Single-Receiver Single-Channel Real-Time Validation of GNSS Data

Real-time quality control of GNSS measurements can be performed using a single-receiver single-channel approach. The local DIA procedure can be utilised for this purpose using only observations of the epoch where data are collected. A description of the proposed method is given in this paper. A geometry-free observation equation model is proposed. Due to rank deficiency during initialisation of the model, a reparameterisation of the model unknowns was performed. In addition, the ionosphere error is assumed changing relatively smooth as a function of time and its variation from its mean is modelled as a first order autoregressive process. For a short time window, the instrumental code delay and the phase bias including the sum of the initial phase, the phase ambiguity as well as instrumental phase bias are treated as constants. The dynamic and stochastic modeling of the method is presented, and initialisation of the filter is discussed. The quality control procedure is given and the internal reliability quantified by the Minimal Detectable Bias is discussed.