July 26, 2006
ALMA Pointing
20
Accelerometer Measurements of BUS Pointing Errors
0.07
0.14
900
Encoder Error
0.23±0.01
0.8±0.5
1
Mosaicking at 0.05 deg/s
AEC a
(arcsec)
VertexRSI a
(arcsec)
0.50±0.03
1.70±0.07
1
OTF at 0.5 deg/s
0.50±0.13±0.11±0.02
0.94±0.26±0.20±0.05
900
Tracking With Wind
0.29±0.09±0.05
0.58±0.15±0.08
10
Tracking With Wind
0.22±0.08
0.47±0.11
10
Sidereal Tracking (no wind)
0.45±0.10±0.11±0.02
0.81±0.24±0.20±0.05
900
Stationary Pointing (9 m/s wind)
Dt
(sec)
Measurement Condition
a Contributions to each quoted value are defined, respectively, as pointing Variation, spread, wind power spectrum
  uncertainty, and wind extrapolarion uncertainty.
Both antennas ended-up with a 13-term pointing model.