29.1.1 DasAcquisition

Topic Version	1	Published	12/09/2016	Topic Change History
For Standard	PRODML v2.0
Type:	Group		Stereotype:	«XSDcomplexType»

Contains metadata about the DAS acquisition common to the various types of data acquired during the acquisition, which includes DAS measurement instrument data, fiber optical path, time zone, and core acquisition settings like pulse rate and gauge length, measurement start time and whether or not this was a triggered measurement.

Table 29.1.1-1 Attributes
Name	Type	Notes
AcquisitionDescription	String2000	Free format description of the acquired DAS data.
AcquisitionId	UuidString	A universally unique identifier (UUID) for an instance of a DAS acquisition.
DasInstrumentBox	DasInstrumentBox	Description of the measurement instrument. Often referred to as interrogator unit or IU.
FacilityId	String64	This is a human-readable name for the facility or facilities which this acquisition is measuring.
GaugeLength	LengthMeasure	A distance (length along the fiber) which the DAS interrogator unit manufacturer designs and implements by hardware or software to affect the interrogator unit spatial resolution.
GaugeLengthUnit	String64	Only required in an HDF5 (H5) file to record the unit of measure of the gauge length.
MaximumFrequency	FrequencyMeasure	The maximum signal frequency a measurement instrument can provide as specified by the vendor. This is the Nyquist frequency (or some fraction thereof) of PulseRate.
MeasurementStartTime	TimeStamp	The time-date specification of the beginning of a data ‘sample’ in a ‘time series’ in ISO 8601 compatible format. This is typically a GPS-locked time measurement.
MinimumFrequency	FrequencyMeasure	The minimum signal frequency a measurement instrument can provide as specified by the vendor.
NumberOfLoci	NonNegativeLong	The total number of ‘loci’ (acoustic sample points) acquired by the measurement instrument in a single ‘scan’ of the fiber.
OpticalPath	FiberOpticalPath	Description of the fiber optical path. A fiber optical path consists of a series of fibers, connectors, etc. together forming the path for the light pulse emitted from the measurement instrument.
PulseRate	FrequencyMeasure	The rate at which the interrogator unit interrogates the fiber sensor. For most interrogators, this element is informally known as the ‘pulse rate’.
PulseWidth	TimeMeasure	The width of the ‘pulse’ sent down the fiber.
PulseWidthUnit	String64	Only required in an HDF5 (H5) file to record the unit of measure of the pulse width. Default is nanoseconds (ns).
SpatialSamplingInterval	LengthMeasure	The separation between two consecutive ‘spatial sample’ points on the fiber at which the signal is measured. Not to be confused with ‘spatial resolution’.
SpatialSamplingIntervalUnit	String64	Only required in an HDF5 (H5) file to record the unit of measure of the sampling interval.
StartLocusIndex	NonNegativeLong	The first ‘locus’ acquired by the interrogator unit. Where ‘Locus Index 0’ is the acoustic sample point at the connector of the measurement instrument.
TriggeredMeasurement	boolean	Measurement for an acquisition that requires synchronization between a transmitting source (Tx) and a recording (Rx) measurement system. It must be recorded for every measurement regardless of what application it will serve.
VendorCode	BusinessAssociate	Description of the vendor providing the DAS data acquisition service. Note that in the HDF5 (H5) file, this is a single string describing vendor name and some additional information that the vendor deems relevant, e.g., ‘VendorX FBE data version 2.3’.

Table 29.1.1-2 Associations
Association	Notes
From: DasAcquisition. To: AbstractObject Generalization
From: DasAcquisition.Custom 0..1To: DasCustom Association
From: DasAcquisition.Raw 0..*To: DasRaw Association
From: DasAcquisition.Calibration 0..*To: DasCalibration Association
From: DasAcquisition.Processed 0..1To: DasProcessed Association