numeric form.</p></li>
<li><p>If <code>i</code> is <code>"heading"</code>, <code>"pitch"</code> or <code>"roll"</code>, then
these values are extracted from the
"slow" form in the object (e.g. in <code>headingSlow</code> within
the <code>data</code> slot). In that case, accessing by full name, e.g.
<code>x[["headingSlow"]]</code> retrieves the item as expected, but
<code>x[["heading"]]</code> interpolates to the faster timescale, using
<code><a href="https://rdrr.io/r/stats/approxfun.html" class="external-l