Yesterday, we carried out the survey for measuring the position of the NCal benches @NE: we measured the point on top of the calibrator, 1 for each bench.

The 2 points are named: NE_NCal_EB_05-T; NE_NCal_WB_05-T; with the label "EB" and "WB" meaning "East Bench" and "West Bench" respectively and "T" meaning "top" of the calibrator. We did not use the adapter of 20 mm height in this case, it was not necessary.

The result in VRS coordinates is reported in Tab.1, with the corresponding schemes of the survey shown in Fig.4.

Fig.1 to 3 show some pictures of the survey carried out and of the target points.

Last Tuesday May 20, we carried out the last survey for measuring the position of the NCal benches @WE: we measured the points on top of the 4 calibrators, 2 for each bench.

The 4 points are named: WE_NCal_SB_05-T; WE_NCal_SB_06-T; WE_NCal_NB_05-T; WE_NCal_NB_06-T; with the label "SB" and "NB" meaning "South Bench" and "North Bench" respectively, and "T" meaning "top" of the calibrator. For the points SB_05-T and NB_05-T we used an adapter of 20 mm height, further the standard nest of the reflector.

The result in VRS coordinates is reported in Tab.1, with the corresponding schemes of the survey shown in Fig.6.

Fig.1 to 6 show some pictures of the survey carried out and of the target points.

Yesterday during Tuesday maintenance, we carried out the survey for measuring the position of the NCal benches reference points @WE: 4 points plus 1 point on top of the calibrator for each bench.

The points are named WE_NCal_NB_01-NE; WE_NCal_NB_02-SE; WE_NCal_NB_03-SW; WE_NCal_NB_04-NW; WE_NCal_NB_05-T; WE_NCal_SB_01-NE; WE_NCal_SB_02-SE; WE_NCal_SB_03-SW; WE_NCal_SB_04-NW; WE_NCal_SB_05-T; with the label "NB" and "SB" meaning "north bench" and "south bench" respectively and "T" meaning "top" of the calibrator (in this case we used an adapter of 20 mm height, further the standard nest of the reflector - Fig.6).

The result in VRS coordinates is reported in Tab.1, 2 and 3, with the corresponding schemes of the survey in Fig.1, 2 and 3.

Fig.4 to 7 show some pictures of the target points.

Yesterday we carried out the survey for measuring the position of the 4 NCal reference points @WE and labeled: WE-NCal-01-NE; WE-NCal-02-NW; WE-NCal-03-SW; WE-NCal-04-SE.

The measured points are shown in the Photos1 to 3 attached, while Fig1 to 6 report the position of the Laser Tracker AT403 stations and the different points measured (two from each station).

Tab.1 reports the final result for the NCal reference points in VRS coordinates measured by each station and the average of 3 stations for each couple of points (north and south side of the tower).

Z coordinate is less accurate than X and Y, due to the subsidence of the building registered over-time that affects also the VRS reference points placed on the floor. Finally, the coordinates refer to the center of the SMR reflector, thus 25+10 mm up from the upper surface of the aluminium disk (see Fig3, 4 and 5).

On November 15, we completed the 19th height monitoring campaign of the North Tunnel - North End Building reference points.

Tab.1 summarizes the result of the survey and Fig.1 shows the longitudinal profile, that reports graphically the trend of the subsidence over time.

On October 30, we completed the 19th height monitoring campaign of the West Tunnel - West End Building reference points.

Tab.1 summarizes the result of the survey and Fig.1 shows the longitudinal profile, that reports graphically the trend of the subsidence over time.

Yesterday we carried out the survey for cheking the position of some of the NCal reference plate points @NE, those measurable and labelled as NCal_XX_02 in the starting survey (see also eLog53883) .

Tab.1 reports the final result in VRS coordinates obtained for the points measured and the different stations performed.

Fig.1 and 2 show some photos of the survey.

Yesterday, we carried out the survey to determine the VRS coordinates of the center of the top flange of the vacuum tank housing the NE Tiltmeter.

