Influence of Antenna Pattern Distortions

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Influence of Antenna Pattern Distortions on
Surface Current Data collected by a CODAR
HF-Radar System
Josh T. Kohut Scott M. Glenn Donald E.
Barrick
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(No Transcript)
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Radial Velocity Map
Brant Beach Site
Brigantine Site
Moored ADCP
25 km
A
25 cm/s
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Radial Velocity Map
Brant Beach Site
Brigantine Site
Location
Moored ADCP

• Range
• Bearing

25 km
A
25 cm/s
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AntennaPatterns
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Role of Antenna Patterns in Signal Direction
Determination
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Role of Antenna Patterns in Signal Direction
Determination
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Measured vs. Ideal Antenna Patterns
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Calibration Runs
Ground Plane
Run Number
Environment
Antenna
Date
1 8ft Brigantine Brigantine
10/99
2 4ft Brigantine Brigantine
10/99
3 8ft Brant Beach Brant Beach
10/99
4 4ft Brant Beach Brant Beach
10/99
5 4ft Brant Beach Brant Beach
09/00
6 4ft Brant Beach Brigantine
09/00
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Calibration Runs
Ground Plane
Run Number
Environment
Antenna
Date
1 8ft Brigantine Brigantine
10/99
2 4ft Brigantine Brigantine
10/99
3 8ft Brant Beach Brant Beach
10/99
4 4ft Brant Beach Brant Beach
10/99
5 4ft Brant Beach Brant Beach
09/00
6 4ft Brant Beach Brigantine
09/00
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Measured Brant Beach Antenna Patterns
8 ft Ground Plane
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Measured Brant Beach Antenna Patterns
8 ft Ground Plane
4 ft Ground Plane
0.5 0.4 0.3 0.2 0.1 0.0 -0.1 -0.2 -0.3 -0.4 -0.5
40 60 80 100 120 140 160
180 200 220
40 60 80 100 120 140 160
180 200 220
Angle (Degrees From True North)
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Calibration Runs
Ground Plane
Run Number
Environment
Antenna
Date
1 8ft Brigantine Brigantine
10/99
2 4ft Brigantine Brigantine
10/99
3 8ft Brant Beach Brant Beach
10/99
4 4ft Brant Beach Brant Beach
10/99
5 4ft Brant Beach Brant Beach
09/00
6 4ft Brant Beach Brigantine
09/00
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Measured Antenna Patterns (4 ft)
Brant Beach, NJ
Brigantine, NJ
0.5 0.4 0.3 0.2 0.1 0.0 -0.1 -0.2 -0.3 -0.4 -0.5
40 60 80 100 120 140 160
180 200 220
40 60 80 100 120 140 160
180 200 220
Angle (Degrees From True North)
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Calibration Runs
Ground Plane
Run Number
Environment
Antenna
Date
1 8ft Brigantine Brigantine
10/99
2 4ft Brigantine Brigantine
10/99
3 8ft Brant Beach Brant Beach
10/99
4 4ft Brant Beach Brant Beach
10/99
5 4ft Brant Beach Brant Beach
09/00
6 4ft Brant Beach Brigantine
09/00
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Measured Antenna B Patterns
Brant Beach, NJ
Brigantine, NJ
0.5 0.4 0.3 0.2 0.1 0.0 -0.1 -0.2 -0.3 -0.4 -0.5
40 60 80 100 120 140 160
180 200 220
40 60 80 100 120 140 160
180 200 220
Angle (Degrees From True North)
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Measured Antenna Patterns (4 ft)
Antenna A
Antenna B
0.5 0.4 0.3 0.2 0.1 0.0 -0.1 -0.2 -0.3 -0.4 -0.5
40 60 80 100 120 140 160
180 200 220
40 60 80 100 120 140 160
180 200 220
Angle (Degrees From True North)
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Measured Antenna Patterns (4 ft)
Antenna A
Antenna B
0.5 0.4 0.3 0.2 0.1 0.0 -0.1 -0.2 -0.3 -0.4 -0.5
40 60 80 100 120 140 160
180 200 220
40 60 80 100 120 140 160
180 200 220
Angle (Degrees From True North)
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ADCP Comparisons
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Radial Velocity Map
Brant Beach Site
Brigantine Site
Moored ADCP
25 km
A
25 cm/s
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Measured Site 1 Antenna Pattern
8 ft Ground Plane
4 ft Ground Plane
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ADCP and CODAR Radial Velocity Comparisons
Ideal Patterns
Measured Patterns
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Brant Beach Antenna Patterns
8 ft Ground Plane
4 ft Ground Plane
0.5 0.4 0.3 0.2 0.1 0.0 -0.1 -0.2 -0.3 -0.4 -0.5
A D C P
A D C P
40 60 80 100 120 140 160
180 200 220
40 60 80 100 120 140 160
180 200 220
Angle (Degrees From True North)
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ADCP and CODAR Radial Velocity Comparisons
RMS (cm/s)
R2 ()
Ground Plane
Remote Site
8 ft Brigantine 8.2
81
8 ft Brigantine 7.2
90
4 ft Brigantine 8.7
86
4 ft Brigantine 8.9
88
Ideal Patterns
Measured Patterns
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Brigantine Antenna Patterns
8 ft Ground Plane
4 ft Ground Plane
0.5 0.4 0.3 0.2 0.1 0.0 -0.1 -0.2 -0.3 -0.4 -0.5
A D C P
A D C P
40 60 80 100 120 140 160
180 200 220
40 60 80 100 120 140 160
180 200 220
Angle (Degrees From True North)
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Measuredvs.Ideal
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Radial Velocity Map
Location

• Range
• Bearing

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CODAR and ADCP Radial Velocity Comparisons (8 ft)
Ideal Patterns Measured Patterns
A D C P
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(No Transcript)
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Summary

• Hardware setup and local environment play a
  significant role in pattern distortions
• System accuracy improves with the measured
  patterns only when the measured patterns differ
  from the ideal.
• Measured patterns improve system accuracy by
  placing the velocity vectors in the correct
  angular bin.

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Acknowledgements

• Scott Glenn
• John Fracassi
• Sage Lichtenwalner
• Don Barrick
• Pete Lilliboe

• Belinda Lipa
• Liz Creed
• Mike Crowley
• Capt. Ron
• Capt. Joe