Detailed assessment of GNSS observation noise based using zero baseline data

In this research, the GNSS observation noise is assessed in details based on zero baseline data. The 24-h observations are collected from two CORS stations of Curtin University (32.0°S, 115.9°E) on February 8, 2017. The code and carrier phase observation noise is assessed in details for every system of GPS, GLONASS, BeiDou, Galileo, SBAS and QZSS and for every measurement type and every satellite. In addition, the observation noise by two different kinds of receiver is also assessed and compared. From the numerical results, we find that: (1) Among the six GNSS systems, the code noise of Galileo is the smallest, the noise of all observed Galileo code types are no more than 0.1 m and the noise of C8X is only around 1 cm; the GLONASS code noise is the biggest, the noise of code types C1C and C2C are around 0.25 m; (2) The noise can vary greatly for different code measurement types and there is at least one code measurement type in each system with noise smaller than 0.1 m; (3) For carrier phase, Galileo noise is slightly smaller than the other systems, the noise of all carrier phase types are smaller than 1 mm; GLONASS noise is the biggest, the noise of L2C and L2P are all bigger than 1 mm, some can reach about 1.7 mm; (4) Generally, there is no obvious noise difference for different carrier phase measurement types of each system, except for GLONASS, of which the noise of frequency band L2 is obviously bigger than that of L1; (5) For BeiDou, MEO and IGSO have similar carrier phase noise level, but the noise of GEO is clearly related to elevation angle, with the decrease of elevation angle, the noise will increase; (6) The carrier phase noise of different kinds of receiver may vary greatly, in this research, the numerical results show that the noise of JAVAD receiver are generally much smaller than TRIMBLE.