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Next,Fig.2 shows a graph of-the DC drift for the 
vibration gyro. In this experiment ,the output of the 
vibration gyro was measured every ten minutes for 120 
minutes in a stationary state.For the change in the 
output due to elapsed time,0 to about 20mV was 
observed,and it was confirmed that it is within the 
range of the DC drift specified in the performance data 
in the vibration gyro used. 
  
8.822 
9.92 ED TO 
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8.0167 
9.0144 
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9.914 
8.008 1 
9. 006 1 
9.004] . 
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10 29 30 40 50 69 70 £0 94 1088 110 120 
TIME(MIN) 
OUTPUT VOLTAGE (V) 
  
  
  
  
  
Eis:.2 1C adrift 
Fig.3 shows a graph for measurement result for the 
temperature drift.This experiment was performed at 
temperatures within a range of 0 degree to about 35 
degrees assuming the temperatures which can be 
usually considered.First,ice and water were put into 
expanded styrene to make the water temperature 
constant at O degree.and then a vibration gyro with 
constant output was wrapped in vinyl and was put into 
the ice and water to measure,after a while.the surface 
temperature of the vibration gyro.For hot water,the 
surface temperature of the vibration gyro in the hot 
water was measured similarly. 
  
  
  
  
mor d m 
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x 9 
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> 0.015 
End Zi 
o 8 
t; 0.0054 
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0 B m 
BE HD m "rt ru = 
TEMPERATUREC'C) 
Fig.3 Temerature drift 
When a vibration gyro was put in the ice and water,the 
output rose 0.019V to 0.029V(measured three times) as 
compared with the output (2.572V) at normal 
temperature (26.0 C),and the rate of change was 
0.7396 to 1.1396 (0.019V/2.572V to 0.019V/2.572V).Also 
when it was put into hot water,the output rose 0.004V 
to 0.010V as compared with the output(2.518V) at 
normal temperature,the rate of change being 0.15% to 
0.39%(0.004V/2.518V to 0.010V/2.518V) Either 
temperature had error of about 1%. 
From the foregoing experimental result,the DC driftfor 
the vibration gyro changes 10mV at maximum per ten 
minutes from Fig.2,but it comes to about 13. when 
converted into angle.In this reserch,therefore,the 
experiment was performed so that the measurement is 
started in five minutes after the switch is finished 
within about 1 to 2 minutes, and the observed value is 
not greatly affected by the DC drift as an error. 
Also.the temperature drift changes 0.006V at 
maximum within a range of about *=8°C from the 
temperature during the measurement. This voltage 
variation produces an error of about 40'.In the 
experiment of this reserch,it was performed where 
there is no temperature change more than 8C 
during measurement so that it is not affected by the 
temperature drift as much as possible.In this respect, it 
is necessary to take into consideration the effect by 
these drifts during measurement for a long period of 
time. 
Incidentally,since this system uses three gyros 
altogether graphs for the respective gyros are shown. 
2.2Performance of measuring angular speed 
In the experiment,a vibration gyro was placed on a 
turn table,and the output voltage when the rotational 
speed was changed to 90 was measured.The graph in 
Fig.4 shows the relation between the elapsed time 
required to rotate 90° and angle.From this figure, the 
converted angles when the 90 rotation was 
performed at each rotational speed are 90° 2927" at 9’ 
[sec,90 4°57" at 16 /sec,and 89 2912" at 40 /sec as 
shown by mark 6 in the figure,and the error at 90 
was about 3-196. 
  
  
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vi 90 e e —- 
e, 8^ S e 
TR e. wii ° We X . 
Se | MOT VSEL 16vsEe 779" s86 
  
  
  
TIME(1/208) 
Fig.4 Relation between elapsed times 
and turned angle 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B1. Vienna 1996