influence of antenna pattern distortions on surface current data collected by a codar hf-radar...

Influence of Antenna Pattern Distortions Influence of Antenna Pattern Distortions on Surface Current Data collected by a on Surface Current Data collected by a

CODAR HF-Radar SystemCODAR HF-Radar System

Josh T. KohutJosh T. KohutScott M. GlennScott M. Glenn

Donald E. BarrickDonald E. Barrick

Radial Velocity MapRadial Velocity Map

A

Brigantine Site

Moored ADCP

25 km

25 cm/s

Brant Beach Site


A

Brigantine Site

Moored ADCP

25 km

25 cm/s

Brant Beach Site

• Range• Bearing

Location

AntennaAntennaPatternsPatterns

Role of Antenna Patterns in SignalRole of Antenna Patterns in SignalDirection DeterminationDirection Determination

Role of Antenna Patterns in SignalRole of Antenna Patterns in SignalDirection DeterminationDirection Determination

Loop 1Loop 2Monopole

0 . 2 4 0 . 4 8 0 . 7 2 0 . 9 6 1 . 2

6 0

2 4 0

3 0

2 1 0

0

1 8 0

3 3 0

1 5 0

3 0 0

1 2 0

2 7 0 9 0

N o r t h - S i t e A n t e n n a P a t t e r n s w i t h 8 - f o o t R a d i a l G r o u n d E l e m e n t s :S o l i d l i n e s - - m e a s u r e d p a t t e r n s ; d a s h e d l i n e s - - i d e a l p a t t e r n s N o r t h - S i t e A n t e n n a P a t t e r n s w i t h 4 - f o o t R a d i a l G r o u n d E l e m e n t s :S o l i d l i n e s - - m e a s u r e d p a t t e r n s ; d a s h e d l i n e s - - i d e a l p a t t e r n s

0 . 2 6 3 8 0 . 5 2 7 6 0 . 7 9 1 3 9

6 0

2 4 0

3 0

2 1 0

0

1 8 0

3 3 0

1 5 0

3 0 0

1 2 0

2 7 0 9 0

Measured vs. Ideal Antenna PatternsMeasured vs. Ideal Antenna Patterns

Calibration Runs

RunNumber

GroundPlane

Environment Antenna Date

1 8ft Brigantine Brigantine 10/99


3 8ft Brant Beach Brant Beach 10/99



6 4ft Brant Beach Brigantine 09/00

Measured Brant Beach Antenna PatternsMeasured Brant Beach Antenna Patterns

8 ft Ground Plane 4 ft Ground Plane

Loop 1Loop 2

Measured Brant Beach Antenna PatternsMeasured Brant Beach Antenna Patterns


Loop 1Loop 2

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)

0.5

0.4

0.3

0.2

0.1

0.0

-0.1

-0.2

-0.3

-0.4

-0.5

Calibration Runs

RunNumber

GroundPlane








Measured Antenna Patterns (4 ft)Measured Antenna Patterns (4 ft)

Brant Beach, NJ

Loop 1Loop 2

Brigantine, NJ

40 60 80 100 120 140 160 180 200 220 40 60 80 100 120 140 160 180 200 220


0.5

0.4

0.3

0.2

0.1

0.0

-0.1

-0.2

-0.3

-0.4

-0.5

Calibration Runs

RunNumber

GroundPlane








Measured Antenna B PatternsMeasured Antenna B Patterns

Brant Beach, NJ

Loop 1Loop 2

Brigantine, NJ

40 60 80 100 120 140 160 180 200 220 40 60 80 100 120 140 160 180 200 220


0.5

0.4

0.3

0.2

0.1

0.0

-0.1

-0.2

-0.3

-0.4

-0.5

Measured Antenna Patterns (4 ft)Measured Antenna Patterns (4 ft)

Antenna A

Loop 1Loop 2

Antenna B

40 60 80 100 120 140 160 180 200 220 40 60 80 100 120 140 160 180 200 220


0.5

0.4

0.3

0.2

0.1

0.0

-0.1

-0.2

-0.3

-0.4

-0.5

ADCP ADCP ComparisonsComparisons


A

Brigantine Site

Moored ADCP

25 km

25 cm/s

Brant Beach Site

Measured Site 1 Antenna PatternMeasured Site 1 Antenna Pattern


Loop 1Loop 2

GroundPlane

Remote SiteRMS(cm/s)

R2

(%)

8 ft Brant Beach 12.2 60




Ideal Patterns Measured Patterns

ADCP and CODAR Radial Velocity ComparisonsADCP and CODAR Radial Velocity Comparisons

Brant Beach Antenna PatternsBrant Beach Antenna Patterns


Loop 1Loop 2

40 60 80 100 120 140 160 180 200 220 40 60 80 100 120 140 160 180 200 220


0.5

0.4

0.3

0.2

0.1

0.0

-0.1

-0.2

-0.3

-0.4

-0.5

ADCP

ADCP

GroundPlane

Remote SiteRMS(cm/s)

R2

(%)

Ideal Patterns Measured Patterns

ADCP and CODAR Radial Velocity ComparisonsADCP and CODAR Radial Velocity Comparisons

8 ft Brigantine 8.2 81




Brigantine Antenna PatternsBrigantine Antenna Patterns


Loop 1Loop 2

40 60 80 100 120 140 160 180 200 220 40 60 80 100 120 140 160 180 200 220


0.5

0.4

0.3

0.2

0.1

0.0

-0.1

-0.2

-0.3

-0.4

-0.5

ADCP

ADCP

MeasuredMeasuredvs.vs.

IdealIdeal


A

Brigantine Site

Moored ADCP

25 km

25 cm/s

Brant Beach Site

• Range• Bearing

Location

CODAR and ADCP Radial Velocity Comparisons (8 ft)

Ideal PatternsMeasured Patterns

ADCP

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.

SummarySummary

Scott Glenn John Fracassi Sage Lichtenwalner Don Barrick Pete Lilliboe

AcknowledgementsAcknowledgements

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

influence of antenna pattern distortions on surface current data collected by a codar hf-radar...

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