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Kvalita multi-GNSS přesného určení polohy bodů pomocí stochastického modelování parametru hodin
Mikoś, Marcin ; Kazmierski, Kamil ; Sośnica, Krzysztof
The quality of the International GNSS Service (IGS) station coordinates depends, among other things, on the type of oscillator located at the station in undifferenced GNSS solutions. A distinction of the clock standards can be made between internal, rubidium, cesium, and hydrogen maser clocks. The stability of time standards can vary by several orders of magnitude depending on the type of clock. Highaccuracy clocks allow for the introduction of stochastic modeling in the absolute positioning algorithms which contributes to faster solution convergence and superior position accuracy. In the Precise Point Positioning (PPP) measurement technique based on multi-GNSS, the clock parameter may be determined in two ways. Either it is estimated separately for each system, or a single clock parameter is determined for all systems, taking into account the inter-system biases. In this paper, we analyze the impact of stochastic modeling imposed on clock parameters on positioning in a multi-GNSS PPP solution. We use selected IGS stations observing GPS, GLONASS, Galileo, and BeiDou satellites. All analyses for the clock parameter are conducted for different types of oscillators along with the performance characteristics for each system. An important advantage of modeling the clock parameter is to stabilize the station vertical coordinate component in multi-GNSS PPP solutions.
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