Marshall Earle, Ph.D., Principal InvestigatorMike Brown, Lead Electrical EngineerJeffrey Gallagher, Electrical Engineer

(Bill Hughes, Lead Mechanical Engineer)

AN EASILY DEPLOYED AND RECOVEREDGPS-TRACKED WATER LEVEL BUOY

USM GPS Workshop - March 2004

NOAA SMALL BUSINESS INNOVATION RESEARCH(SBIR) PHASE II PROJECT

GPS-TRACKED BUOY

KEY SPECIFICATIONS

•Weight in air with battery packs 110 kgDiameter of hull 0.89 mHeight with radio antenna 1.37 mHeight w/o antenna 0.97 m•Nearly spherical hull with polycarbonate and anodized 6061T0 aluminum hemispheres, non-pinching gasket seal with stainless steel bolts, navigation lightOperating life 1 month•Operating Temperature Range -30oC to +60oC•Outputs: water level, significant wave height, average wave period, Data Quality Control (DQC) parameters

•See the preliminary specification sheet for additional information.

KEY COMPONENTS

•Topcon Legacy E GPS Topcon LegAnt GPS / GLONASS antennasMicrowave Data Systems narrow band CPFSK transceiver, operating at 410.0625 MHz (frequency band assigned to NOAA) Onset Computer Tattletale Model 8 microprocessorTexas Instruments MSP-430 microcontrollerMuRata ENV-05DB-52 angular rate sensors (3)Crossbow Technology CXL02TG3 tri-axial accelerometer•Carmanah Technologies 701 solar powered navigation light

BUOY IN SMALL PICKUP TRUCK BEFORE FIELD TEST

DOME REMOVAL / REPLACING

UPPER PLATE COMPONENTS

LOWER PLATE AND ELECTRONICS UNIT

ELECTRONICS UNIT INTERNAL VIEW

ELECTRONICS UNIT LABELLED COMPONENTS

BATTERY PACK REMOVAL / REPLACING

BUOY EXPLODED VIEW

BUOY CROSS SECTIONAL VIEW

PLANNED BUOY MODIFICATIONS

EXAMPLE BUOY MOORING

EXAMPLE SCREEN SHOT OF BUOY USER INTERFACE

Data steps are due to changing the buoy's water level in a test tank.

BUOY ELECTRONICS

SHORE STATION ELECTRONICS

WATER LEVEL CALCULATIONFLOWCHART

ELECTRONIC AND DATA ANALYSIS DESIGN

BASE STATION SETUP ON WAVELAND BEACH

CHECKING THE BUOY ON THE BEACH VIA ITS INFRA-RED PORT

REFERENCING TO BENCHMARKPANAMA CITY BEACH, FL, 1

Shore base station installed at benchmark.

REFERENCING TO BENCHMARKPANAMA CITY BEACH, FL, 2

Shore base station antenna installed in final position.

PANAMA CITY BEACH, FL, DATA COMPARISON

6 minute Tidal Measurements w/r to MLLW (ft)

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

18:0

0:00

0:48

:00

7:36

:00

14:2

4:00

21:1

2:00

4:00

:00

10:4

8:00

17:3

6:00

0:24

:00

7:12

:00

14:0

0:0

0

20:4

8:00

3:36

:00

10:2

4:00

17:1

2:00

0:00

:00

6:48

:00

13:3

6:00

20:2

4:00

3:1

2:00

10:0

0:00

16:4

8:00

23:3

6:00

6:24

:00

13:1

2:00

NSI Base Station

NOAA Tide Station

Error detection routine later added to remove infrequent spikes.

SMALL NOAA HYDROGRAPHIC VESSELUSED FOR CHESAPEAKE BAY, MD, DEPLOYMENT

BUOY DEPLOYMENTCHESAPEAKE BAY, MD

DEPLOYED BUOYCHESAPEAKE BAY, MD

CHESAPEAKE BAY, MD, DATA COMPARISON

Infra-red port lockup caused some data loss (corrected in operational design).

WATER LEVEL DATA COMPARISONS

•Panama City Beach, FL

RMS difference (including mean difference) 3.76 cmRMS difference (mean removed) 1.96 cm

•Chesapeake Bay, MD

Mean difference determined and removed at start of data collection.RMS difference 1.45 cm

WAVES (NOT MAIN RESEARCH GOAL)

•Wave height accuracy +/- 0.2 m (could reach +/- 0.1 m)•Wave period accuracy +/- 1.0 s (could reach +/- 0.5 s)

SignificantWave Height Average Wave Period

SUMMARY

A GPS-tracked water level buoy that can be easily deployed and recovered from small or large vessels has been successfully designed, built, and field tested.

The buoy is ready for transition to operational use to support hydrographic surveys and other applications.