IMAGENEX DT101Xi, Technical Manual

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It is recommended to repeat the exercise using various cross profiles and the average derived and applied.
The Surveyor should verify the sign of the roll corrections. Hypack automatically corrects for the sign and
the reported pitch correction should be applied as is. Other patch test software may require an inversion of
the sign and the Surveyor must be aware of this.
4.2.2. Pitch
A pair of reciprocal lines, run over a feature / slope at the same speed, will be used to assess the pitch
correction.
Again, the deepest section of survey area should be selected as the error’s visibility increases
with depth.
Figure 4-5 Pitch lines
The pitch correction is described by the following equation (Eq 16):
α = tan
−1
(
𝑑
𝑎
/2
𝑑𝑒𝑝𝑡ℎ
)
(Eq 16)
Where
α = Pitch offset (deg)
d
a
= Along-track displacement (m)
depth = Water depth (m)
Same line, reciprocal
headings