11:00 AM - 11:15 AM
[J04-6-03] Real-time multi-GNSS precise point positioning for earthquake and tsunami early warning over Asia-Pacific regions
Real-time GNSS precise point positioning (PPP) is capable of measuring centimeter-level positions epoch by epoch at a single station, and is thus treasured in earthquake and tsunami early warning where static displacements in the near field are critical to rapidly and reliably determining the magnitude of destructive events. However, most operational real-time PPP systems at present rely on only GPS data. The deficiency of such systems is that the high reliability and availability of precise displacements cannot be maintained continuously in real time, which is however a crucial requirement for disaster resistance and response. Multi-GNSS, including GLONASS, BeiDou, Galileo and QZSS other than only GPS, can be a solution to this problem because much more satellites per epoch (e.g. 30-40) will be available. In this case, positioning failure due to data loss or blunders can be minimized, and on the other hand, positioning initializations can be accelerated to a great extent since the satellite geometry for each epoch will be enhanced enormously. This in turn will improve greatly the success rate of ambiguity fixing which, critically, plays as an indicative and guarantee of successful achievement of centimeter-level ground displacements. We established a prototype real-time multi-GNSS PPP service based on Australian national network which can collect and stream high-rate data from all five navigation systems above. We estimated high-rate satellite clock corrections and enabled undifferenced ambiguity fixing for multi-GNSS, which therefore ensures high availability and reliability of precise displacement estimates in contrast to GPS-only systems. We will report the preliminary performance of this service and analyze its potential to earthquake and tsunami early warning.