Site Information for Zegveld

ZEGV (Zegveld IGRS)

Marker ID: 13543M001
Operator: TUD/CITG/GRS
Log file: zegv00nld_20260514.log

Receiver

Installed	week/d doy	Removed	week/d doy	Receiver type	S/N	Firmware
2020-02-07T09:45Z	2091/5 038	2020-02-07T20:40Z	2091/5 038	SEPT POLARX5	3046503	5.3.1
2020-02-07T20:40Z	2091/5 038	2023-04-17T06:39Z	2258/1 107	SEPT POLARX5	3046503	5.3.2
2023-04-17T06:39Z	2258/1 107	2026-05-14T12:42Z	2418/4 134	SEPT POLARX5	3046503	5.5.0
2026-05-14T12:42Z	2418/4 134			SEPT POLARX5	3046503	5.7.0

Antenna

Installed	week/d doy	Removed	week/d doy	Antenna type	Dome	S/N	Height	Antenna calibration
2020-01-22T10:00Z	2089/3 022			SEPCHOKE_B3E6	SPKE	5461	0.0000

External Frequency

Installed	week/d doy	Removed	week/d doy	Ext. Frequency type
2020-02-07T09:45Z	2091/5 038			INTERNAL

Notes

2020-01-22T10:00Z 2089/3 022 -

The GNSS instrument mechanically connected to two 90 cm trihedral corner reflectors for co-locating (In)SAR ascending and descending radar satellite tracks. The GNSS monument itself consists of a SECO mount, on top of a 2.5 m heigh 8 cm diameter stainless steel pipe, with a 35 cm square strudded footplate. On each side, a 90 cm corner reflector for ascending and descending InSAR tracks is attached. 1.42 m below the GNSS monument a GCP for LIDAR measurements (the top plate of the IGRS) is present. The whole assembly is mounted on a concrete block fixed to 3 steel/grouted 11.5 long foundation piles to sub-surface sand deposit. On top of the sand layer is a 8 m peat toplayer. The top plate of the IGRS is 1.122 meter above the concrete block, the GNSS monument is 1.416 m above the top-plate (LIDAR GCP).

2026-05-20T08:13Z 2419/3 140 - 2026-06-01T09:01Z 2421/1 152

Between May 20th and June 1st, 2026, a concrete block was placed, without authorization, on the top plate of the IGRS. For a picture see concrete block with dimensions. The tapered concrete block weighted 39.2 kg, with dimensions 24x24 cm at the bottom, 15x15cm at the top, and 35.5cm height. It was placed on the top plate, South of the pole, with the center of the block at 0.57 m from the center of the pole. The block was placed on the top-plate on May 20th, around 10:13 LT. On June 1st, around 11:01 LT the block was removed and placed below the IGRS on the concrete foundation (where it doesn't affect the monument stability). Measurements from an inclinometer, mounted on the pole just below the top-plate (at a height of about 1 m above the concrete foundation), showed a tilt increase of roughly 0.035 deg, equivalent to approximately 0.6 mm displacement of the top-plate towards the South during this period. Measurements from an inclinometer at the top of the pole showed an inceased tilt towards South of 0.02 deg, equivalent to approx. 0.7 mm (considering a pole length of 2 m). Results from the inclinometer measurements are provisional and subject to change.

2026-06-01T09:03Z 2421/1 152 - 2026-06-01T09:35Z 2421/1 152

Static load bearing and shaking tests were performed to obtain the response of the inclinometers and effect on the stability of the IGRS construction.