The flange center, labeled TILTNE_center, was calculated by measuring 4 diametrical points at 90°. Tab.1 reports the VRS coordinates obtained, Fig.1 to 4 some photos of the measured points and Fig.5 the scheme of the survey.

To determine the Z coordinate of the tiltmeter, it should be considered that Tab1. reports the coordinates referred to the center of the sphere (SMR target), so the Z has an offset of +25 mm from the top plane of the flange.

Last May 4, we carried out the topographic survey of the height difference (N201-N200; W201-W200) between the tunnel and the tower basement within both End Buildings. This height difference is subjected to differential subsidence over the years and has to be periodically monitored.

Tab.1 reports the results for the NE building (N201-N200) and Tab.2 for the WE building (W201-W200).

Fig.1 and Fig.2 show for both cases the relevant graph of the trend over time and the curve fitting.

Last Friday May 5, we carried out the survey to determine the VRS coordinates of the reference point "1500W_ROBOT_00", marked on the floor and needed for the robot calibration (Fig.5).

Fig.1 to 5 show some pictures of the survey and Fig.6 the scheme of the points measured.

The result in VRS coordinates is reported in Tab.1.

Yesterday we have completed the check of the position of the vacuum tube supports along the North Tunnel, for the part placed between @progr.1200m and @progr.1600m.

Tab.1 reports the results obtained as both local and VRS coordinates.

Fig.1 shows a detail of one of the points and Fig.2 the scheme of one of the station (St01).

In order to check the position of the vacuum tube axis in correspondence of the supports, consequently the several re-alignment operations carried out during past years, last Wed 11 Jan we carried out the survey of the position of some vacuum tube supports along the North Tunnel, placed between about @progr.1475m and @progr.1550m (partly inside North Tunnel and inside 1500N Building).

For convenience and speed of execution, the points taken as reference were placed on the upper metallic frame of the supports, whose position is at a constant deltaZ distance from the vacuum tube axis. Fig.1 reports a detail of one of the points and Fig.2 the scheme of the survey carried out.

Tab.1 reports the results obtained as both local and VRS coordinates.

After the installation @1500W Building of the floor supports and their tensioning (Fig.1), carried out for the future placement of the scientific equipments in the SQZ-R&D Lab, we made a check survey of the reference points located inside the SQZ-R&D Lab, in order to exclude any unwanted displacement.

The check has been carried out measuring, before and after the stiffening of the floor, the same reference points located inside and outside the Lab (Fig.2, 3 and 4) and surveyed by the same single station of AT403 laser tracker.

The first survey considered was that of framing the reference points in the VRS network, reported in eLog58222, while the second survey has been carried out last Wed, Jan 11.

Then, the difference of the Z coordinate between each reference point has been calculated, and the result is shown in Tab.1.

As reported, between the initial survey (Staz07) and after the installation of the structural reinforcements (Staz08), the differences of the deltaZs for each point located inside the Lab (1500W-06, 1500W-07 and 1500W-08) result less than 0.4 mm, thus within the accuracy of this kind of survey. Moreover, the differences are of the same order also for the all other points outside of the intervention area, therefore within the expected accuracy.

As conclusion, it can be stated that no raising of the height of the floor has been measured due to the floor stiffening.

Last Dec 6, we carried out the survey of the position of additional reference points located in the 1500W building and inside the SQZ-R&D Lab, required for future checks after the installation of the new apparatus inside the Lab.

Tab.1 reports the VRS coordinates obtained for the reference points measured, 1500W-01 to 1500W-05 in the building and 1500W-06 to 1500W-08 inside the Lab.

Fig.1 to 4 show some pictures of the survey.

The first ETRF position of the station VIRG00ITA (Fig.1) is now available on EUREF webpage https://www.epncb.oma.be/_networkdata/siteinfo4onestation.php?station=VIRG00ITA (see also previous eLog53935 and eLog55014).

The ETRF2000 coordinates calculated by EPN are the following (Tab.1), valid in the GPS calendar period 163/2022 - 211/2022, while the velocities are not availble yet.

