Figure 4-2 Coordinate system and sensor 
4.1.2 Handy type inertial survey device 
This device was manufactured so that measuring in a 
difficult place (place with the height difference, place 
where there are many violent ups and downs, etc.) to 
measure in the monocycle type might be possible. The 
battery etc. was made possible to be carried on the back 
like a monocycle type. This device can be not only mov 
able anywhere but also accurately centered in comparison 
with the monocycle type if there is space where one per 
son can pass in comparison with the monocycle type. 
However, when the measurement was done, axis x and 
axis y of the device block were needed to be horizontal 
and axis z to be perpendicular to the ground respectively 
as condition for an initialization, and this initialization was 
easily able to be done comparatively in the monocycle 
type so far. However, a special plinth was used so as to 
make the initialization because it was difficult for this de 
vice to satisfy the initialization as the device was handled 
by person's hand. 
4.2.1 Traverse survey(measurement of plane position) 
4.2 Traverse survey and leveling with monocycle 
type inertial device (Measurement of plane position and 
difference of elevation) 
The traverse survey and the leveling were done with a 
monocycle type inertial survey device. As the accele 
rometer and the gyroscope were installed to become three 
axis orthogonalization, the traverse survey can determine 
the horizontal position of the survey point by the value of 
axis X and axis Y. The leveling calculates height with axis 
Z, and the horizontal position is obtained in the value of the 
resultant of the axis XY. That is, as three dimension posi 
tion is calculated, this device can calculate the result of the 
traverse survey and the leveling at the same time. In this 
initialization, plane x-y is set horizontal against the ground 
level. 
In the experiment, four traverse points were provided on 
brick pavement at Chiba Instituteof Technology so that a 
guadrilateral of about 30m x about 15m is formed. Fig 
ure 4-3 shows the outline of the experiment place. 
Figure 4-5 shows the result of the traverse survey with an 
inertial device. In this figure, the traverse point is a value 
measured with the Theodolite and the Electronic distance 
meter. The movement was in order of A-»B—>C—*D—>A. 
The result can be said to be not too good as a whole. We 
think that the reason why such a result was found is that a 
time error was accumulated because the movement for 
return from point A to point A was so rapid. Additionally, it 
is thought that the reason is that initialization (The inertial 
block was horizontally set.) was not done accurately. Fig 
ure 4-4 shows the difference of the coordinate system of 
the initialization and the movement. If initialization is not 
accurately done (Initial posture inclines.), the value output 
from the inclined amount of accelerometer becomes small. 
When the value of accelerometer is analyzed (integration), 
the average value at geostationary is subtracted as a bias 
value. Therefore, if initial posture inclines the output value 
which is possible to be inclined is subtracted as a bias 
value as well. Therefore, the error is caused because the 
analysis was done by using the value outputted according 
to the inclination. Moreover, when inclined, the coordinate 
transformation value reaches the value of the direction of 
each axis in the inclined coordinate system. Therefore, it is 
thought that the gap in the value with the traverse point is 
caused because they cannot be compared under the 
same condition when they are compared with the traverse 
point. As coordinates conversion is very much influenced 
with the value by the gyro, the value of the acceleration by 
which coordinates conversion was carried out will become 
not so good if data obtained from the gyro is not so accu 
rate. 
6B-5-3 
WS««?* 1 - 
H fig ÿ \ ala ‘ m «albi 
'