AN EASILY DEPLOYED AND RECOVERED GPS-TRACKED WATER LEVEL BUOY USM GPS Workshop - March 2004 NOAA SMALL BUSINESS INNOVATION RESEARCH (SBIR) PHASE II PROJECT Marshall Earle, Ph.D., Principal Investigator Mike Brown, Lead Electrical Engineer Jeffrey Gallagher, Electrical Engineer (Bill Hughes, Lead Mechanical Engineer) GPS-TRACKED BUOY KEY SPECIFICATIONS •Weight in air with battery packs 110 kg Diameter of hull 0.89 m Height with radio antenna 1.37 m Height 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 light Operating 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 antennas Microwave Data Systems narrow band CPFSK transceiver, operating at 410.0625 MHz (frequency band assigned to NOAA) Onset Computer Tattletale Model 8 microprocessor Texas Instruments MSP-430 microcontroller MuRata 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. ELECTRONIC AND DATA ANALYSIS DESIGN BUOY ELECTRONICS WATER LEVEL CALCULATION FLOWCHART SHORE STATION ELECTRONICS BASE STATION SETUP ON WAVELAND BEACH CHECKING THE BUOY ON THE BEACH VIA ITS INFRA-RED PORT REFERENCING TO BENCHMARK PANAMA CITY BEACH, FL, 1 Shore base station installed at benchmark. REFERENCING TO BENCHMARK PANAMA 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) NSI Base Station 3.50 NOAA Tide Station 3.00 2.50 2.00 1.50 1.00 0.50 0.00 0:00:00 3:12:00 14:24:00 17:36:00 14:00:00 20:48:00 17:12:00 20:24:00 23:36:00 0:48:00 7:36:00 4:00:00 0:24:00 7:12:00 3:36:00 6:48:00 6:24:00 18:00:00 21:12:00 10:48:00 10:24:00 13:36:00 10:00:00 16:48:00 13:12:00 Error detection routine later added to remove infrequent spikes. SMALL NOAA HYDROGRAPHIC VESSEL USED FOR CHESAPEAKE BAY, MD, DEPLOYMENT BUOY DEPLOYMENT CHESAPEAKE BAY, MD DEPLOYED BUOY CHESAPEAKE 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 cm RMS 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) SignificantWave Height Average Wave Period •Wave height accuracy +/- 0.2 m (could reach +/- 0.1 m) •Wave period accuracy +/- 1.0 s (could reach +/- 0.5 s) 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.
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