The Effects of Aircraft Overflights on GPS Measurements

Lukas Marti, Frank van Graas, and Joseph Kelly

Abstract:	Observation at the Local Area Augmentation System (LAAS) Ground Facility (LGF) revealed the presence of brief signal anomalies that lead to receiver errors and loss-of-tracking. At some locations, these anomalies can occur several times during the day, thus reducing the continuity of the received GPS signals. Aircraft overflights of the LGF antennas were identified as one possible cause of anomalies. A controlled experiment was designed to characterize the effects of aircraft overflight on the LGF GPS receive antennas. Ohio University’s DC-3 research aircraft was equipped with a truth reference positioning system and flown at varying heights over the LGF antennas. At the LGF, a radio frequency (RF) data collection system was triggered to collect 10 s of data centered around anomalous tracking conditions as reported by one of the LGF GPS receivers. The RF data allow for detailed characterization of the signal anomaly during the aircraft overflights. Block processing techniques were used to analyze the received signal in 1-ms intervals, providing 1000 measurements per second. The paper presents results from several overflights during which the LGF GPS receivers experienced loss-oftracking. Detailed analyses of the RF data characterize the effect on the receiver tracking behavior. It is shown that aircraft overflights can cause measurement outages for any GPS receiver. The outage duration can exceed one second in an airport environment.
Published in:	Proceedings of the 2002 National Technical Meeting of The Institute of Navigation January 28 - 30, 2002 The Catamaran Resort Hotel San Diego, CA
Pages:	516 - 522
Cite this article:	Updated citation: Published in NAVIGATION: Journal of the Institute of Navigation
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