Vaisala IRIS - Page 164

Pile Product (2X Zoom example)
This shows the result of correlation step in which the time DWELL points are "piled". Since
each trial wind produces a dierent pile product, the diagnostic output only shows the pile
product for the first trial wind. In this case the result for the particular trial wind of 210° and
12 m/s (39 ft 4 in) was selected by inputting only these values into the limits for the speed
and direction ranges.
The results show that the coherent streaks of echo as seen in the DWELL time display are
eectively "piled-up" by this trial wind, while background noise produces only weak values.
Not all streaks produce a large value since the targets may be moving at a dierent velocity.
This is why it is important to use a spectrum of trial winds.
IRIS Product and Display User Guide M211319EN-H
162 RESTRICTED