Understanding Multipath Effects
Signal Characteristics
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Direct Signal
Clean, strong signal path directly from satellite
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Multipath Signal
Delayed, weaker signals from reflections
Impact on Measurements
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Range Errors
Typically 1-4 meters in urban environments
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Time Delays
Can cause pseudorange errors up to 20ns
Advanced Mitigation Techniques
Antenna Design
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Choke Ring Antennas
Reduces ground multipath by up to 75%
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Ground Planes
Minimizes low-angle reflections
Signal Processing
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Correlator Technology
Narrows tracking loops for better discrimination
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Multipath Estimating
Advanced algorithms detect and remove reflections
Software Solutions
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Adaptive Filtering
Real-time multipath detection and removal
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SNR Monitoring
Tracks signal quality for better weighting
Implementation Best Practices
Site Selection
Location Considerations
- Avoid reflective surfaces
- Maintain clear sky view
- Consider seasonal changes
- Evaluate surrounding structures
Equipment Setup
Setup Guidelines
- Optimal antenna height
- Proper ground plane installation
- Cable routing considerations
- Regular calibration checks
Performance Metrics
Signal Quality
SNR Threshold
>35 dB-Hz
Elevation Mask
15°
PDOP Limit
<3.0
Accuracy Improvements
Urban Areas
60-80%
Open Terrain
80-95%
Mixed Environment
70-85%
Processing Time
Real-time Filter
<1ms
Post-processing
<5ms
Convergence
<30s