Undifferenced and single differenced GNSS noise analysis through a constrained baseline vector

GNSS noise characteristics can be obtained by short and zero baseline analysis, for both pseudorange and carrier phase measurements. Differencing observations from a GNSS satellite tracked by two GNSS receivers (connected to the same or different antennas) will explicitly eliminate common errors. In this contribution, the known baseline vector between the antennas will be used to adjust (“constrain”) the observation vectors. The advantages of a noise analysis through a constrained baseline vector over an ordinary baseline processing will be discussed and demonstrated using undifferenced and single differenced residuals obtained from dedicated experiments. The influence of multipath, known to be time correlated for sampling rates of 1 Hz or higher, will be also investigated. For static baselines, multipath effects of each GNSS satellite are repeated with a period close to a sidereal day due to the baseline-satellite geometry. In this contribution, we will demonstrate how this effect can be utilized to compensate for multipath errors on a constrained baseline vector.