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Optimal Divergence-Free Hatch Filter for GNSS Single-Frequency Measurement.
Byungwoon Park1, Cheolsoon Lim2, Youngsun Yun3
1School of Aerospace Engineering, Sejong University, Seoul 05006, Korea. byungwoon@sejong.ac.kr.
Sensors (Basel, Switzerland)
|March 2, 2017
Summary
This study introduces an improved single-frequency Hatch filter using satellite-based augmentation system messages. The new filter enhances accuracy and reduces errors, making low-cost receivers perform like dual-frequency ones.
Area of Science:
- * GNSS (Global Navigation Satellite System) positioning
- * Signal processing and filtering techniques
Background:
- * The Hatch filter is a carrier phase-based code-smoothing technique.
- * It effectively reduces pseudo-range noise but can introduce ionospheric errors for low-elevation satellites.
- * Single-frequency (SF) receivers are prevalent but often limited in accuracy compared to dual-frequency (DF) systems.
Purpose of the Study:
- * To propose an optimal single-frequency (SF) divergence-free Hatch filter.
- * To mitigate ionospheric divergence errors using satellite-based augmentation system (SBAS) messages.
- * To enhance the performance of low-cost SF GNSS receivers.
Main Methods:
- * Development of an optimal SF divergence-free Hatch filter.
- * Integration of SBAS messages to correct ionospheric divergence.
- * Application of an optimal smoothing constant for the filter's window width.
Main Results:
- * The proposed filter demonstrates performance comparable to DF divergence-free Hatch filters.
- * Horizontal error was reduced from 57 cm to 37 cm.
- * Vertical accuracy improved by 25% compared to the conventional Hatch filter.
Conclusions:
- * The optimized SF Hatch filter effectively reduces ionospheric errors using SBAS data.
- * This advancement significantly improves positioning accuracy for SF GNSS receivers.
- * The proposed filter offers a cost-effective solution to achieve DF-level DGPS performance with SF receivers.
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