Mat-1.3656 Seminar on
numerical analysis and computational science
Monday, April 22, 2013, room
U322 at 14.15, Eirola & Stenberg
Sampsa Pursiainen, A! Department of Mathematics and Systems Analysis
Iterative alternating sequential method for radio tomography of asteroids
We present a feasibility study of the radio tomography of asteroids. We
consider the simplest and most robust type of a radio experiment and
physical model, related to the CONSERT (Comet Nucleus Sounding
Experiment by Radiowave Transmission) setup, where an orbiter measures
the propagation time and amplitude of a radio frequency signal between
the orbiter and a transponder placed on an asteroid's surface. Contrary
to CONSERT, we consider the simultaneous use of multiple transponders.
We study two main questions:
(I) what is the basic infomation
content (reconstruction potential) of the data and the minimum number
of transponders for recovering most of it; and
(II) how to formulate Bayesian methods for an efficient 3D reconstruction.
The results obtained suggest that
(i) the information content of the travel time data is robust and allows a unique reconstruction with suitable methods;
(ii) finding a reasonable reconstruction requires the use of more than three transponders;
(iii) reconstructions with the hierarchical prior model can be superior
to those corresponding to Tikhonov regularized solution of the inverse
problem; and,
(iv) producing an appropriate reconstruction necessitates finding a
balance regarding the maximal number of reflections taken into account
in the forward simulation, in order not to end up with a too sparse or
noisy set of data.