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WERA Raw Data (.USORT)

This is the data format of WERA .USORT / .URFI data which is stored on the Unix/Linux workstation controlling the WERA. This data format supports the permanent operation mode of WERA. Every 128 samples one data set is written to the disk. Files can be combined to longer timeseries as they are acquired in a coherent way.

The file name is generated by the real-time software in the following way:
yyyy-mo-ddd-hh-mm-ss_cod.USORT 

yyyy  year,                e.g. 2008
mo    month,               e.g. 03 (March)
ddd   day within the year, e.g. 80 (18-Mar-2008, leap year)
hh    hour,                e.g. 05
mm    minute,              e.g. 23
ss    second,              e.g. 59
cod   site code,           e.g. gij
The time encoded in the file name and stored in the header is the start time of a coherent 128 sample fraction from the data stream.

The phase of the .USORT / .URFI data is not calibrated. The calibration values found in the receive antenna calibration file /home/wera/etc/calibration.wera (the default) or in the file given in CALF_nnn (defined in params_*.cfg) is read by the subroutine READ_USORT.F and the pase correction is applied after reading the .USORT / .URFI data.
It is essential to pass the correct receive antenna calibration file to READ_USORT. The phase values in the header must be ignored, since they have not been applied.

To distinuish .USORT / .URFI data from other data formats, for

  • .USORT data the header contains the code 'FMUNSO' [Frequency Modulated UNSOrted] and for
  • .URFI data the header contains the code 'FMUNSN' [Frequency Modulated UNSorted Noise].
The data structure of both files is identical. The number of SAMPZ samples is fixed to 128. The total number of samples within a coherent series of .USORT files is given in this field. The start date and time of the data is given in DATIM. The numbers following SS (behind RXOFFSET:) give the seconds of the start time. Due to a vaying number of ANT antennas, and number of NRRANGES range cells, the size and the internal data structure varies. All information needed to adopt the processing programs to this varying data format is taken from the header. The header also contains information on the Mode Bits (description) and the HZMode Bits (description) which have been set during the measurement and the sample rate.

The structure in each data file is as follows: 

|      |                t=1                   |           t=2               |..|     t=SAMPZ      |
| HEAD |--------------------------------------|-----------------------------|..|------------------|
|      | Ant=1          | Ant=2 |...| Ant=ANT | Ant=1 | Ant=2 |...| Ant=ANT |..| .......| Ant=ANT |
|      | RC=1..NRRANGES |  ...  |...|   ...   |  ...  |  ...  |...|   ...   |..| .......|   ...   |
Each sample T(RC,Ant) consists of NRRANGES * ANT complex samples (I,Q) [IEEE REAL*4,IEEE REAL*4].

File_Size [Bytes] = 512 + 8 * NRRANGES * ANT * SAMPZ

The header also contains information on:

Comments to: gurgel@ifm.uni-hamburg.de (Klaus-Werner Gurgel)