Campuses:
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| groups:homestake:meetings:20140109 [2014/01/09 10:53] – mandic | groups:homestake:meetings:20140109 [2014/01/09 10:54] (current) – mandic | ||
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| in some underground sites. That is, if a door isn't it the way we could potentially deploy instruments totally | 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. | 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. | + | turns in the drifts, difficult to get a direct line of sight. |
| b) Multiple solutions exist for sending time that are off the shelf. | b) Multiple solutions exist for sending time that are off the shelf. | ||
| - | Vuk: this is the highest priority now. There are solutions developed by other users, but may require us to develop | + | |
| - | some hardware. There may also be vendors selling repeaters of the GPS signals, eg used for subway tunnels etc. We | + | 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 | + | 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... | + | what the Q330 would require... |
| c) Disposable batteries: air cells are an option to consider. | c) Disposable batteries: air cells are an option to consider. | ||
| for the station alone and double that if we have to feed a radio or a fiber optic device (one or the other or both | for the station alone and double that if we have to feed a radio or a fiber optic device (one or the other or both | ||
| are required of course underground). Lighter than standard acid batteries, about 1/4 weight, and disposable. | are required of course underground). Lighter than standard acid batteries, about 1/4 weight, and disposable. | ||
| - | 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' | + | 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. | + | 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. | + | 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) | ||
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| 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 | + | 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). | + | 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? | + | Gary: are you dropping bits? Are the steps powers of two? Are there ripples in the series? |
| - | Shivaraj: appear to be sharp jumps. | + | 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... | + | 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. | + | 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 | + | 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, | + | 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 | + | 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. | + | probably arise, and study possible degeneracies between different modes. |