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Session B3: GNSS Augmentation Systems

Evaluation of Quasi – Zenith Satellite System L5S Signal
Chiu-Mei Wu and Shau-Shiun Jan, National Cheng Kung University, Taiwan; Takeyasu Sakai, Electronic Navigation Research Institute, Japan
Location: Grand Ballroom F
Date/Time: Wednesday, Jan. 31, 3:05 p.m.

The modernized global navigation satellite system (GNSS), with its improved signal structure and frequency diversity, is now developed and has been recognized throughout the world in the last decade. In addition, the satellite based augmentation system (SBAS) is one of the GNSS augmentation systems that improves accuracy and integrity in the field of aviation. Conventional SBAS uses a single constellation GNSS (GPS) single frequency (L1 band) signal to augment satellite positioning systems. To improve the position accuracy as well as to enhance integrity, the next-generation SBAS, called DFMC (dual-frequency multiconstellation) SBAS, augments positioning systems using both L1 and L5 band signals. Furthermore, there are many GNSS augmentation systems under development, such as the quasi-zenith satellite system (QZSS). The first QZSS satellite, called “Michibiki” was launched in 2010 and has been continuously broadcasting ranging signals and augmentation signals. Moreover, the new QZSS satellites launched in the summer of 2017 can transmit the L5S signal, which is identical to the L5 SBAS signal. Thus, the objective of this research is to develop a piece of equipment to assess the real augmentation performance of the QZSS L5S experimental signal in the Asia Pacific region.
We develop a piece of prototype equipment using software defined radio (SDR) technology for QZSS L5S signal reception to assess all the necessary signal processing techniques. The proposed SDR consists of a GNSS antenna, a Universal Software Radio Peripheral (USRP) platform, and a personal computer. The SDR implements all receiver chains, including the digital signal processing, performing signal acquisition and tracking of the available satellite signals, and decoding the navigation message and computing the observables needed by the positioning algorithm. To evaluate the performance of the QZSS L5S SDR, the acquired QZSS satellite is marked, and the value of acquired Correlation Peak to next Peak Ratio (CPPR) is calculated in the signal acquisition process, Finally, we apply several signal quality analysis (SQA) methods to analyze the L5S signal continuity and signal strength for various times. Moreover, the actual GPS and QZSS satellite data, signals, and measurements are analyzed for comparison.



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