Database Overview

The tower properties data is stored in a single JSON file, which contains information about the coordinates of the power plant, the receiver, and all calibration targets. This file primarily focuses on the coordinates that define each calibration target and the receiver. It also includes details about the type of receiver installed at the site. These coordinates are illustrated in the image below.

Calibration Images

The calibration images are saved as PNG files and multiple formats are available. Below are examples from Heliostat AA23:

Image Type	Description	Example
Raw Image	Original calibration image showing one or more targets, unprocessed and possibly skewed.
Cropped Image	Grayscale image showing only the relevant calibration target, cropped from the raw image.
Flux Image	Image derived with the UTIS model, showing relative flux distribution and background separation.
Flux Centered Image	Processed flux image centered around the focal spot and scaled to a uniform size.

Calibration Properties

Each calibration image has an associated JSON file containing properties information for this image. These properties include themotor positions, the target name,focal spot centroids, and the sun elevation &sun azimuth using the south-based azimuth system.

Results Summary

Each deflectometry measurement includes a PDF summary containing general information, graphs, and a results overview. While not critical for plant operation, it gives insight into the measurement campaign.

Measured Surfaces

The core deflectometry data is a HDF5 contains measuredsurface points and corresponding surface normals for each facet on the heliostat. To account for missing data during acquisition, we provide both a raw and filled HDF5, whereby in the filled HDF5 file missing points are replaced with ideal data points generated by the QDec_2014-01 system.

For each heliostat a JSON file containing heliostat properties is provided. This data includes thegeographic position, the physical dimensions, information on the initial orientationsand any pastrenovation history. Furthermore, detailed information on the facet and kinematic properties are provided.

Facet Properties

This information describes the reflective mirror configuration, by describing the canting type, the number of facets. Each facet has a translation_vector and canting direction vectors (canting_e, canting_n) which are shown in the image below and define its position and orientation.

Kinematic Properties

All heliostats use a two-actuator kinematic structure, allowing movement in two directions. These actuators introduce mechanicaloffsets that are described via translation vectors for three components: joint one, joint two, and the concentrator. These translations vectors point in the east, north, and up directions and are shown on the image below.

Finally, the actual actuators have multipleactuator parameters which are defined in the table below and highlighted in the final reference image.

Parameter Name	Description	Reference
type_axis	Type of actuator motion (e.g., linear, rotary).	--
min_increment	Minimum step the actuator can move.	--
max_increment	Maximum actuator increment range.	--
increment	Total number of increments per full stroke.	--
offset_shift	Adjustment in the actuator’s zero position.	(4) in following reference image
initial_stroke_length	Initial extension length of the actuator.	(5) in following reference image
offset	Physical offset from the actuator axis to the pivot.	(3) in following reference image
pivot_radius	Radius from the pivot center to actuator anchor.	(2) in following reference image
radius_shift	Shift in pivot radius due to geometry.	(1) in following reference image
clockwise_axis_movement	Boolean indicating movement direction: 0 = counterclockwise, 1 = clockwise.	--
initial_angle	Starting angular position.	--
min_movement_angle	Minimum angular range allowed.	--
max_movement_angle	Maximum angular range allowed.	--
movement_speed	Speed at which actuator moves.	--

Meteorological weather data is provided from a weather station at the Jülich tower at a 1 s resolution and from the DWD weather station Aachen-Orsbach with the ID 1500 at a 1 min or 1 h resolution.

The weather data is saved in the HDF5 format. For the Jülich tower there is one HDF5 file per month of recorded data whilst all data from the DWD weather station is in one single HDF5 file.

An overview of the weather variables recorded and associated data is provided in the table below.

Variable Name	Description	Units	Temporal Resolution	Jülich	DWD
atmospheric_pressure	Atmospheric pressure.	hPa	1 s	✓
cloud_cover_1h	Total cloud cover.	fraction (1/8)	1 h		✓
diffuse_irradiation	Diffuse part of the solar irradiance.	W/m²	1 s	✓
direct_irradiation	Direct part of the solar irradiance.	W/m²	1 s	✓
global_irradiation	Total (diffuse + direct) solar irradiance.	W/m²	1 s	✓
global_radiation_10min	Sum of solar incoming radiation.	J/cm²	10 min		✓
humidity_1h	The humidity.	%	1 h		✓
long_wave_radiation_10min	Sum of longwave downward radiation.	J/cm²	10 min		✓
precipitation	Rainfall amount.	mm/day	1 s	✓
pressure_vapor_1h	Vapor pressure.	hPa	1 h		✓
relative_humidity	Relative humidity.	%	1 s	✓
short_wave_radiation_10min	Diffuse solar radiation.	J/cm²	10 min		✓
sunshine_duration_10min	Duration of sunshine.	h	10 min		✓
temperature	Ambient air temperature.	°C	1 s	✓
temperature_diffuse	Temperature related to diffuse irradiance.	°C	1 s	✓
temperature_direct	Temperature related to direct irradiance.	°C	1 s	✓
temperature_global	Temperature related to global irradiance.	°C	1 s	✓
time	Timestamps.	-	1 s	✓
visibility_range_1h	Range of visibility.	m	1 h		✓
weather_type_1h	Encoded weather condition type.	-	1 h		✓
wind_direction	Wind direction.	Degrees (0–360)	1 s	✓
wind_speed	Wind speed.	m/s	1 s	✓