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development:gnss_calibration [2020/12/15 03:46] Tiege McCarthy |
development:gnss_calibration [2021/01/25 00:42] (current) Tiege McCarthy |
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* This day was cancelled due to high winds - had a meeting with Lucia, Jamie and Guifre instead. Tracking postponed until next week. (Tiege) | * This day was cancelled due to high winds - had a meeting with Lucia, Jamie and Guifre instead. Tracking postponed until next week. (Tiege) | ||
- | **Dec 8, 2020:**: | + | **Dec 8, 2020:** |
* Another cancellation, this time due to post-LBA maintenance on the cryo system. (Tiege) | * Another cancellation, this time due to post-LBA maintenance on the cryo system. (Tiege) | ||
- | **Dec 11, 2020:**: | + | **Dec 11, 2020:** |
* **Remote track on GPS IIRM-8:** fixed a few issues with the observing setup. First issue was time stamps in the shell wrapper not working on newsmerd - the date command was for some reason reading them as GMT+7 timezone despite the default output of date being in UTC. This has since been fixed. (Tiege) | * **Remote track on GPS IIRM-8:** fixed a few issues with the observing setup. First issue was time stamps in the shell wrapper not working on newsmerd - the date command was for some reason reading them as GMT+7 timezone despite the default output of date being in UTC. This has since been fixed. (Tiege) | ||
* Also fixed a bug in the recording script that occasionally caused a type error when writing out the data with numpy.savetxt(). (Tiege) | * Also fixed a bug in the recording script that occasionally caused a type error when writing out the data with numpy.savetxt(). (Tiege) | ||
* Wrote a script for doing manual (not scheduled) recording using the spectrum analyser - will be useful for when we need to calibration scans on quasars. (Tiege) | * Wrote a script for doing manual (not scheduled) recording using the spectrum analyser - will be useful for when we need to calibration scans on quasars. (Tiege) | ||
- | **Dec 15, 2020:**: | + | **Dec 15, 2020:** |
* **Draft observing guide:** I have written a rough guide outlining the steps required in order to undertake the GNSS tracks and recording which currently exists [[https://docs.google.com/document/d/1ZQYY4cJqCG02h52L18jyCAuboBhCwgeG2JhKxVYTsHk/edit?usp=sharing|on my google drive]] (Tiege) | * **Draft observing guide:** I have written a rough guide outlining the steps required in order to undertake the GNSS tracks and recording which currently exists [[https://docs.google.com/document/d/1ZQYY4cJqCG02h52L18jyCAuboBhCwgeG2JhKxVYTsHk/edit?usp=sharing|on my google drive]] (Tiege) | ||
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+ | **Jan 21, 2021:** | ||
+ | * **GPS050 tracks:** Finally have a run not being cancelled by weather. Running a full track of GPS050 today (and hopefully tomorrow pending weather) - trying a 3 degree offset on offsource scans as 1 degree was too little in our last run with valid data. Also trying some new spectrum analyzer settings - keeping RBW at 3 MHz and VBW at 10 MHz, but changing span to 999 MHz and sweep points to 333, this should remove the need to resample the data when reducing the data - should know by tomorrow. Ideally we will get another couple of tracks on this source next week to check experiment to experiment repeatability of the results. | ||
+ | * **Flux calibration** Assuming wind remains pleasant, will get some data on a couple of bright quasar sources - 1934-638 is a little too weak for our setup. Would also be good to get multiple sources so we can check SEFD estimations. Ended up getting a scan of 3C353. (Tiege) | ||
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+ | **Jan 22, 2021:** | ||
+ | * **GPS050 tracks:** Have a full track from Yesterday and a few hours from today. Needed to extend offset to 4 degrees as 3 degrees still had evidence of both L1 and L2 signal in beam. | ||
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+ | **Jan 25, 2021:** | ||
+ | * **Script changes:** Have changed the recorder to throw out traces from the spectrum analyzer that do not have the expected length - this simplifies data reduction as these traces would need to be removed prior to analysis normally. | ||
+ | * ** Data reduction:** Track from Jan 21 has been reduced and didn't seem to have many issues (other than incomplete traces) - off source scans with the 3 degree offset still have signal in them and therefore power levels are underestimated. Jan 22 data seems to have a little bit of signal still in the band unfortunately - not sure if its worth going to 5 degrees. Something seems to have happened in the second half of the track on Jan 22 - looks like L1 and L2 signal disappear completely after a certain time. Perhaps there was a windstow I missed, I will check the logs on newsmerd. | ||
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**TO DO**: | **TO DO**: |