July 26, 2006
ALMA Pointing
10
Accelerometer System
±10 Endevco Model 86 Seismic Accelerometers
±2/3 Axis Configuration
±Sensitivity over 0.1 to 30 Hz (10 to 0.03 sec) with accuracy several mm to 10 nm
±Extended to 0.001 Hz (15 minutes) using wind power spectrum extrapolation
±Coupled with Sonic Anemometer Measurements
CREATOR: XV Version 3.10a Rev: 12/29/94 (PNG patch 1.2) Quality = 100, Smoothing = 0
PSD plot: Averaged over 0.3-2 Hz as a function of wind direction as viewed from the sonic anemometer.
PSD plot: Red = Measured turbulent component, Blue = Gaussian obstruction components, Green = Multi-gaussian fit.
PSD plot: Peaks are AEC (125), VertexRSI (160), Mitsubishi (210), VLA Control Building (250).