Loss-of-lock statistics from the GPS receiver near Suvarnabhumi airport, Thailand

Loss-of-lock (LOL) statistics are important to the study of the ionosphere and the availability of the GPS/GNSS technology. The LOL data of the GPS, for instance, together with the spread-F and the rate of TEC change index (ROTI) are often used to the study of plasma bubble occurrence in the low and equatorial latitudes. In our work, we collected the data from the GPS receiver near Suvarnabhumi airport, Thailand, in 2010 and investigated the LOL statistics during this time. The number of proposed parameters including the probability of visible GPS satellites with LOL, and the number of usable GPS satellites are used to evaluate the LOL statistics. A comparison of the probability of LOL on both GPS frequency carriers indicates that the L₂ frequency is more susceptible to the LOL events than L₁ frequency. The results also show that the dense LOL occurrence is related to high fluctuation ROTI. The inversely correlation between elevation angles and number of visible GPS satellites with LOL is obtained as well.