th insat satellite based data collection & tracking system for ocean data buoys s. n. satashia,...
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INSAT SATELLITE BASED DATA COLLECTION & TRACKING SYSTEM FOR
OCEAN DATA BUOYS
S. N. Satashia, Prem Kumar, M. Jeyamani &
Tata Sudhakar
Space Application Centre Ahmedabad & NIOT Chennai
BY
Tata Sudhakar
National Institute of Ocean Technology, Chennai
• The system uses Data Relay Transponder(DRT) of the Satellites
• The satellite receives transmission from data buoy in UHF band(402MHz) and retransmits to ground station in C band(4.5GHz).
• There are two satellites having DRT transponders INSAT 3A at location 93.5E and METSAT (KALPANA) satellite at location 74E.
INSAT BASED DATA COLLECTION SYSTEM
INSAT DRT coverage
FEATURES OF THE INSAT SATELLITES
INSAT 3A
C band Transponder :12
Ext C band Transponder :6
Ku band Transponder :6
DRT&SAS&R Transponders :1
Met Transmitter(VHRR&CCD) :1
METSAT(KALPANA)
DRT & SAS&R Transponder :1
Met Transmitter(VHRR) :1
PRESENT DCP
• India Meteorological Department
• Central Water Commission
• Snow& Avalanche Establishment
• NIOT
• State Agencies
• Transmit power 10W (Typ.)
• Transmit at 4.8Kbps in random mode in allotted
time window.
• Uses Directional antenna of gain 11dB (Typ.)
• Uses 3.8m Ground Receive station (Hub)
CHARACTERISTICS OF THE
TRANSMITTER (DCP)
Rx. Frequency Range : 402.75Mhz. 100KHz.Rx. G/T : - 19.0dB/ KReceive Polarization : Circular(RHCP for METSAT
&LHCP for INSAT 3A)Down link frequency : 4505 MHz (Nominal)Transmit Polarization : LinearEIRP (EOC) :18dBW
DRT TRANSPONDER CHARACTERISTICS
Satellite Link Design for Data Buoys
• The Transmit power from the data buoy is 10W.
• The transmit data rate is 300bps.
• Forward Error Correction Coding (convolution Coding) for the satellite channel is employed.
•Packet Error rate Probability(PEP)is kept as 0.01.
•Time Division Multiple Access(TDMA) transmission protocol employed with time synchronized to GPS received time.
Satellite Link calculation
UP LINK:
Up link frequency : 402.710MHz. Tx power : 10dBWAntenna gain (including cable loss) : -3dBiTx. EIRP : 7dBWMax. Slant range to satellite (at 5 deg. Ele) : 41130 KmUplink path loss : 177 dBSatellite G/T : -19dB/K
: EIRP - path loss + G/T+K Uplink C/No : 39.6dBHz DOWN LINK: Down link freq. : 4505MhzDown link path loss : 197.0dBSatellite EIRP : -1dBWDown link path loss : 197.0dbG/T of earth station (3m) : 17dB/KDown link C/No : EIRP - Path loss+ G/T+k
: 47.6dBHzTotal C/No : 39.5dBHzRequired C/No : 34dBHzLink Margin : 5.5dB
UHF TRANSMITTER
(10W)
DATA COLLECTION FROM DATA BUOY THROUGH INSAT
UHF(402MHz)
Data Acquisition
(CPU)
GPS
Data from Sensors
LNA RFD/C
BURSTDEMOD(BPSK)
70MHz IF 300b/s
C-BAND(4.5GHz)
To data processing system of NIOT
3.8m
INSAT
Message Generator
Frequency Synthesizer
(UHF)
Power Amplifier
(10W)
BPSKModulator
Data from CPU
Block Schematics of INSAT UHF Transmitter
4.8Kbaud
402MHz
300bbps (1/2 rate)
F(8)
MID(16)
IINFORMATION
(320)
CRC(16)
F
(8)
DATA FORMAT
BURST FORMAT OF TRANSMISSION
CR BTR UW
1.68Sec sec
256 64 64 UP TO 752 SYMBOLS
SCRAMBLED AND ½ RATE CODED
CR Carrier Recovery
BTR Bit Timing Recovery
UW Unique Word
Specification of Receive station(HUB)
Receive frequency :4505MHzG/T of Receive station (3.8m) : 22dB/KIF Input to BPSK demodulator :70MHz (nominal)Output data rate & level : 300b/s, RS 232Output data frame format (Demod) : HDLCInput to data processing unit :4800baud
TEST RESULT OF SATELLITE LOOP
TX power
C/No
(dBHz)
Packets % PEPRx / Tx
1W 32.3 80/100 0.2
1.25W 33.3 90/100 0.1
1.5W 34.3 96/100, 95/100, 0.0496/100
2.5W 36.3 98/100 0.02
9W 41.8 98/100 0.02
1. THE EXPERIMENT RESULTS SHOW THAT INSAT SUPPORTS DATA BUOY COMMUNICATION WITH ADEQUATE MARGIN
2. OCCASIONAL LOSS OF DATA DUE TO INTERFERENCE FROM OTHER GROUND SYSTEM IS TAKEN CARE OF BY DIFFERENTIAL CODING and REPEAT TRANSMISSION.
INSAT Transmitter and Antenna for data buoys
INDIA
Arabian SeaBay of Bengal
SW6
DS1
DS3
Chennai
Machillipatnam
Mangalore
Tuticorin
Goa
Mumbai
NIOT
Pipvav
Off Paradip
DATA BUOYS WITH INSAT COMMUNICATION
Data Buoy with Insat communication
Buoy with Insat Position reporting system
NIOT Hub and INSAT DRT capacity
A hub station has been commissioned at NIOT in association with SAC Ahmedabad to establish the INSAT link for buoy communication.
Successfully carried out the preliminary tests
INSAT (METSAT & INSAT 3A) can handle communication up to 1200 platform/ hour/carrier.
TRACKING SYSTEM
Information Rate 300 BPS
Format HDLC
Message Length 40 Characters (Max)
Error Protection 16 bit CRC
Error correction rate
600 BPS
Modulation BPSK, bust
External Data RS-232 Interface (GPS,NMEA - 0183D)
Transmission 3 Packets/message randomized – Aloha mode.
1 Packet / Message - TDMA mode
Transmission time 4 sec (Max) / Message
Frequency band 2677.56 to 2678.56 MHz
Freq. Uncertainty ± 2.7 KHz Max.
Antenna Coverage ± 45°
Tx EiRp 9 dBW (min.)
Power Supply Li - Ion -12 V DC, 600 mAh, Rechargeable Battery
Temperature 0 to + 50° C
MSS Terminal SpecificationMSS Terminal Specification
Buoy fitted with MSS transmitter is ready for deployment.
MSS - TRANSMITTERMSS - TRANSMITTER
Message Generator
Frequency Synthesizer
Power Amplifier
BPSKModulator
GPS Receiver
Emergency Switch
Battery
Block Schematics of Alert Transmitter
Thank you