HDF5
HDF5 is a file format that allows data structures to be stored in an efficient way. The simulator contains a module called h5writer.py to store the ACMs (array covariance matrices) it generates in said format. This module uses an external Python library called h5py to create these files. For detailed information on said library and the HDF5-format visit https://docs.h5py.org/en/stable/
The internal structure of the hdf5-file is shown below. There are further attributes in each group and dataset to define units. There are also source descriptions and names in the form of attributes within the group for each source. The latter are identical to the group name.
File structure:
/commit
Attribute to denote the software version./creation_date_utc
Attribute of the file creation timestamp in UTC.
- /acms
Group for the ACM datasets.
- /noise
Group containing the noise data.
- /<id>
Usually just ID 0.
- /<noise source>
For example LNA, atmosphere, telescope./frequencies
List of frequencies simulated, in GHz./acm
XYZ array. X is the frequency as in /frequencies. Y and Z is the ACM.- /rfi
Group containing the RFI data.
- /<id>
One unique ID for each RFI source./frequencies
List of frequencies simulated, in GHz./coordinates
The phi, theta coordinate of the RFI source./acm
XYZ array. X is the frequency as in /frequencies. Y and Z is the ACM.- /signal
Group containing the astronomical signal data.
- /<id>
One unique ID per astro source./frequencies
List of frequencies simulated, in GHz./ppa
source polarization/acm
XYZ array. X is the frequency as in /frequencies. Y and Z is the ACM.- /array
Group for the PAF geometry data./antenna_matching
Impedance./antenna_return_loss
Loss in front of LNA, for example RFI filter./element_ids
List of IDs to identify the antennas./element_polarisations
List of polarizations of each antenna./element_positions
List of XY positions of every antenna on the plane of the PAF./geometry
The geometry of the antenna array, for example square, honeycomb, etc./radius
Maximum radius of the PAF plane. All antennas are within it./spacing
Antenna spacing on the PAF plane.- /telescope
Group for telescope information./elevation
Altitude angle of telescope relative to the ground. Important for spill-over./name
Name of the telescope, for example Effelsberg.