NAVO/PSI Buoy. Equipped with RTK GPS Rover Receiver, Buoy attitude and motion sensors, data acquisition system, and telemetry system. Reference Station Equipped with RTK GPS Reference Receiver, telemetry transmitter/receiver system, PC based data storage, Control software to interact with buoy system. 2-way data communications link. RTK for 2-cm accuracy requires path length of 10-km (6.2 miles) or less. RTK GPS Water-Level Measurement Buoy System © Planning Systems Incorporated Engineering Center, Aug 2002 Buoy based RTK GPS system receives RTK corrections, processes data. GPS RTK data stored aboard buoy. Buoy also processes and stores GPS antenna x,y,z motion. Processing determines water level after accounting for buoy motion in the seaway. Reference station, shore or off-shore structure based, provides RTK corrections to buoy GPS system via high power data link. When needed data link send commands to buoy or downloads data files (off-line). RTK data link requires at least 9600 bps is needed. Line of sight requires approximately 10’ buoy antenna height and 15’ reference station height.

RTK GPS Water-Level Measurement Buoy System © Planning Systems Incorporated Engineering Center, Jan 2001 RTK & data telemetry antenna GPS L1/L2 Receiver antenna Telemetry Radio & Solar Power Controller Buoy Attitude Sensors (magnetometer, accelerometer, vertical reference, pressure) RTK L1/L2 Receiver Pentium CPU, 20GB HDD, EtherNet, RS- 232 Ports, Digital Ports, PC-104 interface for A/D Electronics and BatteryRack 60 Watt solar panels 20° angle) 4 Sealed Pressure Regulated Secondary Batteries Buoy Dimensions 12-feet waterline to antenna top 5-feet draft from waterline 1200 lb total weight

RTK GPS Water-Level Measurement Buoy System © Planning Systems Incorporated Engineering Center, Aug 2002 RTK GPS System Description Reference Station and Buoy GPS – NovAtel OEM-4 L1/L2, 12 channel, RTK differential capable 6 – 18 VDC, 2.7 Watts -40°C to +85°C operating temperature 95% non-condensing humidity Reference Station GPS Antenna - NovAtel Model 503 Dual frequency antenna and choke ring with radome Buoy GPS Antenna - NovAtel Model 600 Dual frequency antenna Radio Modem -FreeWave® DGR-115R 900MHz, Spread Spectrum, VDC Base Station Telemetry Antenna -Cushcraft PC9013N Yagi Buoy Telemetry Antenna -Cushcraft S8964B Omni Antenna

RTK GPS Water-Level Measurement Buoy System © Planning Systems Incorporated Engineering Center, Aug 2002 Attitude Measurement System Accelerometers -Crossbow Technologies CXL02LF3 3-axis, ± 2 g, 1-V/g (calibrated sensitivity & offset) 8 – 30 VDC, with integrated 5 VDC regulator, 12-mA -40°C to +85°C operating temperature Magnetometers -Watson Industries, Inc., FGM axis, ± 70,000 nT, 20nT/mV 6 – 15 VDC, 30mA -50 °C to +80°C operating temperature Vertical Reference - Watson Industries, Inc. ADS-C232-1A Dual axis integrated sensor measuring tilt x/y Displacement & x/y angular rate ± 15 VDC, 60mA, -20 °C to +50°C operating temp. Pressure Sensor -SenSym Model SX30 0 – 30 psi +12 VDC, -40 °C to +85°C operating temp.

RTK GPS Water-Level Measurement Buoy System © Planning Systems Incorporated Engineering Center, Aug 2002 Data Acquisition System Single Board Computer -WinSystems ® EBC-TXPlus, 256MB RAM, 20GB HDD 166MHz Pentium w/ EIDE, Ethernet, Video, PC VDC, with ± 12 VDC for PC °C to +85°C operating temperature Analog-to-Digital Converter - WinSystems ® PCM-A/D-12 3-axis, ± 70,000 nT, 20nT/mV +5 VDC, 200mA w/installed DC/DC Converter -40 °C to +80°C operating temperature Watch Dog Timer - Parallax Basic Stamp II Programmable to cause full power reset Development System - WinSystems ® SDK2-EBX-104-D Software -ANSI C using MSDOS 6.22 Interrupt driven data acquisition sync’d to GPS

© Planning Systems Incorporated Engineering Center, Aug 2002 Buoy Power Budget Power Supply Required: 4 faces with 1 SX65 (65Watt) Solar Panels. The following tables show that the buoy power system should operate in the average conditions for the northern Gulf of Mexico in September. Previous experience with the buoy showed that the solar power system was able to recharge the secondary batteries and maintain the load without any interruptions. Buoy uses a Morningstar ProStar-30 Solar Controller to efficiently control battery conditioning during deployment. Power Demand (Ah/Day) RTK GPS Receiver 5.4 RTK Receiver/transmitter 4.8 HDD 0.2 PCU, PC-104 A/D43.6 Attitude Sensors 0.9 Est’ed Daily power requirement54.9 Ah/Day Power Supply (Ah/Day) Worse case simulation. 4 faces (SW, SE, NW, NE; using Siemans SX60 panels, 1 per face. September, Gulf of Mexico FaceAh/Day S16.45 E14.27 W N Total available55.96 Ah/day RTK GPS Water-Level Measurement Buoy System

© Planning Systems Incorporated Engineering Center, Aug 2002 Buoy Rover System Architecture +12VDC +5VDC +/-15VDC +/-12VDC Radio Modem WinSys CPU NovAtel OEMRT2 GPS Com1 Null Modem Com Com2 Straight Cable PC104 A/D 20GB HDD EIDE 3-axis Accelerometer 3-axis Magnetometer Vertical Reference House Keeping 4 faces SX-60 Solar Panels 4 Schottky Blocking Diodes 90SQ040 ProStar 30 Solar Controller PC104 DC/DC Converter DC/DC Converter Pressure Sensor (Depth) Watchdog Timer Power Relay

RTK GPS Water-Level Measurement Buoy System © Planning Systems Incorporated Engineering Center, Aug 2002 Shore-side GPS Reference Station Architecture Radio Modem Com 1 Straight Cable WinSys CPU Com2 Com1 20GB HDD EIDE RTK GPS Reference Station Com2 Null Modem 12VDC Converter 120VAC Mains