(IVAR) - Final Report - Strategic Environmental Research and ...

Figure 6-42. eBirdRad display based on the same data as Figure 6-41, with true trail mode
turned off and automatic tracking and track history turned on. The red trails are the positions
(“history”) of the target while it was being tracked; the white label at the head of a track is the
target’s Track ID.
Again, the same strong target that was visible in the preceding four figures was detected and
tracked by the DRP in Figure 6-42. The white label “375” on the track is the target’s Track ID.
We set the eBirdRad display to show a track history of one minute (24 scans at 2.5
seconds/scan), approximately the scan history shown in the BirdRad display. However, as will
be discussed below, the radar tracked this target for 36 scans, or ~1.5 minutes. It’s also
important to note that this target is nearly 3.7 km from the radar, a distance that is near or beyond
the limit of a human observer’s ability to detect the target visually (see Criterion PA4.1, Section
6.1.1.4).
Figure 6-42 also demonstrates that digitally processing radar returns can detect and track targets in
real time that were not visible to the observer of the analog display. The red tails of thirteen more
targets can be seen in this figure – eight with Track IDs indicating they are still being tracked, and
five with red tails but no heads, indicating they are the remnants of tracks that are no longer being
detected.
Another advantage of tracking targets digitally is the wealth of information that can be generated
about the target in real time. Figure 6-43 and Figure 6-44 display some of the data that are
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