This is with reference to the volcano monitoring paper of Matt Welsh and his team (mentioned below).
In this paper, two problems have been mentioned with regards to FTSP.
1) The problem with the clock driver (apparently seen only on Tmotes) that seems
to return bogus timestamps.
2) FTSP does not check validity of time sync messages.
The first seems to have been fixed in the change to TimerM.nc in /tos/platform/msp430
done in February 2006.
Does this guarantee that there will be no bogus timestamps anymore ?
Given the fact that this fix has been done, can we assume that the time filtering/time
rectification approach mentioned in the paper is not required anymore ?
Regards,
Harish
On 9/20/06, Omprakash Gnawali <[EMAIL PROTECTED] > wrote:
Matt Welsh and his group has an OSDI paper:
Fidelity and Yield in a Volcano Monitoring Sensor Network
http://www.eecs.harvard.edu/~mdw/papers/volcano-osdi06.pdf
in which they report similar error. You might want to read that paper
if you are trying to use FTSP on Tmotes because the paper talks about
different techniques they used to get FTSP to work well.
- om_p
> Hi All,
> Has anyone tried FTSP on Tmotes ?
> If yes, what was the accuracy obtained ? Is it of the order of
> micro-seconds ?
> I was trying it but I cannot see better than millisecond accuracy.
> Regards,
> Harish
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