The periodic monitoring campaing of the topographic heights of buildings and tunnels has been completed last week with the 14th survey of the link between the Central Building and the Mode Cleaner (see also related entries eLog 55893 and eLog 56068 for West and North Tunnel respectively).

Tab.1 reports the result of the survey and Fig.1 shows the CB-MC tunnel profile, containing graphically the trend of the subsidence over-time.

Last week we completed the 18th height monitoring campaign of the North Tunnel.

Tab.1 summarizes the result of the survey and Fig.1 shows the tunnel profile, that reports graphically the trend of the subsidence over time.

Last week we completed the 18th height monitoring campaign of the West Tunnel.

Tab.1 summarizes the result of the survey and Fig.1 shows the tunnel profile, that reports graphically the trend of the subsidence over time.

Since last February 8, the GNSS Permanent Station VIRG00ITA (see also eLog 53935) is present in the list of "Proposed Stations" of the EUREF Permanent GNSS Network https://www.epncb.oma.be/_networkdata/proposed.php, an important step for the final insertion of VIRG00ITA in the European Network of GNSS permanent stations https://www.epncb.oma.be/.

The RinexV3 data are now available also through the dedicated station link https://www.epncb.oma.be/_networkdata/datacalendar.php?station=VIRG00ITA&year=2022&month=2&rv=3&c=epn

VIRG00ITA GNSS Permanent Station installed on site [Fig.1; 2; see also eLog 49054] is part of the Italian GNSS Fiducial Network of the Italian Space Agency (ASI). The station is monitored remotely from ASI/CGS (Centro di Geodesia Spaziale) in Matera, where its data are collected and routine QC activity is performed.

Starting from 17/11/2021 (doy 321), the data acquired by VIRG00ITA are available in the database GeoDAF of ASI.

In detail, the hourly data are collected in:    ftp://geodaf.mt.asi.it/GEOD/GPSD/NRTDATA/yyyy/doy
and the daily data in:                                 ftp://geodaf.mt.asi.it/GEOD/GPSD/RINEX_V3/yyyy/doy

This is the first important step for the next insertion of the station in the EUREF Permanent GNSS Network:
https://www.epncb.oma.be/

first as "Proposed Station" and then, finally, be part of the Network.

Today we carried out the survey for the measurement of the position of the NCal reference plate points @NE, placed in the SE, NE and NW part of the tower.

Tab.1 reports the VRS coordinates obtained for the points measured (Fig.1), considering NCal_XX_01 as the internal point and NCal_XX_02 as the external one.

Fig.1 to 9 show some photos of the three stations arranged for the survey and the scheme of the points.

The measured positions of the sensors in the End Buildings (30 sensors @WEB eLog49999, 30 sensors @NEB eLog50022) have been marked on the floor by the base plate circle and the ID label (Fig.1 and 2), in order to ease the future repositioning.

Yesterday Nov 23, the positions of the sensors placed inside the North End Building have heen measured and their VRS coordinates calculated (Fig.1 to 5). The pocedure followed has been the same as for WEB (eLog49999).

Tab.1 reports the final result for the 30 sensors of the array. For the correct identification of each sensor, the ID point is the serial number reported on the existing label on top of the cover.

Last Friday Nov 20, the positions of the sensors placed inside the West End Building have heen measured and their VRS coordinates calculated. In total, 30 sensors have been surveyed, together the needed auxiliary reference points (Fig.1).

Tab.1 reports the final result and Fig.2 to Fig.5 some pictures of the survey carried out through the AT403 laser tracker. The measured point and the associated coordinates are referred to the center of the SMR sphere placed on the top of the yellow cover of the sensor (Fig.4 and 5), so about 140÷150 mm above the floor level (Z direction). The normalized offset of SMR center respect its support nest is 25 mm.

For the correct identification of each sensor, the ID point is the serial number reported on the existing label on top of the cover (Fig.3).

Today we completed the survey for the alignment of the ESQB1 optical bench (see also eLog49606 and eLog49680).

Tab.2 reports the final position of the optical bench, individuated by the VRS coordinates of the five considered reference points (Staz05_Final).