ARMY TM 5-6675-308-12
MARINE CORPS TM 08837A-12/1A
rejecting GPS and entering the known control coordi-
ment, PADS should be driven to the known control
nates, then rejecting the elevation entry. A second
point to be updated prior to attempting to survey.
update would start with GPS, reject of the horizontal,
PADS should be located over the known control
(3)
and update of the vertical using the GPS data. The
point and a non GPS horizontal position update
surveyor should always use known good survey con-
performed. When elevation is cued, the operator
trol over GPS derived data when available.
should exit the update.
h.
After the operator has entered the position and/or
(4)
The GPS receivcr (A) should then be located over
elevation data into the PADS, the system automati-
the SCP. The operator should mark or freeze the
cally tests the difference between the update coordi-
GPS at the SCP and record the FOM, casting,
nates, and his actual PADS position coordinates. If
northing, elevation, and any other data he may wish
the difference (error) is within the built-in calibrated
to review at a later time. This may be recorded as
tolerance parameters, the update is accepted and the
FOMA, EA1, NA1, and ELA1. He should then ini-
CDU will display the update symbology.
tiate another PADS update, using GPS this time,
bypassing the horizontal input, and entering the
i.
When PADS accepts an update and displays such, the
elevation GPS data recorded previously.
system has told the operator that PADS has met the
required specified accuracies needed for that update
The second GPS receiver (B) located at this station
(5)
and all surveyed stations established back to the pre-
does not have to be coincident with the first
vious update. The order of accuracy is based upon the
receiver, but somewhere nearby and setup to oper-
time interval of zero-velocity corrections performed
ate in the NAD 27 CONUS datum. The FOM, east-
during the mission and type of update. To obtain pre-
ing, northing, and elevation should be recorded by
scribed accuracies, using known control bench marks
an assistant in his notebook. This will be FOMB,
for updates, the required zero velocity correction
EB1, NB 1, and ELB1. The value of FOMB should
intervals are shown below:
be recorded in the PADS operator's notebook also.
The PADS and the surveying team have now been
(6)
REQUIRED
REQUIRED TIME
properly prepared and documented to advance on a
ACCURACY
INTERVAL
survey mission. The PADS operator decides to per-
Battalion Survey
10-minute zero-velocity
form a differential GPS update. He would then
Accuracy
corrections
radio the assistant with receiver B, determine that
Division Artillery
5-minute zero-velocity
receiver B had not been moved and the receiver
Accuracy
corrections
operation was still in the same datum as receiver A.
He would then instruct his operator to perform a
A comprehensive example of a mixed first update and
mark on receiver B, noting the FOM, and he would
j.
a differential secondary update is as follows:
do the same on his receiver A.
Assume that the assistant operator notifies the
(7)
(1) PADS is initialized and confined to operation in
PADS operator that the latest set of GPS readings
NAD 27 CONUS datum (Clarke 1866 spheroid),
from receiver B are higher than the first set of read-
unless cycled off and reinitialized. The PADS
ings by
and
The PADS operator
operator has a GPS receiver which has been setup
would then log these values along with the FOM.
to operate in NAD 27 CONUS datum. Several kilo-
The PADS operator would also log his present
meters away, a known survey control station is
position mark data (EA2, NA2, and ELA2) and
available, with good horizontal control, but no
FOM data from receiver A. The PADS operator
vertical (elevation) control. At the known control,
would then perform a differential GPS update for
a second GPS receiver is available.
position and elevation. The casting data to be
- (EA1 - ESCP). The
(2) The operator initializes PADS using SPH 1 (Clarke
entered would be EA2 -
northing data would be corrected by the delta offset
1866) and enters the GPS determined easting,
at the stationary receiver B and difference of SCP
northing, and elevation. On completion of align-
Change 3
3-36.13
Previous Page
