Homestake Meeting Minutes, 05/01/2014
Attending: Vuk, Gwynne, Tanner,
Homestake wiki: https://zzz.physics.umn.edu/groups/homestake/home
1) Homestake update (Vuk)
Vuk: proposal for GPS distribution system, from Liteway https://zzz.physics.umn.edu/_media/groups/homestake/array/gpsdistsyst_liteway_proposal20140429.pdf
We should be able to operate without powered equipment at most of the gates/landings, since we can use passive splitters. Trying to confirm this with the SDSTA. Power consumption at each station is 125mA at 12V, 1.5 W, with potential further improvements.
Tanner: this is a significant power consumption improvement, maybe factor of 2 compared to what we had in our test (55 Ahr battery lasted for 2 days with 11W consumption).
2) UMN test setup (Tanner)
Tanner: playing with different ways of accessing the data. Did tests of tapping the seismometer, and looking at the data to check if timing is ok. Download data from baler in multiplexed miniSEED format, which antelope can demultiplex, and create files for each channel (seismic channels, clock phase etc, temperature). Got code from Michael to read the miniSEED files, trying to look at them in matlab. The tapping times didn't quite match up, there is about 20 sec difference. Two reasons: one, the clock used was the PC clock to record the tap times. Two, not sure if digitizer is recording UTC or GPS times (probably UTC), there is about 16 sec difference between the two (due to leap seconds). Will redo the experiment with an actual GPS clock (not something based on the PC clock).
Also, not sure of the units of the output. Have to find the calibration factor, conversion from bits to volts.
3) Analysis of existing data
a) Frames/miniSEED files (Shivaraj, Tanner, Michael) b) Estimation algorithms (Shivaraj, Eric, Noah)