ARMY TM 9-6675-349-12&P
MARINE CORPS TM 11039A-12&P
4-5. Explanation of Table Entries - Continued
Table 4-2. Operator Preventive Maintenance Checks and Services
Item to be
Check that connections to the vehicle
batteries are tight. If NATO connector is
power cable used, insure connector plugs are secure.
Check for loose screws and level vials not
broken and not cloudy to the point that
stadia scale is not readable.
Porro-Prism Alignment Test
a. Turn on and initialize IPADS.
b. Update IPADS over 4th order or higher
SCP that has a known accurate azimuth.
c. Maneuver vehicle, if required, to
with prism leveled and with theodolite
plumbed over SCP.
d. With theodolite sighted on porro-prism
and instrument initial circle reading set,
measure and record horizontal angle to
EOL. Measure and record distance and
e. Plunge theodolite telescope and repeat
f. Mean the horizontal angles, distances,
and vertical angles obtained in steps d. and
g. Perform a theodolite mark using the
mean horizontal angle, distance, and
vertical angle calculated in step f.
h. The IPADS determined azimuth must
If surveyed azimuth
agree with the surveyed azimuth within
is greater than 0.050
mm porro prism is
Repair of damaged or
unserviceable item is
replacement. Refer to
further detail. If
porro prism is
entire IPADS needs
to be sent to depot