Understanding GPS Accuracy
GPS accuracy depends on:
- Number of visible satellites
- Atmospheric conditions
- Physical obstructions
- Device hardware
- Software settings
Common Accuracy Problems
Jumping Location
Your position jumps around on the map.
Causes:
- Weak satellite signal
- Multi-path interference (signals bouncing)
- GPS recalculating
Solutions:
- Wait in an open area for GPS lock
- Ensure nothing blocks sky view
- Hold phone upright, not flat
Drifting Track
Your recorded path shows you in places you didn't go.
Causes:
- Temporary signal loss
- Interference from buildings/trees
- Atmospheric effects
Solutions:
- Enable track smoothing in settings
- Edit track after recording to remove drift
- Use best-effort GPS mode
No GPS Signal
The app can't determine your location.
Causes:
- GPS disabled in settings
- Location permissions denied
- Hardware issue
- Being indoors/underground
Solutions:
- Check location is enabled in device settings
- Verify ALTLAS has location permission
- Move outdoors to open area
- Restart your device
Optimizing GPS Settings
On iPhone
- Settings then Privacy then Location Services
- Find ALTLAS
- Select While Using the App
- Enable Precise Location
On Android
- Settings then Location
- App permissions then ALTLAS
- Select Allow only while using the app
- Enable Use precise location
- Set location mode to High accuracy
Environmental Factors
Best Conditions
- Open sky view
- Clear weather
- Away from tall buildings
- Stable position
Challenging Conditions
- Dense forest canopy
- Urban canyons (tall buildings)
- Deep valleys
- Indoor/underground
Weather Effects
- Heavy cloud cover: Minimal impact
- Rain/snow: Slight reduction
- Solar storms: Can affect accuracy
Hardware Tips
Phone Position
- Keep phone upright if possible
- Don't cover GPS antenna area
- Avoid metal cases that block signal
GPS Chip Quality
Different phones have different GPS chips:
- Newer phones generally better
- Some phones have dual-frequency GPS
- Check your device specs
ALTLAS Settings
GPS Mode
Choose accuracy vs battery:
- High Accuracy - Best quality, more battery
- Balanced - Good accuracy, reasonable battery
- Battery Saver - Reduced updates, longer battery
Track Smoothing
Reduce erratic points:
- Go to Settings then Recording
- Enable Track Smoothing
- Choose smoothing level
Point Recording Interval
Adjust recording frequency:
- 1 second - Most detail, more battery
- 5 seconds - Good balance
- 10+ seconds - Battery saver mode
Fixing Recorded Tracks
In-App Editing
- Open the activity
- Tap Edit
- Select problem points
- Tap Delete or Smooth
Automatic Correction
Enable post-processing:
- Settings then Recording
- Enable Auto-correct GPS
- App fixes obvious errors after recording
When to Seek Help
Contact support if:
- GPS never works in ALTLAS
- Works in other apps but not ALTLAS
- Accuracy is consistently very poor
- Device shows GPS hardware error
Device-Specific Issues
iPhone
- Reset network settings may help
- Update to latest iOS
- Try resetting location & privacy
Android
- Clear cache for location services
- Update Google Play Services
- Check for phone manufacturer GPS updates