In the last years, the use of GNSS (Global Navigation Satellite Systems) data has been gradually increasing, for both scientific studies and technological applications. High-rate GNSS receivers, sampling the signal at 50 Hz, are commonly used to study the electron density irregularities within the ionosphere. The ionospheric irregularities may cause scintillations, which are rapid and random fluctuations of the phase and the amplitude of the received GNSS signals. Usually, GNSS signals observed at an elevation angle lower than an arbitrary threshold (usually 15°, 20° or 30°) are filtered out from the sample, to remove the possible error sources due to the local environment where the receiver is deployed. Indeed, the signal scattered by environment (buildings, trees, etc.) could mimic ionospheric scintillation, because of the multiple scattering encountered by the signal passing through such structures. Although widely adopted, the cut on the elevation angle has some downsides, as it may under or overestimate the actual impact of multipath due to local environment. Certainly, an incorrect selection of the field of view spanned by the GNSS antenna may lead to the misidentification of scintillation events at low elevation angles. With the aim to tackle the non-ionospheric effects induced by multipath at ground, in this paper we introduce a filtering technique, termed SOLIDIFY (Standalone OutLiers IDentIfication Filtering analYsis technique), aiming at subtracting the multipath sources of non-ionospheric origin to optimise the field of view of a GNSS site. SOLIDIFY is a statistical filtering technique based on the signal quality parameters measured by the scintillation receivers. The technique is here applied and optimized on the data acquired by a scintillation receiver located at the Istituto Nazionale di Geofisica e Vulcanologia, in Rome. The results of the exercise show that, in the considered case of a noisy site under a quiet ionosphere, the SOLIDIFY optimization maximizes the quality, instead of the quantity, of the data.
D’Angelo, G., Spogli, L., Cesaroni, C., Sgrigna, V., Alfonsi, L., Aquino, M.H.O. (2015). GNSS Data Filtering Optimization for Ionospheric Observation. ADVANCES IN SPACE RESEARCH.
GNSS Data Filtering Optimization for Ionospheric Observation
SGRIGNA, Vittorio;
2015-01-01
Abstract
In the last years, the use of GNSS (Global Navigation Satellite Systems) data has been gradually increasing, for both scientific studies and technological applications. High-rate GNSS receivers, sampling the signal at 50 Hz, are commonly used to study the electron density irregularities within the ionosphere. The ionospheric irregularities may cause scintillations, which are rapid and random fluctuations of the phase and the amplitude of the received GNSS signals. Usually, GNSS signals observed at an elevation angle lower than an arbitrary threshold (usually 15°, 20° or 30°) are filtered out from the sample, to remove the possible error sources due to the local environment where the receiver is deployed. Indeed, the signal scattered by environment (buildings, trees, etc.) could mimic ionospheric scintillation, because of the multiple scattering encountered by the signal passing through such structures. Although widely adopted, the cut on the elevation angle has some downsides, as it may under or overestimate the actual impact of multipath due to local environment. Certainly, an incorrect selection of the field of view spanned by the GNSS antenna may lead to the misidentification of scintillation events at low elevation angles. With the aim to tackle the non-ionospheric effects induced by multipath at ground, in this paper we introduce a filtering technique, termed SOLIDIFY (Standalone OutLiers IDentIfication Filtering analYsis technique), aiming at subtracting the multipath sources of non-ionospheric origin to optimise the field of view of a GNSS site. SOLIDIFY is a statistical filtering technique based on the signal quality parameters measured by the scintillation receivers. The technique is here applied and optimized on the data acquired by a scintillation receiver located at the Istituto Nazionale di Geofisica e Vulcanologia, in Rome. The results of the exercise show that, in the considered case of a noisy site under a quiet ionosphere, the SOLIDIFY optimization maximizes the quality, instead of the quantity, of the data.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
