GNSS Reliability Testing in Signal-Degraded Scenario

• Published in: International journal of navigation and observation Vol. 2013; no. 2013; pp. 1 - 12
• Main Authors: Angrisano, Antonio, Gioia, Ciro, Gaglione, Salvatore, del Core, G.
• Format: Journal Article
• Language: English
• Published: Cairo, Egypt Hindawi Puplishing Corporation 2013; Hindawi Publishing Corporation
• Subjects: Algorithms; GLONASS; GNSS; Navigation; Performance indices; Receivers; Satellites; Statistical tests
• ISSN: 1687-5990; 1687-6008
• DOI: 10.1155/2013/870365

Multiconstellation satellite navigation is critical in signal-degraded environments where signals are strongly corrupted. In this case, the use of a single GNSS system does not guarantee an accurate and continuous positioning. A possible approach to solve this problem is the use of multiconstellation receivers that provide additional measurements and allows robust reliability testing; in this work, a GPS/GLONASS combination is considered. In urban scenario, a modification of the classical RAIM technique is necessary taking into account frequent multiple blunders. The FDE schemes analysed are the “Observation Subset Testing,” “Forward-Backward Method,” and “Danish Method”; they are obtained by combining different basic statistical tests. The considered FDE methods are modified to optimize their behaviour in urban scenario. Specifically a preliminary check is implemented to screen out bad geometries. Moreover, a large blunder could cause multiple test failures; hence, a separability index is implemented to avoid the incorrect exclusion of blunder-free measurements. Testing the RAIM algorithms of GPS/GLONASS combination to verify the benefits relative to GPS only case is a main target of this work too. The performance of these methods is compared in terms of RMS and maximum error for the horizontal and vertical components of position and velocity.