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4 Data acquisition
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4.1 Planning the survey
Prior to radar data acquisition, thoroughly planning of the survey should be done. It’s advisable to
conduct the data acquisition in straight lines, so called swaths, whenever possible. The MIRA system
does not require straight swaths but the positioning errors will be less and the coverage of the area will
be easier managed if the geometry is kept simple, see an example in Figure 4.1.
Utilises are best detected if the measurement swaths are made in the same direction as the utilises
are located. If the direction is unknown it is best to measure in two directions and look at the two
different projects separately in rSlicer.
Fig. 4.1
. Example of measurement swaths for a smaller investigation area where all swaths are made
in the same direction, from west to east.
It’s essential to ensure proper positioning over the whole area and this includes line of sight from the
Total station to the radar array, if a total station is used. However, most modern Total station can
handle the fact that the signal is interrupted (due to smaller trees etc) for a short while.
Most often it is also good to have the radio-link at some height above ground.
Planning for how many different Total station positions as well as mapping of reference points
(buildings, man-holes, roads etc.) is preferably done prior to radar data acquisitions. In Fig. 4.2 an
example is shown with marked roads (red lines) and trees (A).
