Maintenance - Maretron GPS200-01 User Manual

GPS200 User's Manual
this magnitude are not common but they do exist. Declination anomalies of the order of 3 or 4
degrees are not uncommon but are of small spatial extent and are relatively isolated.
On land, spatial anomalies are produced by mountain ranges, ore deposits, ground struck by
lightning, geological faults, and cultural features such as trains, planes, tanks, railroad tracks,
power lines, etc. The corresponding deviations are usually smaller at sea, and decrease with
increasing altitude of an aircraft or spacecraft. In ocean areas, these anomalies occur most
frequently along continental margins, near seamounts, and near ocean ridges, trenches, and
fault zones, particularly those of volcanic origin. Ships and submarines are also sources of
magnetic anomalies in the ocean.
However, from a global main field perspective, the declination (D), inclination (I), and grid
variation (GV) RMS errors of WMM are estimated to be less than 1.0° at the Earth's surface over
the entire 5-year life span of the model. Also, the RMS errors at the Earth's surface horizontal
intensity (H), the vertical component (Z), and the total intensity (F) of WMM are estimated to be
well below 200 nT over the entire 5-year life of the model. Thus, the WMM meets and exceeds
the accuracy requirements detailed in MIL-W-89500 (Defense Mapping Agency, 1993) for the
entire life span of
http://www.ngdc.noaa.gov/geomag/WMM/DoDWMM.shtml.

4 Maintenance

Regular maintenance is important to ensure continued proper operation of the Maretron
GPS200. Perform the following tasks periodically:
 Clean the unit with a soft cloth. Do not use chemical cleaners as they may remove paint
or markings or may corrode the GPS200 enclosure or seals. Do not use any cleaners
containing acetone, as they will deteriorate the plastic enclosure.
 Ensure that the unit is mounted securely and cannot be moved relative to the mounting
surface. If the unit is loose, tighten the mounting screws.
 Check the security of the cable connected to the NMEA 2000
necessary.
Page 6
the model. To learn more about the WWM, please visit
®
interface and tighten if
Revision 1.3