GPS Read&Spoof

Scan GPS coordinates with your camera and instantly mock your device's location to match.

Point the camera at any screen or display showing coordinates — a trail camera, a weather station, a GPS device — and the app reads them via OCR and sets your phone's mock location to those coordinates. No manual typing required.

How It Works

1. Scan — The camera continuously analyzes frames using ML Kit text recognition. A centered scan-box overlay shows the target area, and only that crop is sent to OCR for speed and accuracy.
2. Parse — A forgiving coordinate parser extracts lat/lon pairs from messy OCR text. It handles common OCR confusions (O→0, l→1, Z→2, S→5, B→8, g→9), strips spurious spaces, and supports all three coordinate formats:
   • Decimal degrees — 50.123456 N, 14.456789 E
   • Degrees & decimal minutes — 50°10.050' N, 14°30.050' E
   • Degrees, minutes, seconds — 50°10'30.5" N, 14°30'05.0" E
   • Auto — detects the format automatically
3. Mock — Parsed coordinates are pushed to Android's LocationManager test providers (GPS_PROVIDER and NETWORK_PROVIDER), overriding your real GPS location for all apps on the device.

Supported coordinate layouts

The parser handles all combinations of direction-letter position (prefix/suffix) and lat/lon order:

Layout	Example
Suffix, lat-first	N 50.123 E 14.456
Suffix, lon-first	E 14.456 N 50.123
Prefix, lat-first	50.123 N 14.456 E
Prefix, lon-first	14.456 E 50.123 N

Features

• Continuous auto-scan — automatically detects coordinates as soon as they appear in the scan box. Adaptive debouncing: scans every 250 ms until coordinates are found, then slows to 1500 ms to save battery.
• Manual scan mode — toggle off continuous scanning and press Scan Now for a single burst scan (100 ms intervals until a result is found).
• Scan & Mock shortcut — a launcher long-press shortcut that opens the app and immediately triggers a burst scan.
• Coordinate validation — if newly scanned coordinates differ from the current ones by more than 0.5°, the app shows a confirmation prompt instead of silently applying them.
• Manual editing — lat/lon fields are editable. Type or paste coordinates in any supported format with or without direction letters.
• Live mock refresh — mock location is refreshed every second to ensure it persists for apps that poll GPS independently.
• OCR preview — the raw OCR text is shown at the top of the camera preview so you can verify what was read.

Requirements

• Android 8 (API 26) or higher
• Camera access
• Location access
• The app must be set as the Mock location app in Developer Options

Setup

1. Build and install the app on your device.
2. Open Settings → System → Developer options → Select mock location app and choose GPS Read&Spoof.
3. Launch the app and grant camera and location permissions.
4. Point the camera at a screen displaying GPS coordinates. The app will detect and mock them automatically.

Note: If mocking fails, the app shows a snackbar with a Settings action that takes you straight to Developer Options.

Tech Stack

• Kotlin + Jetpack Compose (Material 3)
• CameraX — camera preview and image analysis with backpressure strategy and Camera2 interop for disabled post-processing (edge enhancement, noise reduction, etc.) to preserve raw pixel data for OCR.
• ML Kit Text Recognition — on-device Latin text recognition (no internet required).
• LocationManager test providers — mocks GPS_PROVIDER and NETWORK_PROVIDER. The fused provider is intentionally left untouched so that apps using FusedLocationProviderClient (e.g. via microG) still receive the aggregated mock location.

Project Structure

app/src/main/java/cz/litoj/grs/
├── MainActivity.kt              — Entry point, permissions, intent handling
├── CameraReaderService.kt       — CameraX preview + image analysis, scan modes
├── TextRecognizer.kt            — ML Kit OCR wrapper
├── GpsCoordinateParser.kt       — OCR normalization, coordinate regex parsing & validation
├── LocationMocker.kt            — Test provider registration & mock location updates
├── GpsSpoofViewModel.kt         — UI state, coordinate state, one-time events
└── ui/
    ├── GrsScreen.kt             — Main screen layout & snackbar event handling
    ├── CameraPreviewSection.kt  — Camera preview, scan-box overlay, scan controls
    ├── CoordinateInputSection.kt— Lat/lon text fields, format selector, mocking lifecycle
    └── theme/                   — Material 3 theme, colors, typography

Building

./gradlew assembleDebug

For release builds, place a keystore.properties file in the project root with your signing credentials. If the file is absent, the release build type falls back to the debug signing config.

License

GPLv3