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| Homestake Meeting, 01/09/2014 | Homestake Meeting, 01/09/2014 | ||
| - | Attending: | + | Attending: |
| + | 1) PASSCAL communications (Vuk, Gary, Tanner) | ||
| + | Gary spoke with Tim Parker at PASSCAL. Several outcomes: | ||
| + | a) We have all the wireless radios we want to use. They have more than the number we need for surface sites. | ||
| + | Have anthena on Yates, and line of sight to the surface stations. We need to discuss if they could play a role | ||
| + | in some underground sites. That is, if a door isn't it the way we could potentially deploy instruments totally | ||
| + | autonomously and do comms wireless down the drift. | ||
| + | Vuk: attempted wireless communication in the drifts in the early days, didn't work well. Also, there are usually | ||
| + | turns in the drifts, difficult to get a direct line of sight. | ||
| - | 1) PASSCAL communications (Vuk, Gary, Tanner) | + | b) Multiple solutions exist for sending time that are off the shelf. |
| - | a) availability of instruments | + | |
| - | | + | some hardware. There may also be vendors selling repeaters of the GPS signals, eg used for subway tunnels etc. We |
| + | would need to speak with the vendors to understand exactly what signals are being repeated, and make sure this is | ||
| + | what the Q330 would require... | ||
| + | |||
| + | c) Disposable batteries: air cells are an option to consider. | ||
| + | | ||
| + | | ||
| + | Vuk: batteries may really be the way to go. All of the locations we are considering are accessible via rail or other vehicles. | ||
| + | So it shouldn' | ||
| + | |||
| + | Gary: Also, maybe could use DC voltage supply over a ~2km cable. Should check with SURF whether there are cost savings | ||
| + | if we go with this option, as opposed to AC power. | ||
| + | Shivaraj: there are constraints due to fire-hazard on the insulation material etc, which drive the costs up. | ||
| 2) UMN test setup (Tanner) | 2) UMN test setup (Tanner) | ||
| + | Tanner: Received the first Q330 from PASSCAL, starting to set it up in the lab at Minnesota. Should have more to say next meeting. | ||
| + | Vuk: the idea is to gain experience with this system and learn how to use the GPS with Q330. Then we can start talking to | ||
| + | vendors and others to understand how to set up synchronization. | ||
| 3) Analysis of existing data | 3) Analysis of existing data | ||
| a) Frames/ | a) Frames/ | ||
| + | Shivaraj: produced frames for another 2 months of data, currently at Caltech. Continuing to produce frames for other data. | ||
| + | Timing synchronization is at 1 ms, so not too bad. But data usually does not include all stations. Also, observe DC level | ||
| + | shifting over time in discontinuous steps, on varying time-scales (sometimes even shorter than 10 sec). | ||
| + | Gary: are you dropping bits? Are the steps powers of two? Are there ripples in the series? | ||
| + | Shivaraj: appear to be sharp jumps. | ||
| + | Gary: so it is probably digital, otherwise there would be some ringing in the time series. Check if these are power of 2 jumps... | ||
| + | Shivaraj: see it in 4100A, could be present in other stations as well. Suspect we should be able to find another good patch of data. | ||
| + | |||
| b) Wiener filtering (Michael, Jan) | b) Wiener filtering (Michael, Jan) | ||
| - | c) Estimation algorithms (Shivaraj, Eric) | ||
| + | c) Estimation algorithms (Shivaraj, Eric) | ||
| + | Shivaraj: planning to add P and Rayleigh filters into 1 filter. | ||
| + | Vuk: Had a discussion with Eric and Shivaraj about this. Roughly, Shivaraj will aim to complete his study by combining the P and | ||
| + | R filters into one, test it on simulations, | ||
| + | a publication. Eric will take a longer-term approach, trying to incorporate all wave modes, address computational issues that will | ||
| + | probably arise, and study possible degeneracies between different modes. | ||