Prediction and mitigation of ionospheric scintillation and tracking jitter for GNSS positioning

Global navigation satellite systems (GNSS) are affected by scintillation particularly at low (near equatorial) and high latitudes which can result in positioning errors. Thus it is important to mitigate this effect which can be accomplished either by making the receiver PLL more robust to these errors or by using software algorithms to mitigate the effect. One method in the latter category is to weight all the satellites in the positioning calculation inversely according to the scintillation effect on each of the satellite paths. This method has been found to be successful [2,4] when scintillation indices and spectral parameters for the received signals for all the satellite paths are available at each epoch but this requires extra specialized (expensive) equipment, such as GISTMs, to measure the scintillation which would not be available to the general user. Then, in this paper, use of this scintillation mitigation method without recourse to real measurements of the scintillation indices and spectral parameter is investigated. Thus the prediction and calculation of scintillation indices and also the carrier to noise ratio without real-time measurements are discussed and, then, the determination from these of the tracking jitter in the receiver´s phased lock loop, used for finding the weighting of all the paths in the position determination, is outlined.