Assessment of a Global System for Detecting Tsunami’s Using Space Based GNSS Bi-static Radar Technology
- Paper number
IAC-05-B2.1.07
- Author
Mr. Scott Gleason, Surrey Space Centre, University of Surrey, United Kingdom
- Year
2005
- Abstract
The dangers presented by the world’s oceans are well known. The lives lost due to the recent tsunami’s that struck Asia captured the World’s attention and presented a call to action for the scientific community. It appears that recent advances in ocean remote sensing technology may be in a position to contribute towards a solution to this problem. This new technology involves utilising the signals transmitted by navigation satellites, such as those of the GPS system and in the future those of the Galileo constellation. These signals are constantly being scattered off the surrounding seas and land, and these signals contain valuable and varied information on the Earth’s oceans. These signals are now being detected regularly from low Earth orbit using the experiment on board the UK Disaster Monitoring Constellation satellite. The signals have been found to behave as expected under a range of sea conditions. Many in the scientific community are convinced that this is a viable method for ocean sensing at satellite altitudes. The scientific applications of this technology tend to concentrate on obtaining high accuracy measurements, such as a precise sea surface height, for use in improving modelling and in advancing our understanding of ocean science. These pursuits are unquestionably worthwhile, but it is often overlooked that by changing our requirements, it may be possible that the effects of tsunami waves on the detected waveforms are “visible”. We can assume that the shape of the detected signal detected over the 10’s of Kilometre square glistening zone on the ocean’s surface will noticeable alter due to an added small periodic tilting effect across the surface. We will determine the instrument accuracy needed to detect this effect and explore the possibility of its realisation on future missions. Additionally, the altimetry accuracy obtainable using ranging techniques on the reflected signals maybe adequate for observing typical tsunami wave amplitudes (of approximately a meter or more). This is encouraged by the fact that the tsunami that devastated Asia was seen afterwards by JASON, TOPEX/Poseidon and Envisat. It seems possible that even if the high accuracies of current altimetry instruments are not obtainable at this stage using GNSS reflections, the larger amplitude tsunami waves will be visible and a low-cost constellation of this type could enable the coverage needed for a useful warning system. The fact that this technology uses passive signals and does not require a transmitter opens up additional possibilities by greatly reducing the cost of such projects. The time to start thinking about this application has arrived. A low-cost constellation of this sort could be used to backup or augment the existing systems of tsunami detection and warning currently in place or being developed. A plan will be presented in this paper proposing how this technology could enable relatively low-cost systems that would provide dense spatial coverage with quick measurement repeat times that could be connected to existing warning networks and hopefully avoid future disasters. The possible effects of tsunami waves on the time and frequency responses of ocean reflected signals will be analysed using ocean surface modelling techniques. As an Example, a coverage network will be analysed that could be implemented to monitor the several seas surrounding Korea, Japan and China for the presence of propagating tsunami waves.
- Abstract document
- Manuscript document
IAC-05-B2.1.07.pdf (🔒 authorized access only).
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