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