Upload
noel-thornton
View
217
Download
0
Tags:
Embed Size (px)
Citation preview
NAVO/PSI Buoy. Equipped with RTK GPS Rover Receiver, Buoy attitude and motion sensors, data acquisition system, and telemetry system.
Reference StationEquipped 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 of10-km (6.2 miles) or less.
RTK GPS Water-Level Measurement Buoy System
© Planning Systems IncorporatedEngineering 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 IncorporatedEngineering 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 (4 @ 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 IncorporatedEngineering 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, 9.50-014.0 VDC
Base Station Telemetry Antenna - Cushcraft PC9013N Yagi
Buoy Telemetry Antenna - Cushcraft S8964B Omni Antenna
RTK GPS Water-Level Measurement Buoy System
© Planning Systems IncorporatedEngineering 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-301
3-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 IncorporatedEngineering Center, Aug 2002
Data Acquisition System
Single Board Computer - WinSystems® EBC-TXPlus, 256MB RAM, 20GB HDD
166MHz Pentium w/ EIDE, Ethernet, Video, PC-104
+5 VDC, with ± 12 VDC for PC-104
-40°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 IncorporatedEngineering 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/D 43.6
Attitude Sensors 0.9
Est’ed Daily power requirement 54.9 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
Face Ah/Day
S 16.45
E 14.27
W 14.27
N 10.97
Total available 55.96 Ah/day
RTK GPS Water-Level Measurement Buoy System
RTK GPS Water-Level Measurement Buoy System
© Planning Systems IncorporatedEngineering Center, Aug 2002
Buoy Rover System Architecture
+12VDC
+5VDC
+/-15VDC+/-12VDC
RadioModem
WinSysCPU
NovAtelOEMRT2
GPS
Com1
Com1
Null Modem
Com
Com2
Straight Cable
PC104A/D
20GBHDD
EIDE
3-axisAccelerometer
3-axisMagnetometer
VerticalReference
HouseKeeping
4 facesSX-60
Solar Panels
4 SchottkyBlocking Diodes
90SQ040
ProStar 30Solar Controller
PC104 DC/DCConverter
DC/DCConverter
PressureSensor (Depth)
WatchdogTimer
PowerRelay
RTK GPS Water-Level Measurement Buoy System
© Planning Systems IncorporatedEngineering Center, Aug 2002
Shore-side GPS Reference Station Architecture
RadioModem
Com 1Straight Cable
WinSysCPU
Com2
Com1
20GBHDD
EIDE
RTK GPSReference
Station
Com
2
Nul
l M
odem
12VDCConverter
120VAC Mains