> 4 
ND-4 
565 
(5) PCD analysis 
Payload Correction Data ,giving spacecraft attitude infor- 
mation, contains Euler parameters,Gyro data, Gyro drift data 
and ADS(Angular Displacement Sensor)data. 
By analyzing these data, satellite attitude character- 
istics will be evaluated. 
At first we extracted 512 samples of Gyro data every 64 
msec and 16384 samples of ADS data every 2 msec for each axis. 
Second, applying one dimensional Fourier transform to raw Gyro 
and ADS data, power spectrums are computed. 
Fig.9 shows ADS data for roll,pitch and yaw axis and Fig. 
10 shows power spectrums for each axis,respectively. 
As shown in Fig. 10, one dimensional Fourier transforms 
of ADS data indicates that dominant source of high frequent 
attitude deviation are 7 Hz 13.6 Hz,63 Hz and 68 Hz for roll 
axis and 2.4 Hz ,21 Hz and 63 Hz for pitch axis. On the other 
hand for yaw axis 21 Hz and 68 Hz oscllation are dominant. 
The result of the Fourier analysis sugests that TM and 
MSS scanning mirrors have an important effects on hign frequent 
attitude deviation of spacecraft. 
  
  
ADS ROLL 
urad ADS ROLL 
260 e: : 
2 FM. l 
" 3 byl 
- i 
S | ( i 
240 i 
0 200 400 msec iris 254 3:50... 75 5 100 Hz 
(a) (a) 
urad ADS PITCH 
   
260 | ADS PITCH 
  
  
  
  
  
250 2 m 
E | Ay 
= f 
240 2 
0 200 400 msec : 
(b) | 0 25 50 75 100 
(b) 
urad ADS YAW 
260 laps vau I. AL A 
2 ADAM | 
250 m | an 
= | | | 
= | 
240 
0 (3700 400 msec 0 25 50 75 » 100. Hz 
Fig. 9 ADS data x 
(Chicago, 1982.10.25) Fig. 10 power spectrum of ADS 
(Chicago,1982.10.25)