@booklet {137, title = {Robust Estimation Methods Applied to GPS in Harsh Environments}, year = {2017}, abstract = {

Satellite navigation is very widespread in civil society; many devices and services exploit this technology and several systems are in use or in development phase. GNSS receiver, embedded in devices used in daily life (smartphones, cars and so on), works in several conditions and operational scenarios. Ensuring good positioning accuracy is challenging, especially in environment where receiver measurements are affected by gross errors, such as urban canyons. In this paper, the benefit of robust estimators in case of multiple simultaneous blunders is investigated; several robust estimators were implemented and their performances are compared with classical techniques used in GNSS context (WLS, RAIM) using real data. Effectiveness of these methods raised from tests conducted in static and kinematic mode.\ 

}, keywords = {Blunders, GNSS, GPS, Outliers, RAIM, Robust Estimation}, author = {Salvatore Gaglione and Anna Innac and Sonia Carbone Pastore and Salvatore Troisi and Antonio Angrisano} } @conference {135, title = {Reliability testing for multiple GNSS measurement outlier detection}, booktitle = {2016 European Navigation Conference (ENC)}, year = {2016}, month = {May}, abstract = {

Due to a rapid development of several Global Navigation Satellite Systems (GNSS), multiple constellations are available to enhance navigation performance and safety. With the growing number of satellite constellations, the task of the GNSS navigation is to deal with the differences among systems but, on the other hand, more great levels of integrity and satellite visibility can be expected. GNSS navigation applications have difficulties in signal degraded scenarios where the GNSS solution can be degraded by errors such as multipath and signals being obscured. RAIM (Receiver Autonomous Integrity Monitoring) is a method necessary for assessing integrity performance levels mainly in safety-critical applications. Classical RAIM techniques are based on the assumption model of a single outlier in the measurements, but with a future of higher satellite availability and for navigation conducted in urban canyon scenarios, the single outlier assumption is unrealistic. Therefore, reliability monitoring techniques need to be modified to be suitable for use cases with high signal degradation levels. The FDE (Fault Detection and Exclusion) schemes analysed in this research for reliability monitoring are the {\textquotedblleft}Observation Subset Testing{\textquotedblright} and a modified approach based on a w-test (called in this paper Multiple Faults De-weighting-MFD). In order to improve their performance a novel Channel Quality Index (CQI) parameter was used to describe the measurement confidence and quality. To validate the proposed approaches, tests have been performed using simulated data with GPS, Galileo and BeiDou signals in a multipath environment.

}, keywords = {BeiDou, channel quality index, Delays, fault detection and exclusion schemes, FDE, Galileo, global navigation satellite systems, Global Positioning System, GNSS, GPS, Indexes, Monitoring, Multi-Constellation, multiple faults de-weighting-MFD, multiple outliers, observation subset testing, RAIM, receiver autonomous integrity monitoring, Receivers, Reliability, reliability testing, satellite navigation, Satellite navigation systems, Satellites, telecommunication network reliability, urban canyon}, doi = {10.1109/EURONAV.2016.7530540}, author = {A. Innac and M. Z. H. Bhuiyan and S. S{\"o}derholm and H. Kuusniemi and S. Gaglione} } @conference {129, title = {Benefit of GNSS multiconstellation in position and velocity domain}, booktitle = {Metrology for Aerospace (MetroAeroSpace), 2015 IEEE}, year = {2015}, month = {June}, keywords = {Accuracy, architecture complexity, augmentation systems, aviation application, carrier smoothing code, Carrier Smoothing Code component, classical single point positioning technique, communication infrastructure, Filtering algorithms, Galileo, global navigation satellite systems, Global Positioning System, GLONASS, GNSS multiconstellation, GPS, Multi-Constellation, navigation infrastructure, oceanic areas, position domain, position velocity time algorithm, PVT, restrictive flight phase, satellite navigation, Satellites, Smoothing methods, Standards, surveillance infrastructure, velocity domain, video surveillance}, doi = {10.1109/MetroAeroSpace.2015.7180618}, author = {Gaglione, S. and Angrisano, A. and Freda, P. and Innac, A. and Vultaggio, M. and Crocetto, N.} } @conference {131, title = {GPS/Barometer augmented navigation system: Integration and integrity monitoring}, booktitle = {Metrology for Aerospace (MetroAeroSpace), 2015 IEEE}, year = {2015}, month = {June}, keywords = {ABAS, Accuracy, air navigation system, aircraft based augmentation systems, aircraft navigation, airplane sensor integration, Atmospheric measurements, Barometer, barometer sensor, barometers, civil aviation community, Data Fusion, GBAS, global navigation satellite systems, Global Positioning System, GNSS-based navigation, GPS, GPS-barometer augmented navigation system, ground based augmentation systems, ICAO, integrity monitoring, International Civil Air Navigation Organization, Kalman filter, Mathematical model, position accuracy, Radio Technical Commission for Aeronautics, RAIM, Reliability, required navigation parameters, RNP, RTCA, SBAS, Sea measurements, sensors, space based augmentation systems, system integrity}, doi = {10.1109/MetroAeroSpace.2015.7180647}, author = {Gaglione, S. and Angrisano, A. and Castaldo, G. and Gioia, C. and Innac, A. and Perrotta, L. and Del Core, G. and Troisi, S.} } @article {125, title = {Time-differenced carrier phases technique for precise GNSS velocity estimation}, journal = {GPS Solutions}, volume = {19}, year = {2015}, pages = {341}, chapter = {335}, abstract = {

