Keynote: Characterization of GPS Satellite Anomalies for SVN 63 (PRN 1) Using a Dish Antenna

Rakesh Kashyap Hassana Ramesh, Sabrina Ugazio, and Frank van Graas

Peer Reviewed

Abstract:	In safety of life applications, or in general, in applications implying commercial impacts, satellite navigations systems have become a key-factor. Therefore, a certain level of reliability is required for the PVT (Position, Velocity and Time) solution. The observable of interest for high accuracy applications is the carrier phase measurement, which enables cm-level accuracy. To assure cm-level accuracy, signal quality monitoring is carried out at mm level. High accuracy GPS applications require anomaly monitoring and detection processes to sustain safety, which translates into requirements for integrity, continuity and availability [1]. The focus of this paper is on GPS satellite signal anomalies, in particular on SVN 63 (PRN 1) a block IIF satellite, which showed 18 satellite anomalies during a 28 day observation in Sept 2016. A high-gain antenna is used to enable low noise and low multipath GPS measurements. Moreover, a Novatel OEM7TM is used as it can provide L1, L2 and L5 measurements at 100 Hz. This work aims to provide some initial observations and analysis with the final objective to enable a characterization of satellite phase anomalies, in particular in terms of frequency of occurrence and carrier-phase patterns (such as step or finite-ramp patterns). From March 19th to March 29th 2017, SVN 63 was under observation with a high-gain dish antenna for a total of 102.54 hours. Eleven malfunctions (six steps and five finite-ramps) were detected. All the step malfunctions show similar trend on L1 and L2 carrier frequencies. All the finite-ramps malfunctions show similar trends on L1, L2 and L5 frequencies. The measured phase distribution of the step-shaped anomalies ranges between 23.460 – 25.930 in magnitude, while the measured phase distribution of the finite-ramp malfunctions ranges between 13.380 – 48.10 in magnitude. A much shorter duration data collection was conducted with the Novatel OEM7TM aided with a Septentrio PolaRxTM’s oscillator from April 14th to April 15th returned with only one anomaly (finite-ramp) with in magnitude.
Published in:	Proceedings of the ION 2017 Pacific PNT Meeting May 1 - 4, 2017 Marriott Waikiki Beach Resort & Spa Honolulu, Hawaii
Pages:	167 - 182
Cite this article:	Ramesh, Rakesh Kashyap Hassana, Ugazio, Sabrina, van Graas, Frank, "Keynote: Characterization of GPS Satellite Anomalies for SVN 63 (PRN 1) Using a Dish Antenna," Proceedings of the ION 2017 Pacific PNT Meeting, Honolulu, Hawaii, May 2017, pp. 167-182. https://doi.org/10.33012/2017.15081
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In