6B-5-4
Axis Z
: Ideal Initialization
: Actual initialization
Axis X
Ü.
Axis X'
Figure 4-4 Difference of coordinate system
-15 -10 -5 0 5 10 15
E-W direction distance[m]
■X—Traverse point —■—TEST1
—TEST2 —♦— TEST3
-•— TEST4 —©— TEST5
Figure 4-5 Result of traverse survey
4.2.2 Leveling(measurement of difference of elevation )
In this figure, the traverse point is a value measured with
the automatic level. The gap (error) with the survey point is
larger than that of the traverse survey. Here, the amount of
the movement of the vertical direction to the movement
time is smaller compared with the amount of the move
ment of horizontal direction to the movement time. There
fore, it is thought that the error of the leveling is larger than
that of the traverse survey. Figure 4-6 shows the result of
the movement tracks. Movement was in order as A—>B—>
C-»D—>A. When moving from point A to B, actual move
ment leaves at point A, then at once descends through the
difference of elevation of about 30cm, and moves at a
smooth place up to point B afterwards. According to tracks
by the inertial survey of Figure 4-6, it is closer to actual
movement in the place descending by about 30cm, but the
part where it moves at a smooth place until reaching point
B accumulates the error, and the tracks are quite different
from actual movement.
-10 0 10 20 30 40
N-S direction distancefm]
X Traverse point
■
-TESTI
-A-TEST2
-TEST3
—TEST4
—e-
-TEST5
Figure 4-6 Leveling (movement tracks)
The accumulation of the error is a little in TEST4 and
TEST5, because a straight line distance is short, even
though the movement from point B to C is of an almost
smooth place.
In the movement from point C to D, it actually leaves at
point C and moves at a smooth place, then goes up by
about 30cm, and moves some meters to reach point D.
According to tracks of Figure 8 we are supposed to move
at a smooth place but as the error is accumulated, the
tracks are descended. However, the tracks are showing
almost an actual motion only for the place going up.
The movement from point D to A' (point which returned to
point A) is the same as the one from point B to C, and
moved distance is of the straight line is short and the ac
cumulation of the error is small.
From the above-mentioned point of view, it is thought that
if the place with some difference of elevation is moved
without taking much time in the leveling by the inertial
survey, a value close to an actual one can be calculated.
However, it is understood that the error accumulates when
time is taken for measurement at the place where there
are not so many differences of elevation and a preferable
result is not obtained.