Classically, a stand-alone GNSS receiver estimates its velocity by forming the approximate derivative of consecutive user positions or more often by using the Doppler observable. The first method is very inaccurate, while the second one allows estimation of the order of some cm/s. The time-differenced carrier phase (TDCP) technique, which consists in differencing successive carrier phases, enables accuracies at the mm/s level. A study on the existing TDCP velocity estimation algorithms has revealed that the use of different broadcast ephemeris sets to calculate the satellite positions and clock offsets produces a discontinuity in the TDCP measurements that affects the velocity estimation. We propose a method to overcome this limitation based on the use of the same set of ephemeris to calculate the satellite positions and clock offsets at consecutive epochs. We describe in detail the TDCP algorithm used, and the complete implementation in MATLAB is included.

}, keywords = {Ephemeris selection, GPS, TDCP, Velocity estimation}, issn = {1080-5370}, doi = {10.1007/s10291-014-0425-1}, url = {http://dx.doi.org/10.1007/s10291-014-0425-1}, author = {Freda, Pierluigi and Angrisano, Antonio and Gaglione, Salvatore and Troisi, Salvatore} } @article {84, title = {Performance assessment of GPS/GLONASS single point positioning in an urban environment}, journal = {Acta Geodaetica et Geophysica}, year = {2013}, pages = {1-13}, abstract = {

In signal-degraded environments such as urban canyons and mountainous area, many GNSS signals are either blocked or strongly degraded by natural and artificial obstacles. In such scenarios standalone GPS is often unable to guarantee a continuous and accurate positioning due to lack (or the poor quality) of signals. The combination of different GNSSs could be a suitable approach to fill this gap, because the multi-constellation system guarantees an improved satellite availability compared to standalone GPS, thus providing enhanced accuracy, continuity and integrity of the positioning. The present GNSSs are GPS, GLONASS, Galileo and Beidou, but the latter two are still in the development phase. In this work GPS/GLONASS systems are combined for single point positioning and their performance are assessed for different configurations. Using GPS/GLONASS multi-constellation implies the addition of an additional unknown, i.e. the intersystem time scale offset, which requires a sacrifice of one measurement. Since the intersystem offset is quasi-constant over a short period, a pseudo-measurement can be introduced to compensate the sacrifice.

The benefit after adding a pseudo-measurement has been demonstrated in a vehicular test.

}, keywords = {GLONASS, GNSS, GPS, Kalman filter, Pseudorange, RAIM, Single point positioning}, issn = {2213-5812}, doi = {10.1007/s40328-012-0010-4}, url = {http://dx.doi.org/10.1007/s40328-012-0010-4}, author = {ANGRISANO, A and GAGLIONE, S and GIOIA, C} }