13.5. PMRF Range Data
The PMRF Range data file format is the format produced by the PMRF range. The data file contains data in the following format:
All columns in the text file are assumed to be separated by white-space (spaces or tabs). The PRN file can be produced by saving in Excel in the "prn" format, although the resulting file should be examined to ensure that unnecessary white space does occur between the columns.
The PMRF structure starts with four lines of header information (of which the first contains a starting DTG for the serial). It is this DTG which is used as the time offset for the data.
Following the header lines are groups of time stamped position fixes. Each time stamped group begins with a line containing 13 elements. From this line, the 3rd column (GMT) is used to calculate elapsed seconds from the starting DTG. This elapsed time is used as the time value for any points containing only 9 elements (until a new 13-element line is read in).
For 9 element lines (and 13 element lines once the DTG info is read in) the columns are read and used as follows:
Table 13-4. Fields used from PMRF data
Field |
Description |
|---|---|
|
GMT |
Elapsed time in seconds since midnight on DTG contained in first line |
|
Id |
Single text string surrounded by spaces |
|
x |
x-value in yards |
|
y |
y-value in yards |
|
z |
ignored |
|
height |
converted to yards, and used a z-value. |
|
remaining columns |
ignored |
 | Note that only the x,y,z positions from the data are used in Debrief; the velocities and accelerations are ignored. |
 | The data file format does not contain course and speed data, so these are calculated using the range and bearing from the previous point, together with the time difference. This gives values of course and speed calculated as over the ground; which obviously is not the through-the-water values the participants will be experiencing. |