User manual

Table Of Contents
If field data is unavailable for the spin test, use a hand compass to sight bearings and
calculate the offsets and scale factors with the pre- or post-deployment spin test measurements
that you used when correcting the compass measurements for angular bias.
NOTE
If possible, conduct the spin test away from the magnetic fields of buildings, docks, and ships.
Spin Test
To perform a spin test, complete the following steps:
1. Run the communications cable from the serial communications connector up
through the hole in the bottom rib of the MMP frame and out through the oval
hole in the back of the skin. Hold the profiler vertically, balanced on the lower
faired end cap (keep the MMP vertical while making measurements).
2. Use the ‘Bench Test Utility’ menu options to begin scrolling tilt and compass
measurements and log the output with the Crosscut file capture utility (you can
also use the ACM communications pass-through and manually trigger the
measurements as needed).
3. Slowly turn the profiler through one or more complete turns (begin with the sting
pointed north and rotate towards the east, if possible). This portion of the spin
test data is also used to calculate the offsets and scale factors as described in the
previous section.
4. To collect the data for compass measurements associated with known headings
of the sting, carefully and accurately align the sting with magnetic north (these
compass measurements are needed to remove the bias angle which is explained
in the next section).
NOTE
For more accurate measurements, place the hand compass as close to the ACM compass as
possible (for example, rest the compass on top of the profiler).
5. Record the measurements for ten seconds or more.
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