mainTab.html

MAIN Data, coordinates and flags.


Name	Format	Units	Measure	Comments

Keywords

Columns

Key
TIME	Double	s	EPOCH	Integration mid-point
CONFIG_DESCRIPTION_ID	Int			Config-description identifier
FIELD_ID	Int			Field identifier

Data description
SCALE_FACTOR	Float( N_cm, N_bb)			Scale factor(s) for the cross and/or auto-correlations
BIT_SIZE	Int( N_cm, N_bb)			Bit size(s) for the cross and/or auto-correlations

Non-key attributes
INTERVAL	Double	s		Time interval
EXECBLOCK_ID	Int			ExecBlock identifier
SCAN_NUMBER	Int			Scan number
(SUBSCAN_NUMBER)	Int			Subscan number
INTEG_NUMBER	Int			Integration number
STATE_ID	Int( N_a)			State identifier
UVW	Double(3, N_a)	m		UVW coordinates
EXPOSURE	Double( N_bb, N_a)	s		Effective integration time
TIME_CENTROID	Double( N_bb, N_a)	s	EPOCH	Time centroid

Data
DATA_OID	String			Data object identifier

Flag information
FLAG_ANT	Int( N_a)			Flags concerning antennas
FLAG_POL	Int( N_a, N_c)			Flags concerning antennas and polarization
FLAG_BASEBAND	Int( N_a, N_c, N_bb)			Flags concerning antennas, polarization and basebands
FLAG_ROW	Bool			The row flag

Notes: N_bb is the number of basebands (attribute of the CONFIG_DESCRIPTION table), The form of the data object is determined by the attributes of the Data description section in the CONFIG_DESCRIPTION table and by N_c, the number of correlation products, N_f, the number of frequency channels and N_apc which is 1 or 2. These three sizes N_c, N_f and N_apc are known via the identifiers in the DATA_DESCRIPTION_ARRAY collection.

TIME: Mid-point (not centroid) of data interval.
TIME_EXTRA_PREC: Extra time precision
CONFIG_DESCRIPTION_ID: Configuration descriptor identifier (> 0) providing a direct index into the CONFIG_DESCRIPTION sub-table row number. Note that two or more sub-arrays cannot refer to the same CONFIG_DESCRIPTION_ID identifier.
FIELD_ID: Field identifier (> 0)
SCALE_FACTOR: Scaling factors for the auto-correlated data (case N_cm= 1) or for the cross-correlated and auto-correlated data (case N_cm= 2) , this for each of the N_bb basebands, which are stored in the data cell.
BIT_SIZE: The numbers of bytes (2 or 4) for the auto-correlations (case N_cm= 1) or for the auto-correlated and cross-correlated data, this for each of the N_bb basebands, which are stored in the data cell indexed by the DATA_OIDobject identifier.
INTERVAL: Data sampling interval. This is the nominal data interval, it does not include the effects of bad data or partial integration.
EXECBLOCK_ID: This provides access to a row number in the EXECBLOCK_SUMMARY table. This meta coordinate defines the data-base in term of an implicit collection of data blocks.
SCAN_NUMBER: SCAN (ref. ALMA glossary) number. Enumeration relative to the Executing Block.
SUBSCAN_NUMBER: SUBSCAN (ref. ALMA glossary) number.
INTEG_NUMBER: INTEGRATION (ref. ALMA glossary) number. The enumeration is relative to the SUBSCAN (ref. ALMA glossary).
STATE_ID: State identifier (> 0).
UVW: Antenna-based uvw coordinates for the N_a antennas. This is defined at the centroid time TIME_CENTROID .
EXPOSURE: Effective duration of an INTEGRATION (or a SUBINTEG_NUM in the STATE table is > 0).
TIME_CENTROID: Time stamp reflecting the average time the non-blanked data was integrated.
DATA_OID: Reference to the data cell object. It is an object identifier and, as such, is of type String.
FLAG_ANT: Unsigned long int (4-bytes) vector. Each bit corresponds to a specified flagging condition ( e.g. 2² = pointing, 2⁶ = shadowing, ...). When different from zero all data concerning the antenna is affected.
FLAG_POL: Unsigned long int (4-bytes) vector . When different from zero all data concerning the polarization and antenna is invalid (all basebands) (e.g. problem incident before the down converters)
FLAG_BASEBAND: Unsigned long int (4-bytes) vector. When different from zero all data concerning the baseband and antenna is invalid (e.g. problem incident after the down converters)
FLAG_ROW: True if the entire row is flagged.

Table 1:

Definition of Flags - taken from SSR

Flag Word	Bit	Condition

FLAG_ANT	0	Last WVR calibration failed
FLAG_ANT	1	Current WVR hardware defect
FLAG_ANT	2	Last pointing calibration failed
FLAG_ANT	3	Last Temperature Scale Calibration failed
FLAG_ANT	4	Temperature Scale Calibration hardware defect
FLAG_ANT	5	Last WVR calibration failed
FLAG_ANT	6	Shadowing
FLAG_ANT	7	LO1 out of lock
FLAG_ANT	8	No correlation detected on last calibrator
FLAG_ANT	9	Too much decorrelation on last calibrator

FLAG_POL	0	Mixer not operational
FLAG_POL	1	Total power aout of range (pol)
FLAG_POL	2	LO2 out of lock
FLAG_POL	3	Integration totally blanked
FLAG_POL	4	Interference detected
FLAG_POL	7	No correlation detected on last calibrator
FLAG_POL	9	Too much decorrelation on last calibrator

FLAG_BASEBAND	0	Last Temperature Scale Calibration failed, Tsys currently estimated
FLAG_BASEBAND	1	Total power out of range
FLAG_BASEBAND	2	Interference detected
FLAG_BASEBAND	3	No correlation detected on last calibrator
FLAG_BASEBAND	9	Too much decorrelation on last calibrator
FLAG_BASEBAND	4	Integration totally blanked

Remarks:

Sub-arrays: For a given TIME and INTERVAL the presence of different CONFIG_DESCRIPTION_ID attributes reflects different sub-arrays. With CONFIG_DESCRIPTION_ID as a key this table can have rows for different arrays, even if their are not synchronized in time. The EXECBLOCK_SUMMARY table contains an ANTENNA_ID_SET attribute which must at least include all the ANTENNA_ID referenced in the ANTENNA_ARRAY collections used in the Execution Block.
Multi-configurations: In the case of data sets which includes several array configurations, note that there is a CONFIG_NAME in the EXECBLOCK_SUMMARY table; this allows to distinguish easily the case of several sub-arrays and the case of several array configurations.