • Signal quality rating
  • Elevation and azimuth angles
  • Ephemeris and Almanac status
  • Usage in position fix
  • Connection duration tracking
• Interactive satellite selection
• Sortable by constellation and ID
• Full-screen detail dialog

• Isometric 3D visualization of satellite positions
• Height-based satellite rendering
• Color-coded by signal quality
• Elevation circles (0°, 30°, 60°, 90°)

• Signal strength distribution chart
• Sorted by signal power (strongest to weakest)
• Visual bar representation
• Individual satellite signal bars

• Constellation distribution statistics
• Usage, quality, and weak signal metrics
• Visual density bars
• Per-constellation breakdown

• Application information and version
• Feature list
• Developer information
• Technical specifications
• Privacy policy link

• Modern Material 3 Design with dark theme
• Responsive layouts adapting to different screen sizes:
  • Compact (<600dp): Phones
  • Medium (600-840dp): Large phones, small tablets
  • Expanded (>840dp): Tablets
• Smooth animations and transitions
• Animated dropdown menu navigation
• Professional splash screen with fade-in animation
• Turkish localization throughout the app

• Language: Kotlin 1.9.22
• UI Framework: Jetpack Compose (BOM 2024.02.00)
• Architecture: MVVM (ViewModel + StateFlow)
• Minimum SDK: 24 (Android 7.0 Nougat)
• Target SDK: 35 (Android 15)
• Compile SDK: 35

• Jetpack Compose: Modern declarative UI
• Material 3: Latest Material Design components
• Lifecycle & ViewModel: State management
• Kotlin Coroutines & Flow: Asynchronous operations
• OSMDroid 6.1.18: OpenStreetMap integration (no API key)
• Google Play Services Location 21.1.0: GPS/GNSS access
• Accompanist Permissions: Runtime permission handling

• GnssStatus.Callback: Real-time satellite data
• LocationManager: GPS location updates
• SensorManager: Compass and orientation sensors
• StateFlow: Reactive state management

<!-- GPS & Location -->
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />

<!-- Sensors (Compass) -->
<uses-permission android:name="android.permission.ACCESS_SENSOR_DATA" />

<!-- Internet & Network (Map tiles) -->
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

<!-- External Storage (OSM cache, Android <=12) -->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

• Android Studio Hedgehog (2023.1.1) or later
• JDK 17
• Android SDK 35
• Gradle 8.7

1. Clone the repository

   git clone https://github.com/cektor/GPSTestPro.git
   cd GPSTestPro

2. Open in Android Studio

   • File → Open → Select project folder
   • Wait for Gradle sync

3. Build the project

   ./gradlew build

4. Run on device/emulator

   • Connect Android device or start emulator
   • Click Run (▶️) or press Shift+F10

5. Grant permissions

   • Allow location access when prompted
   • Enable GPS/Location services

1. Launch the app - Splash screen appears for 2.5 seconds
2. Grant location permission - Required for GPS access
3. Navigate between screens - Use the hamburger menu (☰) in top-right
4. View satellite signals - Signal screen shows real-time data
5. Track location - Map screen displays your position with trail
6. Analyze satellites - Details screen provides in-depth information
7. Check compass - Compass screen shows heading and calibration
8. Best results - Use outdoors with clear sky view

gps_test/
├── app/
│   ├── src/
│   │   ├── main/
│   │   │   ├── java/com/alg/gpstestpro/
│   │   │   │   ├── MainActivity.kt
│   │   │   │   ├── model/
│   │   │   │   │   └── SatelliteInfo.kt
│   │   │   │   ├── viewmodel/
│   │   │   │   │   └── GpsViewModel.kt
│   │   │   │   ├── ui/
│   │   │   │   │   ├── GpsTestApp.kt
│   │   │   │   │   ├── screens/
│   │   │   │   │   │   ├── SplashScreen.kt
│   │   │   │   │   │   ├── SignalScreen.kt
│   │   │   │   │   │   ├── SkyScreen.kt
│   │   │   │   │   │   ├── CompassScreen.kt
│   │   │   │   │   │   ├── MapScreen.kt
│   │   │   │   │   │   ├── DataScreen.kt
│   │   │   │   │   │   ├── SatelliteDetailsScreen.kt
│   │   │   │   │   │   ├── Satellite3DScreen.kt
│   │   │   │   │   │   ├── SignalHeatmapScreen.kt
│   │   │   │   │   │   ├── SatelliteDensityScreen.kt
│   │   │   │   │   │   └── AboutScreen.kt
│   │   │   │   │   ├── theme/
│   │   │   │   │   │   └── Theme.kt
│   │   │   │   │   └── utils/
│   │   │   │   │       └── ResponsiveUtils.kt
│   │   │   ├── res/
│   │   │   │   ├── drawable/
│   │   │   │   │   └── gpslogo.png
│   │   │   │   └���─ values/
│   │   │   └── AndroidManifest.xml
│   │   └── build.gradle.kts
│   └── proguard-rules.pro
├── gradle/
├── README.md
├── README-TR.md
└── privacy_policy.md

GPS Test Pro respects your privacy:

• ❌ NO personal data collection
• ❌ NO cloud synchronization
• ❌ NO third-party analytics
• ❌ NO advertising
• ✅ All processing is local
• ✅ Location data stays on device
• ✅ Open source and transparent

See Privacy Policy for details. Location data stays on device

• ✅ Open source and transparent

See Privacy Policy for details.

• GPS Testing: Verify GPS functionality on new devices
• Signal Analysis: Analyze satellite signal quality in different locations
• Navigation Development: Test location accuracy for navigation apps
• Outdoor Activities: Check GPS signal before hiking/camping
• Research & Education: Learn about GNSS constellations
• Troubleshooting: Diagnose GPS issues on Android devices

Contributions are welcome! Please feel free to submit a Pull Request.

1. Fork the project
2. Create your feature branch (git checkout -b feature/AmazingFeature)
3. Commit your changes (git commit -m 'Add some AmazingFeature')
4. Push to the branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

This project is developed for educational purposes.

ALG Yazılım & Elektronik Inc.
Fatih ÖNDER

• Android Jetpack Compose team for the amazing UI framework
• Material Design team for design guidelines
• OpenStreetMap contributors for map data

For issues, questions, or suggestions:

• Open an Issue
• Contact: [info@algyazilim.com]

• ✅ Initial release
• ✅ 10 functional screens
• ✅ Multi-constellation support
• ✅ Real-time satellite tracking
• ✅ OpenStreetMap integration
• ✅ Compass with calibration
• ✅ Material 3 design
• ✅ Responsive layouts
• ✅ Turkish localization