YSI SonTek ADVField

Acoustic Doppler Velocimeter Principles of Operation (September 1, 2001)
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SonTek/YSI Technical Notes
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SonTek/YSI, Inc.
Acoustic Doppler Velocimeter Principles of Operation
Table of Contents
Page
1. Introduction...............................................................................................................1
2. The Doppler Shift and Bistatic Current Meters.....................................................1
3. Beam Geometry and 3D Velocity Measurements...................................................2
4. Sampling Volume Definition....................................................................................3
5. Pulse-Coherent Processing ....................................................................................... 4
6. ADV Data................................................................................................................... 5
6.1. Velocity ...................................................................................................................5
6.1.1. Velocity Range ................................................................................................ 5
6.1.2. Sampling.......................................................................................................... 6
6.1.3. Short Term Uncertainty (Noise)...................................................................... 6
6.1.4. Accuracy.......................................................................................................... 6
6.2. Signal Strength ........................................................................................................ 7
6.3. Correlation Coefficient............................................................................................ 7
7. Special Considerations.............................................................................................. 8
7.1. Alternate Probe Configurations............................................................................... 8
7.2. Sound Speed............................................................................................................ 9
7.3. Near-Boundary Measurements.............................................................................. 10
7.4. Reduced Sampling Volume................................................................................... 12
7.5. Low Flow Measurements ...................................................................................... 12